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Metalworking (rec.crafts.metalworking) Discuss various aspects of working with metal, such as machining, welding, metal joining, screwing, casting, hardening/tempering, blacksmithing/forging, spinning and hammer work, sheet metal work. |
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#1
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I've used both of them, and find that the end mill holders are great when
you are using cutters with "weldon" flats on them. I'm sure if you want to grind a flat on all of your end mills then the holder will work fine. I am kinda cheap and find that you can buy double-end end mills for lesss than you can buy single-end end mills and they are usually too long to fit in the collet type holders. I can't really comment on the accuracy, they have both performed adequately for me. "Keith Marshall" wrote in message .com... BTW the mill is the mini-bench top unit sold by Harbor Freight. I made the "Mistake" of dropping in on the store in South Carolina :-) I seem to recall a friend telling me they have an outlet/surplus store somewhere in SC. Is that the one you're talking about and if so would you mind telling me where it is? Best Regards, Keith Marshall "The universe is full of magical things, patiently waiting for our wits to grow sharper." -Eden Phillpotts, A Shadow Passes, 1934 "Bradford Chaucer" wrote in message ... I just acquired am benchtop vertical mill that takes R8 colletts. It comes with a drill chuck which I know is not advised for milling. I have seen sets of both R8 colletts and R8 endmill holders. The difference as I see it is that the endmill holder protrudes from the end of the sleeve more than the collett does and it has a set screw for clamping on the flat on an end mill. My question is whether a collett is sufficient for holding endmills or am I advised to opt for the end mill holders?? BTW the mill is the mini-bench top unit sold by Harbor Freight. I made the "Mistake" of dropping in on the store in South Carolina :-) Anyone have any comments or suggestions for improving tweaking this unit (aside from you shouldn't have bought it!!) |
#2
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Some have said that on *really* heavy work and end mill can be
"sucked" out of a collet - a small amount, but enought to ruin a precise job. I have not seen this, but also don't anything super heavy. One advantage of holders is that you would not have to mess with the drawbar. On my mill I have to flip up the pully cover to change collets. Having said this, I still use collets - I'm not that lazy yet ;-) |
#3
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On Wed, 06 Aug 2003 22:54:44 GMT, Bradford Chaucer wrote:
My question is whether a collett is sufficient for holding endmills or am I advised to opt for the end mill holders?? End mill holders are designed to hold end mills. Collets are workholding devices. That said, you can use a collet to hold an end mill. The problem is that there's no way to lock the end mill in the collet to prevent it from sucking out while cutting. That could ruin a work piece in which you'd invested a lot of time. You can probably get away with it indefinitely on a small machine taking light cuts, but it is something to consider. Gary |
#4
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Collets are more convenient, and clamp with less potential 'runout', but
do not hold the cutter as securely as an end mill holder. Sooner or later you will likely have a collet slip under the cutting force of the mill. This can (and likely will) cause damage to workpiece and or cutter, and could cause damage to the operator or machine. Unless you confine yourself to making very light cuts, end mill holders are more dependable in the long run. That said, many just use collets with only rare problems. I HAVE had collets slip, but I still use them on occasion (odd cutter shank sizes, etc.), though I prefer end mill holders. Dan Mitchell ========== Bradford Chaucer wrote: I just acquired am benchtop vertical mill that takes R8 colletts. It comes with a drill chuck which I know is not advised for milling. I have seen sets of both R8 colletts and R8 endmill holders. The difference as I see it is that the endmill holder protrudes from the end of the sleeve more than the collett does and it has a set screw for clamping on the flat on an end mill. My question is whether a collett is sufficient for holding endmills or am I advised to opt for the end mill holders?? BTW the mill is the mini-bench top unit sold by Harbor Freight. I made the "Mistake" of dropping in on the store in South Carolina :-) Anyone have any comments or suggestions for improving tweaking this unit (aside from you shouldn't have bought it!!) |
#5
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I find the subject of this discussion to be of great interest. I
recently acquired a Rusnok vertical head that will be mounted on a small horizontal mill. The Rusnok head uses Y collets which are double angle collets. While I would much rather use an end mill holder for the reasons stated in earlier posts, I seriously doubt that I will find any end mill holder that will fit this Rusnok head. If anyone knows differently, I would love to hear about it. TMT "Daniel A. Mitchell" wrote in message ... Collets are more convenient, and clamp with less potential 'runout', but do not hold the cutter as securely as an end mill holder. Sooner or later you will likely have a collet slip under the cutting force of the mill. This can (and likely will) cause damage to workpiece and or cutter, and could cause damage to the operator or machine. Unless you confine yourself to making very light cuts, end mill holders are more dependable in the long run. That said, many just use collets with only rare problems. I HAVE had collets slip, but I still use them on occasion (odd cutter shank sizes, etc.), though I prefer end mill holders. Dan Mitchell ========== Bradford Chaucer wrote: I just acquired am benchtop vertical mill that takes R8 colletts. It comes with a drill chuck which I know is not advised for milling. I have seen sets of both R8 colletts and R8 endmill holders. The difference as I see it is that the endmill holder protrudes from the end of the sleeve more than the collett does and it has a set screw for clamping on the flat on an end mill. My question is whether a collett is sufficient for holding endmills or am I advised to opt for the end mill holders?? BTW the mill is the mini-bench top unit sold by Harbor Freight. I made the "Mistake" of dropping in on the store in South Carolina :-) Anyone have any comments or suggestions for improving tweaking this unit (aside from you shouldn't have bought it!!) |
#6
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End mill holders are designed to hold end mills. Collets are workholding
devices. That said, you can use a collet to hold an end mill. The problem is that there's no way to lock the end mill in the collet to prevent it from sucking out while cutting. That could ruin a work piece in which you'd invested a lot of time. You can probably get away with it indefinitely on a small machine taking light cuts, but it is something to consider. Gary Although there are some collets specifically designed to hold end mills. Don't know if they are available in R8 or not, but I have a couple of 40 taper collet chucks for my horizontal mill that take TG100 collets. Most of the collets are plain, but some are "No Pull" styles which have a plug that locks into the flat on a Weldon shank. Can't use them on a regular shank, though, unless you remove the plug. John Martin |
#7
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Gary R Coffman wrote:
On Wed, 06 Aug 2003 22:54:44 GMT, Bradford Chaucer wrote: My question is whether a collett is sufficient for holding endmills or am I advised to opt for the end mill holders?? End mill holders are designed to hold end mills. Collets are workholding devices. That said, you can use a collet to hold an end mill. The problem is that there's no way to lock the end mill in the collet to prevent it from sucking out while cutting. That could ruin a work piece in which you'd invested a lot of time. You can probably get away with it indefinitely on a small machine taking light cuts, but it is something to consider. Gary Are double angle collets any better? I'm getting a set of DA400 that I plan on using with my Nichols Miller so I don't have to disassemble the drawbar to change endmill sizes. |
#8
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Once a cutter is clamped in an end mill holder, the holder may be
removed and then later reinstalled with the cutter remaining in (closely) the same position. Not precise (depends on how tight you pull the drawbar), but good enough for may purposes. certainly far more reproducible than collets. With collets, the cutter is just randomly (with the usual collets like R8) located. Without some kind of 'collet stop' the cutter can locate (longitudinally) most anywhere. Worse, as you tighten a collet the cutter position changes substantially as the collet 'draws in' (FAR more than with an end mill holder). You can't get the cutter back in the same position without using an indicator or gage block of some kind. Once you get it tight and find it's in the wrong position, you can't adjust it dependably without loosening it, which changes it's position unpredictably. Of course, you can adjust the spindle or mill head, but that's not what's being discussed. Double angle collets have the same problem as above, unless both tapers are the SAME angle (NOT the usual case). Such collets may be more suitable to having a 'collet stop' of some kind fitted. And as others have pointed out, there ARE special collets that both locate and hold end mills properly, but again that's not what's being discussed. Dan Mitchell ========== ATP wrote: Gary R Coffman wrote: On Wed, 06 Aug 2003 22:54:44 GMT, Bradford Chaucer wrote: My question is whether a collett is sufficient for holding endmills or am I advised to opt for the end mill holders?? End mill holders are designed to hold end mills. Collets are workholding devices. That said, you can use a collet to hold an end mill. The problem is that there's no way to lock the end mill in the collet to prevent it from sucking out while cutting. That could ruin a work piece in which you'd invested a lot of time. You can probably get away with it indefinitely on a small machine taking light cuts, but it is something to consider. Gary Are double angle collets any better? I'm getting a set of DA400 that I plan on using with my Nichols Miller so I don't have to disassemble the drawbar to change endmill sizes. |
#9
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On Fri, 08 Aug 2003 10:48:28 GMT, "ATP"
wrote: Are double angle collets any better? I'm getting a set of DA400 that I plan on using with my Nichols Miller so I don't have to disassemble the drawbar to change endmill sizes. In theory, the double angle collets are not pulled towards the spindle as they tighten so the cutter extension or offset does not change. Also the collets in many of the double angle collets (like the ER series) have a much larger gripping range. Those typically have a 1 mm or .040" range while collets like R8 and 5C only have a few thousandths. -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 80,000 Newsgroups - 16 Different Servers! =----- |
#10
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In article ,
Jack Erbes wrote: On Fri, 08 Aug 2003 10:48:28 GMT, "ATP" wrote: Are double angle collets any better? I'm getting a set of DA400 that I plan on using with my Nichols Miller so I don't have to disassemble the drawbar to change endmill sizes. In theory, the double angle collets are not pulled towards the spindle as they tighten so the cutter extension or offset does not change. Hmm ... I could see this with a single-angle, with a shoulder at the back, and the nosepiece closing it at the front only. (I guess that you could consider this double-angle, with the rear angle being 90 degrees. :-) With a double-angle, with identical angles at front and back, I would expect the collet to move in half the distance of the nosepiece travel (once compression starts). In other words -- reduced travel, but not zero. For ones like the ER, which have a shallow angle at the back, and a steep angle at the nose, I would expect the collet to move in excess of that half of nosepiece travel. I think that the shallower the rear angle, the better the possible concentricity. Also the collets in many of the double angle collets (like the ER series) have a much larger gripping range. Those typically have a 1 mm or .040" range while collets like R8 and 5C only have a few thousandths. Agreed -- "ER" stands for "Extended Range" after all. I've got a set of those for my Compact-5/CNC (which also fit the C5 milling head, although that is actually mounted on a separate X-Y base, instead of to the back of the lathe bed as was originally intended when it was designed. :-) I can certainly testify to the pull-in in the ER series of collets used as either workholding or toolholding collets. Enjoy, 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 --- |
#11
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In article , Len S wrote:
Some have said that on *really* heavy work and end mill can be "sucked" out of a collet - a small amount, but enought to ruin a precise job. I have not seen this, but also don't anything super heavy. It doesn't need to be heavy. It's happened to me twice, and not too long ago it happened to the foreman at work. He immediately bought a set of endmill holders. -- =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- Mike Graham | Metalworker, rustic, part-time zealot. | http://www.metalmangler.com| Caledon, Ontario, Canada |
#12
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not too long
ago it happened to the foreman at work. He immediately bought a set of endmill holders. me too.......... Paul in AJ AZ |
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