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Suggestions on Micrometer, Calipers??
What are some features to look for in a micrometer or caliper? Are the ones
at Harbor Freight worth considering? I have a $20 micrometer from Sears, but I think it may not be too accurate. I am looking to mainly measure items that are .1mm - .3mm in thickness (weekly use), but sometimes stuff that is larger (monthly or yearly). I wouldn't need to measure anything larger than 3"/75ish mm. I saw a 3 piece kit at Harbor Freight that has a 0-25mm micrometer, 25 - 50mm micrometer and 50 - 75 mm micrometer. Has anyone seen that one? What makes a Starett/Mitutuyo/etc. brand so much more better (expensive too)? Thank you. |
Suggestions on Micrometer, Calipers??
JWho wrote:
What are some features to look for in a micrometer or caliper? Oh, that doesn't matter that much. I would take any mike someone has written "Mitutoyo" on it. As long as the writing wasn't done with an edding. :-) What makes a Starett/Mitutuyo/etc. brand so much more better (expensive too)? You have them a live long. Accuracy, repeatability and quality. That costs and pays back. Nick -- Motor Modelle // Engine Models http://www.motor-manufaktur.de DIY-DRO - YADRO - Eigenbau-Digitalanzeige |
Suggestions on Micrometer, Calipers??
I have over the last 15 years or so bought several lots of machinist tools, so
I've gotten quite a few different things in my hands to look at. My main set of micrometers is a nice Lufkin 0-6" set in a wooden box, very chi-chi. However, when it was time for me to tool up to go do 2 quarters of machine shop classes at night school and leave my tools there in my locker, I took only tools that I felt I could live without because the risk of theft was very high. Among those tools was a 0-1" Craftsman Professional micrometer. I used that a lot in the lathe class, and grew to really like it. It seems to me (as big a snob as anyone) that it is made very well indeed, and appears to work perfectly. Later I sought out and found a 1-2" matching Craftsman Professional mic, and I like it too. Still later someone told me that these are made for Craftsman by Starrett, which would explain everything. The kicker is that with Craftsman stuff having gone so far downhill since the '70s, the older Craftsman Professional machinist tools go *cheap*. I paid the princely sum of $4 for my 1-2" mic on ebay. So my advice is, if you're starting out, you could do much worse than go find some Craftsman Professional stuff on ebay. Also, there are two kinds of calipers, which causes horrible confusion. One kind often has a little readout and is basically like a 6" rule, maybe a dial or digital caliper. The other kind has 2 legs, comes in inside, outside and hermaphrodite, and I find it very confusing that they are all called "calipers". Anyway, I have a whole bunch of the latter and if you're interested email me offline. I've been decluttering lately, which means selling stuff, and these are quite inexpensive. See: http://seattle.craigslist.org/tls/108149920.html GWE Kirkland, Washington JWho wrote: What are some features to look for in a micrometer or caliper? Are the ones at Harbor Freight worth considering? I have a $20 micrometer from Sears, but I think it may not be too accurate. I am looking to mainly measure items that are .1mm - .3mm in thickness (weekly use), but sometimes stuff that is larger (monthly or yearly). I wouldn't need to measure anything larger than 3"/75ish mm. I saw a 3 piece kit at Harbor Freight that has a 0-25mm micrometer, 25 - 50mm micrometer and 50 - 75 mm micrometer. Has anyone seen that one? What makes a Starett/Mitutuyo/etc. brand so much more better (expensive too)? |
Suggestions on Micrometer, Calipers??
On Fri, 04 Nov 2005 07:30:15 -0800, Grant Erwin
wrote: Anyway, I have a whole bunch of the latter and if you're interested email me offline. I've been decluttering lately, which means selling stuff, and these are quite inexpensive. See: http://seattle.craigslist.org/tls/108149920.html GWE Kirkland, Washington Coming this way anytime soon? Gunner "Pax Americana is a philosophy. Hardly an empire. Making sure other people play nice and dont kill each other (and us) off in job lots is hardly empire building, particularly when you give them self determination under "play nice" rules. Think of it as having your older brother knock the **** out of you for torturing the cat." Gunner |
Suggestions on Micrometer, Calipers??
"JWho" wrote in message news:I%Iaf.516772$_o.377448@attbi_s71... What are some features to look for in a micrometer or caliper? Are the ones at Harbor Freight worth considering? I have a $20 micrometer from Sears, but I think it may not be too accurate. I am looking to mainly measure items that are .1mm - .3mm in thickness (weekly use), but sometimes stuff that is larger (monthly or yearly). I wouldn't need to measure anything larger than 3"/75ish mm. I saw a 3 piece kit at Harbor Freight that has a 0-25mm micrometer, 25 - 50mm micrometer and 50 - 75 mm micrometer. Has anyone seen that one? What makes a Starett/Mitutuyo/etc. brand so much more better (expensive too)? Thank you. The one thing you must understand is that calipers, vernier, dial, or digital, in NO way will be anywhere near as accurate as a micrometer----nor are they intended to be. Micrometers, even those that are not calibrated in tenths, are far more precise than are calipers------by design. One of the things you must do is make your decision based on your needs. If you are concerned about a thou, then don't rely on calipers. If you don't care if you are off a few tenths, a cheap micrometer will suffice. The more expensive measuring tools are generally more reliable, although that isn't a given. I bought a new Mitutoyo dial caliper that varied by ..002", inside to outside measurements. That was excessive, and they were returned. I asked for a replacement, not a refund, for I have great faith in the Mitutoyo name, having used many of their measuring tools and finding them to be superior in some instances to Starrett, which I own almost exclusively. Bottom line: buy both, mics and calipers, if you can afford them. Each has a place, but it's important for you to understand which is proper for the application at hand. Harold |
Suggestions on Micrometer, Calipers??
On Fri, 4 Nov 2005 10:08:43 -0800, "Harold and Susan Vordos"
wrote: "JWho" wrote in message news:I%Iaf.516772$_o.377448@attbi_s71... What are some features to look for in a micrometer or caliper? Are the ones at Harbor Freight worth considering? I have a $20 micrometer from Sears, but I think it may not be too accurate. I am looking to mainly measure items that are .1mm - .3mm in thickness (weekly use), but sometimes stuff that is larger (monthly or yearly). I wouldn't need to measure anything larger than 3"/75ish mm. I saw a 3 piece kit at Harbor Freight that has a 0-25mm micrometer, 25 - 50mm micrometer and 50 - 75 mm micrometer. Has anyone seen that one? What makes a Starett/Mitutuyo/etc. brand so much more better (expensive too)? Thank you. The one thing you must understand is that calipers, vernier, dial, or digital, in NO way will be anywhere near as accurate as a micrometer----nor are they intended to be. Micrometers, even those that are not calibrated in tenths, are far more precise than are calipers------by design. One of the things you must do is make your decision based on your needs. If you are concerned about a thou, then don't rely on calipers. If you don't care if you are off a few tenths, a cheap micrometer will suffice. The more expensive measuring tools are generally more reliable, although that isn't a given. I bought a new Mitutoyo dial caliper that varied by .002", inside to outside measurements. That was excessive, and they were returned. I asked for a replacement, not a refund, for I have great faith in the Mitutoyo name, having used many of their measuring tools and finding them to be superior in some instances to Starrett, which I own almost exclusively. Bottom line: buy both, mics and calipers, if you can afford them. Each has a place, but it's important for you to understand which is proper for the application at hand. Harold I work in machine shops as a machine tool repair tech. Given that most shops now days have few machinists..but lots of operators at lower pay scales..Chinese metrology equipment is very very common. Every calibrator Ive talked to says that 99.99% of Chinese mics etc etc will pass calibration every time, for at least 5 yrs of daily work, before they start getting worn out. Now if you are doing home stuff...that 5 yrs will translate into "grandchildrens bequest". If you are a pro..and need them to last for 30 yrs..by the big names. YMMV Gunner "Pax Americana is a philosophy. Hardly an empire. Making sure other people play nice and dont kill each other (and us) off in job lots is hardly empire building, particularly when you give them self determination under "play nice" rules. Think of it as having your older brother knock the **** out of you for torturing the cat." Gunner |
Suggestions on Micrometer, Calipers??
I work in machine shops as a machine tool repair tech. Given that
most shops now days have few machinists..but lots of operators at lower pay scales..Chinese metrology equipment is very very common. Every calibrator Ive talked to says that 99.99% of Chinese mics etc etc will pass calibration every time, for at least 5 yrs of daily I have a set of chineese mics from enco and they work fine. When I first got them, I would measure something with a starret or B&S and the enco and they compared well. I enve tried a couple Jo blocks and they seemed right on. They work well and the price is right. I also use the cheap enco calipers for everyday work. I have better ones, but I don't cry if I drop the cheap ones. chuck |
Suggestions on Micrometer, Calipers??
I bought a new Mitutoyo dial caliper that varied by
.002", inside to outside measurements. That was excessive, and they were returned. I asked for a replacement, not a refund, for I have great faith in the Mitutoyo name, having used many of their measuring tools and finding them to be superior in some instances to Starrett, which I own almost exclusively. I don't care for starrett mikes. Most of them have slanted lines which I find hard to read. My favorites are Brown and Sharp, followed closely by the more affordable Mitutoyo. |
Suggestions on Micrometer, Calipers??
Chuck Sherwood wrote:
I work in machine shops as a machine tool repair tech. Given that most shops now days have few machinists..but lots of operators at lower pay scales..Chinese metrology equipment is very very common. Every calibrator Ive talked to says that 99.99% of Chinese mics etc etc will pass calibration every time, for at least 5 yrs of daily I have a set of chineese mics from enco and they work fine. When I first got them, I would measure something with a starret or B&S and the enco and they compared well. I enve tried a couple Jo blocks and they seemed right on. They work well and the price is right. I also use the cheap enco calipers for everyday work. I have better ones, but I don't cry if I drop the cheap ones. I've had the same experience. The Enco mics get everyday use and I don't worry about them walking off. |
Suggestions on Micrometer, Calipers??
My favorites are Brown and Sharp, followed closely by the more affordable
Mitutoyo. I have heard that old Mitutoyo mics were great. Newer ones are not so great. That about about 7-8 years ago. Disclaimer: I don't own any Mitutoyo mics, but I do have some electronic calipers and I like them. |
Suggestions on Micrometer, Calipers??
We used to beat on this topic a lot back in the '90s. I have 3 6" calipers, all
in like-new condition. One is Browne & Sharp, one is Starrett (those two are dial calipers) and the 3rd is Mitutoyo digital. The one I use the most? The Browne & Sharp. Great tool. Actually, they're all good. If I had to let go of one, though, it would be the Starrett. GWE |
Suggestions on Micrometer, Calipers??
"Dave Lyon" wrote in message news:o_Paf.541319$xm3.343462@attbi_s21... I bought a new Mitutoyo dial caliper that varied by .002", inside to outside measurements. That was excessive, and they were returned. I asked for a replacement, not a refund, for I have great faith in the Mitutoyo name, having used many of their measuring tools and finding them to be superior in some instances to Starrett, which I own almost exclusively. I don't care for starrett mikes. Most of them have slanted lines which I find hard to read. I'm not sure what Starrett mic's you've seen, but I have eight of them, not one has slanted lines. I don't like them slanted, either. I'm well pleased with the Starrett line, and I have several of their tools, including gage blocks and height gage. That, of course, excludes the Last Word indicator, which I also own. Those suckers should be taken to court for selling such a low life piece of garbage. It's an insult to their quality. I own several of their long travel indicators and like them just fine. Harold |
Suggestions on Micrometer, Calipers??
On Fri, 04 Nov 2005 15:04:29 -0600, Rex B
wrote: Chuck Sherwood wrote: I work in machine shops as a machine tool repair tech. Given that most shops now days have few machinists..but lots of operators at lower pay scales..Chinese metrology equipment is very very common. Every calibrator Ive talked to says that 99.99% of Chinese mics etc etc will pass calibration every time, for at least 5 yrs of daily I have a set of chineese mics from enco and they work fine. When I first got them, I would measure something with a starret or B&S and the enco and they compared well. I enve tried a couple Jo blocks and they seemed right on. They work well and the price is right. I also use the cheap enco calipers for everyday work. I have better ones, but I don't cry if I drop the cheap ones. I've had the same experience. The Enco mics get everyday use and I don't worry about them walking off. I guess I should mention...most of my mics are NSK. Except the Harbor Frieght mechanical digital that works just hunky dorey. Gunner "Pax Americana is a philosophy. Hardly an empire. Making sure other people play nice and dont kill each other (and us) off in job lots is hardly empire building, particularly when you give them self determination under "play nice" rules. Think of it as having your older brother knock the **** out of you for torturing the cat." Gunner |
Suggestions on Micrometer, Calipers??
"JWho" wrote in
news:I%Iaf.516772$_o.377448@attbi_s71: What are some features to look for in a micrometer or caliper? You've gotten some good advice but I'll throw in my .02. Features to look for in a micrometer to me would be: Carbide faces - They wear longer and stay flatter over time. Downside is that carbide chips easily, so if you aren't going to be careful and organized don't bother. "Tenths" vernier - Allows you to measure to .0001" Spindle lock - Allows you to reach into a machine, measure, engage the lock, then remove the micrometer so you can read it. The lever types are easiest to use, they also break quicker than the knurled ring around a collar type. Adjustment for calibration - There are several schemes for this, the easiest to use are the type where the barrel is rotated by a small spanner wrench. The worst are the types where you have to remove the spindle, tweek it, then put it back together to see if you've done any good. Slip mechanism - This would be either a friction thimble or a ratchet on the end of the thimble. I prefer a friction thimble for measuring while holding the mic in my hand. I prefer the ratchet thimble for use in a micrometer stand. A micrometer stand will allow you to measure more repeatably and more accurately. Thimble diameter - Often an overlooked feature. I like my Starett because it's light and skinny (plus it was the first one I bought). OTOH, I don't like it for measuring "tenths". As I get older it's harder to read, plus it's prone to parallax error. A fat thimble like the one on my Helios gives me more consistant readings as the lines are spaced further apart and easier on my failing eyesight. If you aren't old now, just wait. Calipers are a different matter. First you need to decide which type you want; verniers, dial, or digital. In general: Verniers - they are the most accurate and repeatable of the bunch. They also will last damn near forever if used carefully and taken care of. They can be hard to read, and quick reading is not a feature built into these. Starrett 123 verniers are the best bar none. They are also very expensive. Mitutoyo makes a decent pair of six inch ones that can be bought new today. They are lighter and more frail than the Starrett, plus they aren't flush reading so parallax error can be a problem. Dial Calipers - The features I look for a Four way measurement. They can measure OD using the main jaws. ID's using the top jaws. Depth using the rod that comes out of the end. And steps using the outside edge of the fixed jaw and the outside edge of the moveable jaw. ..100" per revolution dial. Some calipers move .200" per revolution of the dial, these are harder to read. Covered gear rack - dial calipers have a gear rack that drives the clockworks when the moveable jaw slides. If chip get in there, the caliper at the very least can jump teeth resulting in an off center zero. At worst the gears become damaged and the caliper will no longer be accurate through out the range. Quality - They can range from nearly as good as a vernier to nearly worthless. I've used them all over the years. The Brown and Sharpes are the best. They are also the same as the Etalon and the Tesa dial calipers. The Etalon ones are usually more expensive because they have a pretty horse stamped on them;) If you go with the B&S calipers make sure they are the ones that say Swiss made. Mitutoyo is a decent second choice. They are a little light and not as smooth but overall they are OK. The Starretts aren't worth the money IMO. They are too soft and I don't like the feel of them. You could buy a Peacock brand (cheap Japanese) and get the same quality for a lot less. I don't like the Chinese ones at all. Dial calipers need to have precision gears, and quality assembly. They Stainless Steel should be quality and well hardened. Those qualities don't exist in Chinese dial calipers. Digital Calipers - You can pretty much buy a Mitutoto, Starrett, Brown and Sharpe, Etalon, or Tesa and end up with a damn nice tool. That being said, if your budget is tight the Chinese digital calipers aren't bad at all for the money. Buy them on Ebay and you'll save some money. The big brands are more coolant proof, have harder jaws, and better battery life. But if you can be careful with the Chinese ones, they are about as accurate. Just remove the battery between uses. They suck juice in a big way just sitting there turned off. Some don't turn off automatically either, but the difference in battery life is small. Only buy NEW calipers on Ebay. Micrometers are another matter, but calipers are easily damaged. Are the ones at Harbor Freight worth considering? No for the micrometers, and maybe for digital calipers. You can buy a perfectly good high quality used micrometer on Ebay for about what you'd pay for a Chinese one new. Starretts usually command a slightly higher price due to the name. But 0-1" Starretts are so common though the price is usually 1/3 - 1/4 of new. Mitutoyo's are decent and often go for cheap. But if you are savvy and patient you can snag a really nice micrometer for next to nothing. What you want to keep an eye out for are older Helios micrometers, newer Tesa, and Brown & Sharpes. Alos look for older MG brand, I bought one of these NOS, never used. It's a Lufkin rebranded. MG later became General brand. Don't touch those. The one you want will have carbide, tenths, and a unique friction thimble that is at the top of the thimble, plus a knurled ring lock. These are stamped "Made in USA". They were sold mainly in hobby stores, but they are Lufkin. I paid $3.00 for mine plus shipping. But be careful, some are cheap hobby type and are nearly worthless. If it doesn't have the above features don't bid. Also look for Mitutoyo "106" micrometers. They have a non rotating anvil and the model# starts with "106-" Hell here is a 1-2" http://cgi.ebay.com/MITUTOYO-MICROMETERS-1-2-INCH-75- OFF_W0QQitemZ7554844037QQcategoryZ92085QQssPageNam eZWD1VQQrdZ1QQcmdZViewI tem or http://tinyurl.com/7uwbp People don't know what these are and they sell cheap! Also look for JT Slocomb, Lufkin, and Etalon. Etalons usually sell for big bucks. I have a $20 micrometer from Sears, but I think it may not be too accurate. Older Craftsmen micrometers can be made by Starrett, Mitutoyo, or Helios. All very good. The new ones aren't worth a damn. I am looking to mainly measure items that are .1mm - .3mm in thickness (weekly use), but sometimes stuff that is larger (monthly or yearly). I wouldn't need to measure anything larger than 3"/75ish mm. I saw a 3 piece kit at Harbor Freight that has a 0-25mm micrometer, 25 - 50mm micrometer and 50 - 75 mm micrometer. Has anyone seen that one? They are probably like these http://tinyurl.com/9u5q3 Instead of Chinese look for the ones made in Poland. They are really quite nice - http://tinyurl.com/dl8vx They are usually called VIS or VIN brand. Sometimes they just say Poland. I would try to get used brand name first. At least for the 0-1". You will use it the most. Here is a guy with a bunch of new Mitutoyo digit mics listed http://search.ebay.com/_W0QQsassZadsotlarQQhtZ-1 Looks like they can be had for ten bucks plus shipping. Why buy Chinese? What makes a Starett/Mitutuyo/etc. brand so much more better (expensive too)? They are more accurate. They are made with better materials, have better fit, finish and feel. Often the frames and spindle are harder. Plus they stand behind what they sell. You can send tham a broken tool and they will fix it, or you can order parts from them. The tools are also traceable to NIST. -- Dan |
Suggestions on Micrometer, Calipers??
"D Murphy" wrote in message ... good stuff snipped-------- They are more accurate. They are made with better materials, have better fit, finish and feel. Often the frames and spindle are harder. Plus they stand behind what they sell. You can send tham a broken tool and they will fix it, or you can order parts from them. The tools are also traceable to NIST. Dan Well done, Dan. Harold |
Suggestions on Micrometer, Calipers??
"D Murphy" wrote in message
... "JWho" wrote in news:I%Iaf.516772$_o.377448@attbi_s71: What are some features to look for in a micrometer or caliper? Digital Calipers - snip if your budget is tight the Chinese digital calipers aren't bad at all for the money. Buy them on Ebay and you'll save some money. Are the ones at Harbor Freight worth considering? No for the micrometers, and maybe for digital calipers. Dan Excellent post Dan. I would just add a bit of clarifying info to the last part about Harbor Freight, as you addressed the issue of micrometers, but forgot to elaborate on the calipers. The electronic digital calipers sold at harbor Freight are essentially the same as all the Chinese import digital calipers sold on Ebay. So if you want one (or several in different sizes), you can probably get them cheaper and more conveniently at your local HF store (if you have one nearby). I have a 6" Mitutoyo digital caliper that is very accurate *AND* very precise (see below for why these terms are different). I also have a couple of the HF digital calipers in different sizes for the times I need smaller or larger (I bought a new 12" HF digital caliper for less than $40 in the store, whereas even a used 12" Mitutoyo of unknown condition will sell on Ebay for well over $200). I also will turn to the HF calipers for situations where I don't want to risk damage to my Mitutoyo caliper. I find the HF calipers are accurate enough for most hobby/small shop purposes. What annoys me the most about them is their apparent lack of precision: if I close the jaws and zero the display, then open and close the jaws, sometimes the "zero" position will read 0.01mm or -0.01mm. I'm not sure if it has to do with an imperfection in the mechanical construction which prevents the jaws from closing to the exact same position every time, or if it's due to the imprecision in the position-sensing electronic scale. In any case, as I said, it's more of an annoyance than anything else, as I never use these for demanding work (and if you need accuracy greater than 0.01mm/0.0004", you should be using a micrometer anyway). ******************************************** ** Notes on "accuracy" versus "precision" ** ******************************************** Accuracy is the ability to get close to the actual, correct value. Precision is manifested in the ability to consistently obtain the same value on multiple measurings of the same dimension. To employ a comparison: in shooting, accuracy is how close you get to the bull's-eye, whereas precision is the tightness of your grouping (how close multiple shots are to each other). So, if you're measuring a 100.00mm gage block, accuracy would be how close your instrument comes to reading 100.00mm. If you measure 100.02mm, then you are accurate within 0.02mm. Precision is determined by making the same measurement multiple times. If, for example, at the conclusion of ten separate measurements, your instrument measures 100.02mm every time, then it is very precise. On the other hand, if it sometimes read 100.03mm and sometimes read 100.01mm, then your precision is +/- 0.01mm, thus your measurement is 100.02mm +/- 0.01mm. When it comes to metrology, precision is always more important than accuracy. The reason for this is that you can easily compensate for errors in accuracy: if you know how far off your instrument is (by calibrating it against a known dimensional standard), you can either re-calibrate it or simply add/subtract the known error to your measurements. However, errors in precision can only be dealt with terms of statistical probability (that's where dimensional tolerance really come in to play). ******************************************** - Michael |
Suggestions on Micrometer, Calipers??
What are some features to look for in a micrometer or caliper? Are the
ones at Harbor Freight worth considering? I have a $20 micrometer from Sears, but I think it may not be too accurate. I am looking to mainly measure items that are .1mm - .3mm in thickness (weekly use), but sometimes stuff that is larger (monthly or yearly). I wouldn't need to measure anything larger than 3"/75ish mm. I saw a 3 piece kit at Harbor Freight that has a 0-25mm micrometer, 25 - 50mm micrometer and 50 - 75 mm micrometer. Has anyone seen that one? What makes a Starett/Mitutuyo/etc. brand so much more better (expensive too)? "Grant Erwin" wrote in message ... I have over the last 15 years or so bought several lots of machinist tools, so I've gotten quite a few different things in my hands to look at. My main set of micrometers is a nice Lufkin 0-6" set in a wooden box, very chi-chi. However, when it was time for me to tool up to go do 2 quarters of machine shop classes at night school and leave my tools there in my locker, I took only tools that I felt I could live without because the risk of theft was very high. Among those tools was a 0-1" Craftsman Professional micrometer. I used that a lot in the lathe class, and grew to really like it. It seems to me (as big a snob as anyone) that it is made very well indeed, and appears to work perfectly. Later I sought out and found a 1-2" matching Craftsman Professional mic, and I like it too. Still later someone told me that these are made for Craftsman by Starrett, which would explain everything. The kicker is that with Craftsman stuff having gone so far downhill since the '70s, the older Craftsman Professional machinist tools go *cheap*. I paid the princely sum of $4 for my 1-2" mic on ebay. So my advice is, if you're starting out, you could do much worse than go find some Craftsman Professional stuff on ebay. Hi. Thanks for the suggestions. Would I need to look for only older Craftsman Professional, or any year of Craftsman Professional? Also, there are two kinds of calipers, which causes horrible confusion. One kind often has a little readout and is basically like a 6" rule, maybe a dial or digital caliper. The other kind has 2 legs, comes in inside, outside and hermaphrodite, and I find it very confusing that they are all called "calipers". Anyway, I have a whole bunch of the latter and if you're interested email me offline. I've been decluttering lately, which means selling stuff, and these are quite inexpensive. See: http://seattle.craigslist.org/tls/108149920.html GWE Kirkland, Washington Sorry to not know the differences in names. I am a rookie in all this. The kind I have is 6" wide with a dial gauge. I have seen those kind that look like an old compass with crooked legs. Me finding out what those are for is a whole other thread, so please don't worry about explaining what they are for. Thanks for the offer, but I will have to pass. Thank you. |
Suggestions on Micrometer, Calipers??
"Harold and Susan Vordos" wrote in message ... "JWho" wrote in message news:I%Iaf.516772$_o.377448@attbi_s71... What are some features to look for in a micrometer or caliper? Are the ones at Harbor Freight worth considering? I have a $20 micrometer from Sears, but I think it may not be too accurate. I am looking to mainly measure items that are .1mm - .3mm in thickness (weekly use), but sometimes stuff that is larger (monthly or yearly). I wouldn't need to measure anything larger than 3"/75ish mm. I saw a 3 piece kit at Harbor Freight that has a 0-25mm micrometer, 25 - 50mm micrometer and 50 - 75 mm micrometer. Has anyone seen that one? What makes a Starett/Mitutuyo/etc. brand so much more better (expensive too)? Thank you. The one thing you must understand is that calipers, vernier, dial, or digital, in NO way will be anywhere near as accurate as a micrometer----nor are they intended to be. Micrometers, even those that are not calibrated in tenths, are far more precise than are calipers------by design. See, I didn't know that. I was just using whichever one fit. One of the things you must do is make your decision based on your needs. If you are concerned about a thou, then don't rely on calipers. If you don't care if you are off a few tenths, a cheap micrometer will suffice. The more expensive measuring tools are generally more reliable, although that isn't a given. I bought a new Mitutoyo dial caliper that varied by .002", inside to outside measurements. That was excessive, and they were returned. I asked for a replacement, not a refund, for I have great faith in the Mitutoyo name, having used many of their measuring tools and finding them to be superior in some instances to Starrett, which I own almost exclusively. Bottom line: buy both, mics and calipers, if you can afford them. Each has a place, but it's important for you to understand which is proper for the application at hand. Harold How is Mitituyo pronounced?? Thanks for the information. That lets me know I need to buy a 25mm - 50mm micrometer and a 50mm - 75mm micrometer, or whatever would do such a job as a micrometer. I don't want SAE! I am tired of converting. Thanks. |
Suggestions on Micrometer, Calipers??
"Gunner" wrote in message ... On Fri, 4 Nov 2005 10:08:43 -0800, "Harold and Susan Vordos" wrote: "JWho" wrote in message news:I%Iaf.516772$_o.377448@attbi_s71... What are some features to look for in a micrometer or caliper? Are the ones at Harbor Freight worth considering? I have a $20 micrometer from Sears, but I think it may not be too accurate. I am looking to mainly measure items that are .1mm - .3mm in thickness (weekly use), but sometimes stuff that is larger (monthly or yearly). I wouldn't need to measure anything larger than 3"/75ish mm. I saw a 3 piece kit at Harbor Freight that has a 0-25mm micrometer, 25 - 50mm micrometer and 50 - 75 mm micrometer. Has anyone seen that one? What makes a Starett/Mitutuyo/etc. brand so much more better (expensive too)? Thank you. The one thing you must understand is that calipers, vernier, dial, or digital, in NO way will be anywhere near as accurate as a micrometer----nor are they intended to be. Micrometers, even those that are not calibrated in tenths, are far more precise than are calipers------by design. One of the things you must do is make your decision based on your needs. If you are concerned about a thou, then don't rely on calipers. If you don't care if you are off a few tenths, a cheap micrometer will suffice. The more expensive measuring tools are generally more reliable, although that isn't a given. I bought a new Mitutoyo dial caliper that varied by .002", inside to outside measurements. That was excessive, and they were returned. I asked for a replacement, not a refund, for I have great faith in the Mitutoyo name, having used many of their measuring tools and finding them to be superior in some instances to Starrett, which I own almost exclusively. Bottom line: buy both, mics and calipers, if you can afford them. Each has a place, but it's important for you to understand which is proper for the application at hand. Harold I work in machine shops as a machine tool repair tech. Given that most shops now days have few machinists..but lots of operators at lower pay scales..Chinese metrology equipment is very very common. Every calibrator Ive talked to says that 99.99% of Chinese mics etc etc will pass calibration every time, for at least 5 yrs of daily work, before they start getting worn out. Now if you are doing home stuff...that 5 yrs will translate into "grandchildrens bequest". If you are a pro..and need them to last for 30 yrs..by the big names. YMMV Gunner Hi. Thank you for the information. I won't use any of them daily, and probably not even weekly or monthly on the larger micrometers. Unfortunately, I have found out that even if you only need it one time, then you need it. :-( |
Suggestions on Micrometer, Calipers??
"Chuck Sherwood" wrote in message ... I work in machine shops as a machine tool repair tech. Given that most shops now days have few machinists..but lots of operators at lower pay scales..Chinese metrology equipment is very very common. Every calibrator Ive talked to says that 99.99% of Chinese mics etc etc will pass calibration every time, for at least 5 yrs of daily I have a set of chineese mics from enco and they work fine. When I first got them, I would measure something with a starret or B&S and the enco and they compared well. I enve tried a couple Jo blocks and they seemed right on. They work well and the price is right. I also use the cheap enco calipers for everyday work. I have better ones, but I don't cry if I drop the cheap ones. chuck From lurking on this group, I have seen several people mention "Enco". Is that an on-line store or is it a walk-in store like Harbor Freight. There is a Harbor Freight store near here, but I have never heard of Enco. What is a "Jo blocks"?? Thank you. |
Suggestions on Micrometer, Calipers??
"Rex B" wrote in message ... Chuck Sherwood wrote: I work in machine shops as a machine tool repair tech. Given that most shops now days have few machinists..but lots of operators at lower pay scales..Chinese metrology equipment is very very common. Every calibrator Ive talked to says that 99.99% of Chinese mics etc etc will pass calibration every time, for at least 5 yrs of daily I have a set of chineese mics from enco and they work fine. When I first got them, I would measure something with a starret or B&S and the enco and they compared well. I enve tried a couple Jo blocks and they seemed right on. They work well and the price is right. I also use the cheap enco calipers for everyday work. I have better ones, but I don't cry if I drop the cheap ones. I've had the same experience. The Enco mics get everyday use and I don't worry about them walking off. Hi. Thank you for sharing your experience. |
Suggestions on Micrometer, Calipers??
"Dave Lyon" wrote in message news:o_Paf.541319$xm3.343462@attbi_s21... I bought a new Mitutoyo dial caliper that varied by .002", inside to outside measurements. That was excessive, and they were returned. I asked for a replacement, not a refund, for I have great faith in the Mitutoyo name, having used many of their measuring tools and finding them to be superior in some instances to Starrett, which I own almost exclusively. I don't care for starrett mikes. Most of them have slanted lines which I find hard to read. My favorites are Brown and Sharp, followed closely by the more affordable Mitutoyo. Thank you for the warning. If I understand you correctly, the measurement marks do not go straight up and down. I didn't even know they made them with slanted lines, and I don't think I would like that. My cheap $20 Sears( Chinese) micrometer has straight up and down lines. Also, thanks for the information on Brown and Sharp. If you consider Mitutuyo affordable, then I don't even have to look for Brown and Sharp on Google. :-) |
Suggestions on Micrometer, Calipers??
"Chuck Sherwood" wrote in message ... My favorites are Brown and Sharp, followed closely by the more affordable Mitutoyo. I have heard that old Mitutoyo mics were great. Newer ones are not so great. That about about 7-8 years ago. Disclaimer: I don't own any Mitutoyo mics, but I do have some electronic calipers and I like them. Hi. Thanks for sharing your experience on that. |
Suggestions on Micrometer, Calipers??
"Grant Erwin" wrote in message ... We used to beat on this topic a lot back in the '90s. I have 3 6" calipers, all in like-new condition. One is Browne & Sharp, one is Starrett (those two are dial calipers) and the 3rd is Mitutoyo digital. The one I use the most? The Browne & Sharp. Great tool. Actually, they're all good. If I had to let go of one, though, it would be the Starrett. GWE Hi. Thanks again for sharing your experiences. |
Suggestions on Micrometer, Calipers??
"Harold and Susan Vordos" wrote in message ... "Dave Lyon" wrote in message news:o_Paf.541319$xm3.343462@attbi_s21... I bought a new Mitutoyo dial caliper that varied by .002", inside to outside measurements. That was excessive, and they were returned. I asked for a replacement, not a refund, for I have great faith in the Mitutoyo name, having used many of their measuring tools and finding them to be superior in some instances to Starrett, which I own almost exclusively. I don't care for starrett mikes. Most of them have slanted lines which I find hard to read. I'm not sure what Starrett mic's you've seen, but I have eight of them, not one has slanted lines. I don't like them slanted, either. I'm well pleased with the Starrett line, and I have several of their tools, including gage blocks and height gage. That, of course, excludes the Last Word indicator, which I also own. Those suckers should be taken to court for selling such a low life piece of garbage. It's an insult to their quality. I own several of their long travel indicators and like them just fine. Harold gauge blocks? height gauge? Last Word indicator? Every time I ask a question here, I have ten more questions pop up in my head on stuff I don't know. :-) PLEASE DON'T answer those questions, as I am trying to handle the micrometer problem for now. :-) Thank you. |
Suggestions on Micrometer, Calipers??
"D Murphy" wrote in message ... "JWho" wrote in news:I%Iaf.516772$_o.377448@attbi_s71: What are some features to look for in a micrometer or caliper? You've gotten some good advice but I'll throw in my .02. Features to look for in a micrometer to me would be: Carbide faces - They wear longer and stay flatter over time. Downside is that carbide chips easily, so if you aren't going to be careful and organized don't bother. "Tenths" vernier - Allows you to measure to .0001" Spindle lock - Allows you to reach into a machine, measure, engage the lock, then remove the micrometer so you can read it. The lever types are easiest to use, they also break quicker than the knurled ring around a collar type. I think I know what you mean on this one. My Sears (Chinese) micrometer has a lever. I didn't even know there was another kind, so thanks for pointing that out. Remember, you are dealing with a newbie here. :-) Adjustment for calibration - There are several schemes for this, the easiest to use are the type where the barrel is rotated by a small spanner wrench. The worst are the types where you have to remove the spindle, tweek it, then put it back together to see if you've done any good. I don't think my micrometer has any adjustability, but there is some screw on the bottom of my dial caliper. I don't know what it is for, though. That is another post, though. No need to worry about that. Slip mechanism - This would be either a friction thimble or a ratchet on the end of the thimble. I prefer a friction thimble for measuring while holding the mic in my hand. I prefer the ratchet thimble for use in a micrometer stand. A micrometer stand will allow you to measure more repeatably and more accurately. Micrometer stand? I had never heard of such a thing. I guess I will have to read up on that as well. Thimble diameter - Often an overlooked feature. I like my Starett because it's light and skinny (plus it was the first one I bought). OTOH, I don't like it for measuring "tenths". As I get older it's harder to read, plus it's prone to parallax error. A fat thimble like the one on my Helios gives me more consistant readings as the lines are spaced further apart and easier on my failing eyesight. If you aren't old now, just wait. Calipers are a different matter. First you need to decide which type you want; verniers, dial, or digital. In general: Verniers - they are the most accurate and repeatable of the bunch. They also will last damn near forever if used carefully and taken care of. They can be hard to read, and quick reading is not a feature built into these. Starrett 123 verniers are the best bar none. They are also very expensive. Mitutoyo makes a decent pair of six inch ones that can be bought new today. They are lighter and more frail than the Starrett, plus they aren't flush reading so parallax error can be a problem. What would be an example of a vernier?? Is this the one that looks like a compass with legs going out or legs going in?? Dial Calipers - The features I look for a Four way measurement. They can measure OD using the main jaws. ID's using the top jaws. Depth using the rod that comes out of the end. And steps using the outside edge of the fixed jaw and the outside edge of the moveable jaw. DEPTH!? I went and checked my dial guage, and it has that! I just thought the end was shaped funny. .100" per revolution dial. Some calipers move .200" per revolution of the dial, these are harder to read. Covered gear rack - dial calipers have a gear rack that drives the clockworks when the moveable jaw slides. If chip get in there, the caliper at the very least can jump teeth resulting in an off center zero. At worst the gears become damaged and the caliper will no longer be accurate through out the range. I'll be sure to check this area and keep it clean in the future. Quality - They can range from nearly as good as a vernier to nearly worthless. I've used them all over the years. The Brown and Sharpes are the best. They are also the same as the Etalon and the Tesa dial calipers. The Etalon ones are usually more expensive because they have a pretty horse stamped on them;) If you go with the B&S calipers make sure they are the ones that say Swiss made. Mitutoyo is a decent second choice. They are a little light and not as smooth but overall they are OK. The Starretts aren't worth the money IMO. They are too soft and I don't like the feel of them. You could buy a Peacock brand (cheap Japanese) and get the same quality for a lot less. I don't like the Chinese ones at all. Dial calipers need to have precision gears, and quality assembly. They Stainless Steel should be quality and well hardened. Those qualities don't exist in Chinese dial calipers. Digital Calipers - You can pretty much buy a Mitutoto, Starrett, Brown and Sharpe, Etalon, or Tesa and end up with a damn nice tool. That being said, if your budget is tight the Chinese digital calipers aren't bad at all for the money. Buy them on Ebay and you'll save some money. The big brands are more coolant proof, have harder jaws, and better battery life. But if you can be careful with the Chinese ones, they are about as accurate. Just remove the battery between uses. They suck juice in a big way just sitting there turned off. Some don't turn off automatically either, but the difference in battery life is small. Only buy NEW calipers on Ebay. Micrometers are another matter, but calipers are easily damaged. I saw a $16 model on the Harbor Freight website that has an electonic read out that shows in metric or SAE. Since I don't use it very often, and what I use it for deosn't have to be very accurate, I think I will give it a try. My current one is SAE and I only work on metric stuff, so I want one that is metric. I'll be sure to take out the battery. Thanks for the tip. Are the ones at Harbor Freight worth considering? No for the micrometers, and maybe for digital calipers. You can buy a perfectly good high quality used micrometer on Ebay for about what you'd pay for a Chinese one new. Starretts usually command a slightly higher price due to the name. But 0-1" Starretts are so common though the price is usually 1/3 - 1/4 of new. Mitutoyo's are decent and often go for cheap. But if you are savvy and patient you can snag a really nice micrometer for next to nothing. What you want to keep an eye out for are older Helios micrometers, newer Tesa, and Brown & Sharpes. Alos look for older MG brand, I bought one of these NOS, never used. It's a Lufkin rebranded. MG later became General brand. Don't touch those. The one you want will have carbide, tenths, and a unique friction thimble that is at the top of the thimble, plus a knurled ring lock. These are stamped "Made in USA". They were sold mainly in hobby stores, but they are Lufkin. I paid $3.00 for mine plus shipping. But be careful, some are cheap hobby type and are nearly worthless. If it doesn't have the above features don't bid. Also look for Mitutoyo "106" micrometers. They have a non rotating anvil and the model# starts with "106-" Hell here is a 1-2" http://cgi.ebay.com/MITUTOYO-MICROMETERS-1-2-INCH-75- OFF_W0QQitemZ7554844037QQcategoryZ92085QQssPageNam eZWD1VQQrdZ1QQcmdZViewI tem or http://tinyurl.com/7uwbp People don't know what these are and they sell cheap! Also look for JT Slocomb, Lufkin, and Etalon. Etalons usually sell for big bucks. I have a $20 micrometer from Sears, but I think it may not be too accurate. Older Craftsmen micrometers can be made by Starrett, Mitutoyo, or Helios. All very good. The new ones aren't worth a damn. I am looking to mainly measure items that are .1mm - .3mm in thickness (weekly use), but sometimes stuff that is larger (monthly or yearly). I wouldn't need to measure anything larger than 3"/75ish mm. I saw a 3 piece kit at Harbor Freight that has a 0-25mm micrometer, 25 - 50mm micrometer and 50 - 75 mm micrometer. Has anyone seen that one? They are probably like these http://tinyurl.com/9u5q3 The ones they have at the local Harbor Freight is $40 and they are green. I don't see them on the website anymore. They are made by Cen-Tech. Instead of Chinese look for the ones made in Poland. They are really quite nice - http://tinyurl.com/dl8vx They are usually called VIS or VIN brand. Sometimes they just say Poland. I would try to get used brand name first. At least for the 0-1". You will use it the most. Here is a guy with a bunch of new Mitutoyo digit mics listed http://search.ebay.com/_W0QQsassZadsotlarQQhtZ-1 Looks like they can be had for ten bucks plus shipping. Why buy Chinese? What makes a Starett/Mitutuyo/etc. brand so much more better (expensive too)? They are more accurate. They are made with better materials, have better fit, finish and feel. Often the frames and spindle are harder. Plus they stand behind what they sell. You can send tham a broken tool and they will fix it, or you can order parts from them. The tools are also traceable to NIST. -- Dan Thanks again for all the information, plus taking the time to write up such a thorugh reply. I sincerely appreciate it. |
Suggestions on Micrometer, Calipers??
"DeepDiver" wrote in message ... "D Murphy" wrote in message ... "JWho" wrote in news:I%Iaf.516772$_o.377448@attbi_s71: What are some features to look for in a micrometer or caliper? Digital Calipers - snip if your budget is tight the Chinese digital calipers aren't bad at all for the money. Buy them on Ebay and you'll save some money. Are the ones at Harbor Freight worth considering? No for the micrometers, and maybe for digital calipers. Dan Excellent post Dan. I would just add a bit of clarifying info to the last part about Harbor Freight, as you addressed the issue of micrometers, but forgot to elaborate on the calipers. The electronic digital calipers sold at harbor Freight are essentially the same as all the Chinese import digital calipers sold on Ebay. So if you want one (or several in different sizes), you can probably get them cheaper and more conveniently at your local HF store (if you have one nearby). I have a 6" Mitutoyo digital caliper that is very accurate *AND* very precise (see below for why these terms are different). I also have a couple of the HF digital calipers in different sizes for the times I need smaller or larger (I bought a new 12" HF digital caliper for less than $40 in the store, whereas even a used 12" Mitutoyo of unknown condition will sell on Ebay for well over $200). I also will turn to the HF calipers for situations where I don't want to risk damage to my Mitutoyo caliper. I find the HF calipers are accurate enough for most hobby/small shop purposes. What annoys me the most about them is their apparent lack of precision: if I close the jaws and zero the display, then open and close the jaws, sometimes the "zero" position will read 0.01mm or -0.01mm. I'm not sure if it has to do with an imperfection in the mechanical construction which prevents the jaws from closing to the exact same position every time, or if it's due to the imprecision in the position-sensing electronic scale. In any case, as I said, it's more of an annoyance than anything else, as I never use these for demanding work (and if you need accuracy greater than 0.01mm/0.0004", you should be using a micrometer anyway). ******************************************** ** Notes on "accuracy" versus "precision" ** ******************************************** Accuracy is the ability to get close to the actual, correct value. Precision is manifested in the ability to consistently obtain the same value on multiple measurings of the same dimension. To employ a comparison: in shooting, accuracy is how close you get to the bull's-eye, whereas precision is the tightness of your grouping (how close multiple shots are to each other). So, if you're measuring a 100.00mm gage block, accuracy would be how close your instrument comes to reading 100.00mm. If you measure 100.02mm, then you are accurate within 0.02mm. Precision is determined by making the same measurement multiple times. If, for example, at the conclusion of ten separate measurements, your instrument measures 100.02mm every time, then it is very precise. On the other hand, if it sometimes read 100.03mm and sometimes read 100.01mm, then your precision is +/- 0.01mm, thus your measurement is 100.02mm +/- 0.01mm. When it comes to metrology, precision is always more important than accuracy. The reason for this is that you can easily compensate for errors in accuracy: if you know how far off your instrument is (by calibrating it against a known dimensional standard), you can either re-calibrate it or simply add/subtract the known error to your measurements. However, errors in precision can only be dealt with terms of statistical probability (that's where dimensional tolerance really come in to play). ******************************************** - Michael Thank you for all the information. I appreciate you taking the time to write that up. Precision vs. accuracy is one of the few things I remember from school. Precision was sown as throwing the darts all in one small area. Accuracy was shown as hitting the bullseye. Precision and accuracy was shown as throwing all the darts in the bullseye. I am going to do like you suggested and just get a set of calipers from Harbor Freight. I don't need them to be very accurate, just metric. I currently have a 6" dial gauge caliper made by O.E.M (that's what it said on the pacakge) from Auto Zone. It seems to work OK, but it is not metric, and I only work on/like metric. Thanks! |
Suggestions on Micrometer, Calipers??
According to JWho :
What are some features to look for in a micrometer or caliper? Are the "Grant Erwin" wrote in message ... [ ... ] So my advice is, if you're starting out, you could do much worse than go find some Craftsman Professional stuff on ebay. Hi. Thanks for the suggestions. Would I need to look for only older Craftsman Professional, or any year of Craftsman Professional? This one I'll leave to Grant, as I am only familiar with the ones which were made by Scherr Tumico for Sears to bear the Craftsman name. Also, there are two kinds of calipers, which causes horrible confusion. One kind often has a little readout and is basically like a 6" rule, maybe a dial or digital caliper. The other kind has 2 legs, comes in inside, outside and hermaphrodite, and I find it very confusing that they are all called "calipers". Anyway, I have a whole bunch of the latter and if you're interested email me offline. I've been decluttering lately, which means selling stuff, and these are quite inexpensive. See: http://seattle.craigslist.org/tls/108149920.html GWE Kirkland, Washington Sorry to not know the differences in names. I am a rookie in all this. The kind I have is 6" wide with a dial gauge. A dial "readout", I think is the better term. This is commonly called a "dial caliper". I have seen those kind that look like an old compass with crooked legs. Me finding out what those are for is a whole other thread, so please don't worry about explaining what they are for. Thanks for the offer, but I will have to pass. I've already mentioned this in another branch of the thread, so I won't duplicate that now. Good Luck, DoN. -- Email: | Voice (all times): (703) 938-4564 (too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html --- Black Holes are where God is dividing by zero --- |
Suggestions on Micrometer, Calipers??
In article I%Iaf.516772$_o.377448@attbi_s71, JWho says...
What are some features to look for in a micrometer or caliper? Other folks have given some excellent advice, I will add in that you can often get used micrometers from estate sales and off of ebay. Often they are in very good shape and make an economical start for the beginner. You need to estimate what kind of tolerances you will be working to. Dial or digital calipers are very handy and will come very close to micrometer accuracy when brand new, Harold's caveats take in stride. When they age they will be off by a thou or three. The mitutoyo six inch digital calipers would give good service for a lont time. Do NOT buy the starrett digial calipers. If you happen onto a used set of dial calipers you may find the rack full of swarf and this can be set straight if you are good at watch repair or the like. This is how I got my pair of 4" mitutoyo dial calipers and they are still my all around workhorses as long as I know they are +/- 0.002 or so. For relative work they're nice because I'm not afraid of dinging them. I have a good set of starrett dial calipers which a lot of folks consider to be a non-starter given the open rack, but I *like* the feel. I also have recently gotten a 12 inch pair of Mitutoyo digital calipers (that was last Xmas) because I know those things are quite bulletproof because they used them in the production shop I formerly worked in and they got beaten beyond belief and kept coming back for more. Any name brand micrometer like Lufkin, Starrett, B&S, and so on will give good service, and good condition used ones can be had for about the same price as brand new import ones, if you prefer name tools. Jim -- ================================================== please reply to: JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com ================================================== |
Suggestions on Micrometer, Calipers??
"JWho" wrote in news:txcbf.524574$_o.129814@attbi_s71:
What is a "Jo blocks"?? Johannson blocks. Otherwise known as gage blocks. Johannson was the inventor of the concept so they became known as "Johannson's blocks", which got shortened to "Jo blocks". Enough history. Gage blocks are the master mechanical reference by which all mechanical measuring devices are checked. In simple termes they are square or rectangular blocks made out of either high chrome alloy steel, carbide or ceramic. A typical "inch" set would have 82 blocks of different thicknesses. These blocks can be combined to make up any length required. Then you can check your measuring device against this "known" length. Gage blocks are machined, ground, hardened, stabilized, then lapped to final size. Since gage blocks are the master mechanical reference, they must be checked by a non mechanical means. Typically a gage block interferometer is used. Where a known light scource is "split" into it's known wave lengths. These wave lengths have a known thickness and they are then compared to the gage block being measured. The temperature and humidity is closely controlled, typically the block is measured in a sealed chamber, and the interferometer is in a clean room, isolated from vibration. With a good interferometer, you can actually measure the curvature of the earth on the block being measured. Nothing can be truly "flat" here on earth. This is an over simplified explanation but it'll do. Or read this - http://inms-ienm.nrc-cnrc.gc.ca/en/research/green.pdf At any rate, the gage blocks are sorted by class. There are several different classification systems, but they all work the same. The lower the number or letter, the closer tolerance the gage block is. Since gage blocks are usually used in combination with other gage blocks to make up a known length, the tolerances of each block stack up to create a larger error. Grade 2 or 3 or B or C are typically known as "shop grade". They would be used in the shop for set-up, sine bars, etc. where the stacked up tolerances won't affect the work to the point where it would be a problem. But even shop grade blocks are usually good to .00005" or ..0001". A pretty tight tolerance no matter how you look at it. But it's not good enough for calibration of measuring tools. The company I work for makes gage blocks to a grade better than JIS 00. They call it 000. the tolerance is .03 microns. Which is .0000012". Here are a couple of links - http://catalog.starrett.com/catalog/...?NodeNum=24926 http://www.tsugami.co.jp/product/other/GAGE/GB.pdf -- Dan |
Suggestions on Micrometer, Calipers??
"Harold and Susan Vordos" wrote in
: "D Murphy" wrote in message ... good stuff snipped-------- They are more accurate. They are made with better materials, have better fit, finish and feel. Often the frames and spindle are harder. Plus they stand behind what they sell. You can send tham a broken tool and they will fix it, or you can order parts from them. The tools are also traceable to NIST. Dan Well done, Dan. Thanks Harold. I was trying to give a good thorough explanation and share some experience. I might have mentioned before that in my work I get to use nearly every brand of measuring tool at some point. The way I see it, when whether or not a customer accepts my $200,000.00 to $500,000.00 dollar machine tool, comes down to his measuring parts that I'm making. I'd better be interested in how he is measuring the parts. Usually the customers know what they are doing, but sometimes you'd be amazed. I know a lot of people would say, "well it's just for hobby use so buy a cheap Chinese micrometer." I can see their point. But if the hobby becomes more serious, or you decide to some very tight tolerance work, or you decide that you like the hobby enough to make the jump into a career, then you will need the better tools. Why not buy the quality tool on Ebay where they can be had for pennies on the dollar? Often new and unused. Plus if you decide to sell your tools someday (blasphemy), quality tools have a better residual value. I have a Mitutoyo carbide tip blade mike that I bought twenty-some years ago. Recently I came across the receipt for it while cleaning ny tool box. I could sell it today on Ebay and would get ten to twenty bucks less than I paid for it. Somehow I doubt that will be the case for a no name Chinese blade mike. I also collect antique machinist tools. I recently bought a 100+ year old Brown & Sharpe 0-1". After calibrating it, it is still spot on throughout its range. Same with a Starrett that is nearly as old. I could use these tools tomorrow without a worry about whether or not they are accurate. -- Dan |
Suggestions on Micrometer, Calipers??
Harold and Susan Vordos wrote:
"Dave Lyon" wrote in message news:o_Paf.541319$xm3.343462@attbi_s21... I bought a new Mitutoyo dial caliper that varied by .002", inside to outside measurements. That was excessive, and they were returned. I asked for a replacement, not a refund, for I have great faith in the Mitutoyo name, having used many of their measuring tools and finding them to be superior in some instances to Starrett, which I own almost exclusively. I don't care for starrett mikes. Most of them have slanted lines which I find hard to read. I'm not sure what Starrett mic's you've seen, but I have eight of them, not one has slanted lines. I don't like them slanted, either. I'm well pleased with the Starrett line, and I have several of their tools, including gage blocks and height gage. That, of course, excludes the Last Word indicator, which I also own. Those suckers should be taken to court for selling such a low life piece of garbage. It's an insult to their quality. I own several of their long travel indicators and like them just fine. Harold Mics, from 0-6" I've a couple Tesas which I favor the most, even with slanted lines, a couple Mitus, don't like the 0-1 cause of the ratchet location but it's accurate, a Fowler that sure looks like a Mitutoyo, a couple Starretts which are right up there, a nice B&S, and a Craftsmanwhich seems okay but is same range as a Starrett right next to it. Which would you grab? From 6-12" I have 2 sets of Tumico tubular mics. A bit of a pain to set up each time, but they work well. Don't have any what I would call junk mics. No offence to anyone spouting of the quality of whatever Harbor Salvage has this week, but at this stage I don't forsee buying any more mics. Unless one of them super-steal-deals falls in my lap. Calipers, still have my first $39.95 0-6" Tesa dials which are in honored retirement. They only found the floor once during a long and distinguished career. Have a couple or three 6" dials, 3 8" dials, a 12" dial, and 1 6" digi, which are all Mitutoyo. The digi is used rarely for metric measuring. Some would argue, and I agree that a mic is the better choice for close measurment, BUT a good hand *can* check within temths with a good caliper (dials) if properly calibrated. Sometimes it may be the only option available. My picks for most used and favored are the 0-1" Tesa mic used daily for over 35 years and 8" dial Mitutoyo caliper. They feel right and work right. michael Harold, why in the #### do you have a Last Word indicator? I got one with a bunch of stuff once and found a sucker to take it. And I didn't have to pay him! |
Suggestions on Micrometer, Calipers??
jim rozen wrote:
In article I%Iaf.516772$_o.377448@attbi_s71, JWho says... What are some features to look for in a micrometer or caliper? Other folks have given some excellent advice, I will add in that you can often get used micrometers from estate sales and off of ebay. Often they are in very good shape and make an economical start for the beginner. I was thinking the same thing. I've had occasion to get some tools at 2 different estate sales. I don't recall tit for tat, but the value I got was excellent. At one I got, among other things, a small Kennedy chest with the 2-drawer under it. Inside the boxes were several types of Starrett mics, ID, OD, depth. They all had the original cert of accuracy with them and there were absolutely no chips in any of the drawers. I also got several things that don't always make it on the need to buy list, but are needed and/or wanted. michael You need to estimate what kind of tolerances you will be working to. Dial or digital calipers are very handy and will come very close to micrometer accuracy when brand new, Harold's caveats take in stride. When they age they will be off by a thou or three. The mitutoyo six inch digital calipers would give good service for a lont time. Do NOT buy the starrett digial calipers. If you happen onto a used set of dial calipers you may find the rack full of swarf and this can be set straight if you are good at watch repair or the like. This is how I got my pair of 4" mitutoyo dial calipers and they are still my all around workhorses as long as I know they are +/- 0.002 or so. For relative work they're nice because I'm not afraid of dinging them. I have a good set of starrett dial calipers which a lot of folks consider to be a non-starter given the open rack, but I *like* the feel. I also have recently gotten a 12 inch pair of Mitutoyo digital calipers (that was last Xmas) because I know those things are quite bulletproof because they used them in the production shop I formerly worked in and they got beaten beyond belief and kept coming back for more. Any name brand micrometer like Lufkin, Starrett, B&S, and so on will give good service, and good condition used ones can be had for about the same price as brand new import ones, if you prefer name tools. Jim |
Suggestions on Micrometer, Calipers??
One thing to get is a Starrett catalog, doesn't matter what year. If
you thumb through it, you'll find a lot of your questions answered. I haven't gotten one for a number of years, but they used to be free at the distributors. Starrett now has a website, you might be able to sign up there for a catalog or at least browse the range of tools that they handle. Looking is cheap. Might be able to find a local distributor, too. Starrett also used to have a small book for the education of apprentices and the like, you might see if you can find one of those. I have one that I got on a close-out, wasn't expensive at list, was a steal when I got it. Lots of tables and explanations in there. Stan |
Suggestions on Micrometer, Calipers??
"DoN. Nichols" wrote in message rvers.com... According to JWho : What are some features to look for in a micrometer or caliper? Are the "Grant Erwin" wrote in message ... [ ... ] So my advice is, if you're starting out, you could do much worse than go find some Craftsman Professional stuff on ebay. Hi. Thanks for the suggestions. Would I need to look for only older Craftsman Professional, or any year of Craftsman Professional? This one I'll leave to Grant, as I am only familiar with the ones which were made by Scherr Tumico for Sears to bear the Craftsman name. Also, there are two kinds of calipers, which causes horrible confusion. One kind often has a little readout and is basically like a 6" rule, maybe a dial or digital caliper. The other kind has 2 legs, comes in inside, outside and hermaphrodite, and I find it very confusing that they are all called "calipers". Anyway, I have a whole bunch of the latter and if you're interested me offline. I've been decluttering lately, which means selling stuff, and these are quite inexpensive. See: http://seattle.craigslist.org/tls/108149920.html GWE Kirkland, Washington Sorry to not know the differences in names. I am a rookie in all this. The kind I have is 6" wide with a dial gauge. A dial "readout", I think is the better term. This is commonly called a "dial caliper". I have seen those kind that look like an old compass with crooked legs. Me finding out what those are for is a whole other thread, so please don't worry about explaining what they are for. Thanks for the offer, but I will have to pass. I've already mentioned this in another branch of the thread, so I won't duplicate that now. Good Luck, DoN. -- Email: | Voice (all times): (703) 938-4564 (too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html --- Black Holes are where God is dividing by zero --- Hi. Thanks for the additional information. |
Suggestions on Micrometer, Calipers??
"D Murphy" wrote in message ... "JWho" wrote in news:txcbf.524574$_o.129814@attbi_s71: What is a "Jo blocks"?? Johannson blocks. Otherwise known as gage blocks. Johannson was the inventor of the concept so they became known as "Johannson's blocks", which got shortened to "Jo blocks". Enough history. Gage blocks are the master mechanical reference by which all mechanical measuring devices are checked. In simple termes they are square or rectangular blocks made out of either high chrome alloy steel, carbide or ceramic. A typical "inch" set would have 82 blocks of different thicknesses. These blocks can be combined to make up any length required. Then you can check your measuring device against this "known" length. Gage blocks are machined, ground, hardened, stabilized, then lapped to final size. Since gage blocks are the master mechanical reference, they must be checked by a non mechanical means. Typically a gage block interferometer is used. Where a known light scource is "split" into it's known wave lengths. These wave lengths have a known thickness and they are then compared to the gage block being measured. The temperature and humidity is closely controlled, typically the block is measured in a sealed chamber, and the interferometer is in a clean room, isolated from vibration. With a good interferometer, you can actually measure the curvature of the earth on the block being measured. Nothing can be truly "flat" here on earth. This is an over simplified explanation but it'll do. Or read this - http://inms-ienm.nrc-cnrc.gc.ca/en/research/green.pdf At any rate, the gage blocks are sorted by class. There are several different classification systems, but they all work the same. The lower the number or letter, the closer tolerance the gage block is. Since gage blocks are usually used in combination with other gage blocks to make up a known length, the tolerances of each block stack up to create a larger error. Grade 2 or 3 or B or C are typically known as "shop grade". They would be used in the shop for set-up, sine bars, etc. where the stacked up tolerances won't affect the work to the point where it would be a problem. But even shop grade blocks are usually good to .00005" or .0001". A pretty tight tolerance no matter how you look at it. But it's not good enough for calibration of measuring tools. The company I work for makes gage blocks to a grade better than JIS 00. They call it 000. the tolerance is .03 microns. Which is .0000012". Here are a couple of links - http://catalog.starrett.com/catalog/...?NodeNum=24926 http://www.tsugami.co.jp/product/other/GAGE/GB.pdf -- Dan Hi. Thank you for the additional information. I appreciate it. |
Suggestions on Micrometer, Calipers??
wrote in message oups.com... One thing to get is a Starrett catalog, doesn't matter what year. If you thumb through it, you'll find a lot of your questions answered. I haven't gotten one for a number of years, but they used to be free at the distributors. Starrett now has a website, you might be able to sign up there for a catalog or at least browse the range of tools that they handle. Looking is cheap. Might be able to find a local distributor, too. Starrett also used to have a small book for the education of apprentices and the like, you might see if you can find one of those. I have one that I got on a close-out, wasn't expensive at list, was a steal when I got it. Lots of tables and explanations in there. Stan Hi. Thanks for the suggestion. I will look through their online catalog. |
Suggestions on Micrometer, Calipers??
"michael" wrote in message ... Harold and Susan Vordos wrote: "Dave Lyon" wrote in message news:o_Paf.541319$xm3.343462@attbi_s21... I bought a new Mitutoyo dial caliper that varied by .002", inside to outside measurements. That was excessive, and they were returned. I asked for a replacement, not a refund, for I have great faith in the Mitutoyo name, having used many of their measuring tools and finding them to be superior in some instances to Starrett, which I own almost exclusively. I don't care for starrett mikes. Most of them have slanted lines which I find hard to read. I'm not sure what Starrett mic's you've seen, but I have eight of them, not one has slanted lines. I don't like them slanted, either. I'm well pleased with the Starrett line, and I have several of their tools, including gage blocks and height gage. That, of course, excludes the Last Word indicator, which I also own. Those suckers should be taken to court for selling such a low life piece of garbage. It's an insult to their quality. I own several of their long travel indicators and like them just fine. Harold Mics, from 0-6" I've a couple Tesas which I favor the most, even with slanted lines, a couple Mitus, don't like the 0-1 cause of the ratchet location but it's accurate, a Fowler that sure looks like a Mitutoyo, a couple Starretts which are right up there, a nice B&S, and a Craftsmanwhich seems okay but is same range as a Starrett right next to it. Which would you grab? From 6-12" I have 2 sets of Tumico tubular mics. A bit of a pain to set up each time, but they work well. Don't have any what I would call junk mics. No offence to anyone spouting of the quality of whatever Harbor Salvage has this week, but at this stage I don't forsee buying any more mics. Unless one of them super-steal-deals falls in my lap. Calipers, still have my first $39.95 0-6" Tesa dials which are in honored retirement. They only found the floor once during a long and distinguished career. Have a couple or three 6" dials, 3 8" dials, a 12" dial, and 1 6" digi, which are all Mitutoyo. The digi is used rarely for metric measuring. Some would argue, and I agree that a mic is the better choice for close measurment, BUT a good hand *can* check within temths with a good caliper (dials) if properly calibrated. Sometimes it may be the only option available. My picks for most used and favored are the 0-1" Tesa mic used daily for over 35 years and 8" dial Mitutoyo caliper. They feel right and work right. michael Harold, why in the #### do you have a Last Word indicator? I got one with a bunch of stuff once and found a sucker to take it. And I didn't have to pay him! Hi. Thanks for the additional information. From everyone's help, it looks like I may need to check on eBay for a used micrometer. I don't use one often nough to justify the cost of a new, high quality, name brand model. Thanks again. |
Suggestions on Micrometer, Calipers??
"D Murphy" wrote in message ... "Harold and Susan Vordos" wrote in : "D Murphy" wrote in message ... good stuff snipped-------- They are more accurate. They are made with better materials, have better fit, finish and feel. Often the frames and spindle are harder. Plus they stand behind what they sell. You can send tham a broken tool and they will fix it, or you can order parts from them. The tools are also traceable to NIST. Dan Well done, Dan. Thanks Harold. I was trying to give a good thorough explanation and share some experience. I might have mentioned before that in my work I get to use nearly every brand of measuring tool at some point. The way I see it, when whether or not a customer accepts my $200,000.00 to $500,000.00 dollar machine tool, comes down to his measuring parts that I'm making. I'd better be interested in how he is measuring the parts. Usually the customers know what they are doing, but sometimes you'd be amazed. I know a lot of people would say, "well it's just for hobby use so buy a cheap Chinese micrometer." I can see their point. But if the hobby becomes more serious, or you decide to some very tight tolerance work, or you decide that you like the hobby enough to make the jump into a career, then you will need the better tools. Why not buy the quality tool on Ebay where they can be had for pennies on the dollar? Often new and unused. Plus if you decide to sell your tools someday (blasphemy), quality tools have a better residual value. I have a Mitutoyo carbide tip blade mike that I bought twenty-some years ago. Recently I came across the receipt for it while cleaning ny tool box. I could sell it today on Ebay and would get ten to twenty bucks less than I paid for it. Somehow I doubt that will be the case for a no name Chinese blade mike. I also collect antique machinist tools. I recently bought a 100+ year old Brown & Sharpe 0-1". After calibrating it, it is still spot on throughout its range. Same with a Starrett that is nearly as old. I could use these tools tomorrow without a worry about whether or not they are accurate. -- Dan I think I am going to look on eBay for a used name brand micrometer. Is there some way to check to see if it is accurate? Do they come with a metal bar that is .5" or 1" exactly or something like that?? I thought I saw something in a set at Harbor Freight. Is a micrometer adjustable to get it back to accurate? I'd hate to buy one off eBay and it be inaccurate. Also, there are so many different models that it is confusing. If I get one off eBay, it won't be a Chinese one. I can just go get a new one from Harbor Freight instead of eBay. Thanks. |
Suggestions on Micrometer, Calipers??
"jim rozen" wrote in message ... In article I%Iaf.516772$_o.377448@attbi_s71, JWho says... What are some features to look for in a micrometer or caliper? Other folks have given some excellent advice, I will add in that you can often get used micrometers from estate sales and off of ebay. Often they are in very good shape and make an economical start for the beginner. You need to estimate what kind of tolerances you will be working to. Dial or digital calipers are very handy and will come very close to micrometer accuracy when brand new, Harold's caveats take in stride. When they age they will be off by a thou or three. The mitutoyo six inch digital calipers would give good service for a lont time. Do NOT buy the starrett digial calipers. If you happen onto a used set of dial calipers you may find the rack full of swarf and this can be set straight if you are good at watch repair or the like. This is how I got my pair of 4" mitutoyo dial calipers and they are still my all around workhorses as long as I know they are +/- 0.002 or so. For relative work they're nice because I'm not afraid of dinging them. I have a good set of starrett dial calipers which a lot of folks consider to be a non-starter given the open rack, but I *like* the feel. I also have recently gotten a 12 inch pair of Mitutoyo digital calipers (that was last Xmas) because I know those things are quite bulletproof because they used them in the production shop I formerly worked in and they got beaten beyond belief and kept coming back for more. Any name brand micrometer like Lufkin, Starrett, B&S, and so on will give good service, and good condition used ones can be had for about the same price as brand new import ones, if you prefer name tools. Jim -- ================================================== please reply to: JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com ================================================== Hi. Thanks for the information. Of all the tools I mentioned, I can make the most use out of a 25mm - 50mm (if that is the normal range) micrometer. I am going to start looking on eBay for the brand names you and others have mentioned. If a used one can be checked for accuracy, then I would rather have a used name brand than a new Harbor Freight one, if the price is not too much more. |
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