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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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Big hole, little press
Howdy,
I am building a half-rack squat rack for weightlifting. For a conceptual reference, here is a picture of one particular commercially available unit: http://i42.tinypic.com/2e3rcdc.jpg For my version, I am using 3"x3" square steel tubing with an 11 gauge (~1/8") wall thickness. The vertical members will be drilled through in a couple dozen locations (for mounting the bar holders and safeties to), each to a diameter of one inch. And therein lies my issue. My drill press is a small bench mount Delta, with a 1/4hp motor, two inch plunge depth, and a 1/2 inch chuck. My first thought is to use a Silver and Demming (reduced shank) drill bit, 1/2" shank, 1" drill. The plan is to set it up outside, build a sturdy dowelled jig for locating purposes, and use water as coolant. I will drill through one side, then flip it over to drill the other side. I come to you here today for a reality check. While I realize that this it will take awhile, this being a one-off project means I am okay with it taking several days to complete the drilling cycle. My main concern, then, is this: am I out of my tree to consider drilling one inch holes in 1/8" material with a 1/4 horsepower drill press? Thank you for any and all perspectives you would be so kind as to convey to me, Jon |
#2
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Big hole, little press
"Jon Danniken" wrote in message ... Howdy, snip. My main concern, then, is this: am I out of my tree to consider drilling one inch holes in 1/8" material with a 1/4 horsepower drill press? You'd have more than one problem. Even with decent fixturing, it's entirely possible that your drilled holes, assuming you had success, would not line up. Part of the problem would be the condition of the material, which most likely is not uniform in size, nor square. The big problem you'd have isn't just power. Small drill presses are expected to turn small drills, so they are geared accordingly. In order to run a 1" drill without damage, it would have to be turned down around 475 RPM. If you can't run that slowly, you're likely to damage the drill from heating. One more thing to consider. Drilling large holes in thin material generally results in three sided holes (holes that will not accept a pin the same size as the drill used to drill the hole). I expect you won't enjoy much success with your plan. A mill would really help. Alternately, if you can run slow enough and can step drill, you could use a reamer to size the holes. Overall, you would be best served if you could drill through both sides at the same time. Harold |
#3
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Big hole, little press
DON"T do it that way - you will be VERY unhappy - get yourself a decent
bimetal hole saw of the proper diameter and use that - it will take less power, it will make round holes, and you will not kill yourself - use some cutting fluid "Jon Danniken" wrote in message ... Howdy, I am building a half-rack squat rack for weightlifting. For a conceptual reference, here is a picture of one particular commercially available unit: http://i42.tinypic.com/2e3rcdc.jpg For my version, I am using 3"x3" square steel tubing with an 11 gauge (~1/8") wall thickness. The vertical members will be drilled through in a couple dozen locations (for mounting the bar holders and safeties to), each to a diameter of one inch. And therein lies my issue. My drill press is a small bench mount Delta, with a 1/4hp motor, two inch plunge depth, and a 1/2 inch chuck. My first thought is to use a Silver and Demming (reduced shank) drill bit, 1/2" shank, 1" drill. The plan is to set it up outside, build a sturdy dowelled jig for locating purposes, and use water as coolant. I will drill through one side, then flip it over to drill the other side. I come to you here today for a reality check. While I realize that this it will take awhile, this being a one-off project means I am okay with it taking several days to complete the drilling cycle. My main concern, then, is this: am I out of my tree to consider drilling one inch holes in 1/8" material with a 1/4 horsepower drill press? Thank you for any and all perspectives you would be so kind as to convey to me, Jon |
#4
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Big hole, little press
Bill Noble wrote:
DON"T do it that way - you will be VERY unhappy - get yourself a decent bimetal hole saw of the proper diameter and use that - it will take less power, it will make round holes, and you will not kill yourself - use some cutting fluid Ah, thanks Bill, I hadn't considered using a bimetal hole saw. Do you think my 1/4 horsepower drill press has enough horse to turn a one inch bimetal hole saw through 1/8" mild steel? Thanks again, Jon |
#5
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Big hole, little press
Harold & Susan Vordos wrote:
You'd have more than one problem. Even with decent fixturing, it's entirely possible that your drilled holes, assuming you had success, would not line up. Part of the problem would be the condition of the material, which most likely is not uniform in size, nor square. Thanks, Harold. Fortunately one of the benefits of a half-rack is that there is less of a need for precision - there are no back tube holes to match to the front tube holes as in a four-corner rack. The holes themselves on my rack receive a one inch diameter steel peg, and are only used to prevent vertical motion of the barbell hook once it is attached to the upright. To prevent movement in the horizontal direction, the barbell hook uses a wrap-around metal strap. You might be able to get an idea of this with this image, on the off chance that you haven't come across such an animal in the past: http://i41.tinypic.com/2mgw787.jpg The big problem you'd have isn't just power. Small drill presses are expected to turn small drills, so they are geared accordingly. In order to run a 1" drill without damage, it would have to be turned down around 475 RPM. If you can't run that slowly, you're likely to damage the drill from heating. Thanks Harold, I hadn't calculated the feed rate yet, and I appreciate you doing that for me. My drill press only goes down to 620 RPM. As for damaging by heating, wouldn't the cutting fluid (in this case water) keep the bit from burning out if it were run at 620 RPM? (I am not experienced enough to know this). One more thing to consider. Drilling large holes in thin material generally results in three sided holes (holes that will not accept a pin the same size as the drill used to drill the hole). I expect you won't enjoy much success with your plan. A mill would really help. Aye, I may likely have to ream the holes out, depending upon the diameter of the one-inch steel pegs to be inserted into them; thanks. Alternately, if you can run slow enough and can step drill, you could use a reamer to size the holes. Overall, you would be best served if you could drill through both sides at the same time. Indeed, that would save half of the work. One solution I am considering is to incorporate my jig with a dowel inline with the spindle, underneath the tube which has already had one side drilled. Using this method, the tube would lock into place on the dowel, locating the upright drill with an accuracy based on how well I can set up the jig in relation to the spindle. Thanks again Harold, Jon |
#6
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Big hole, little press
On Fri, 23 Apr 2010 21:58:43 -0700, "Jon Danniken"
wrote: Howdy, I am building a half-rack squat rack for weightlifting. For a conceptual reference, here is a picture of one particular commercially available unit: http://i42.tinypic.com/2e3rcdc.jpg For my version, I am using 3"x3" square steel tubing with an 11 gauge (~1/8") wall thickness. The vertical members will be drilled through in a couple dozen locations (for mounting the bar holders and safeties to), each to a diameter of one inch. And therein lies my issue. My drill press is a small bench mount Delta, with a 1/4hp motor, two inch plunge depth, and a 1/2 inch chuck. My first thought is to use a Silver and Demming (reduced shank) drill bit, 1/2" shank, 1" drill. The plan is to set it up outside, build a sturdy dowelled jig for locating purposes, and use water as coolant. I will drill through one side, then flip it over to drill the other side. I come to you here today for a reality check. While I realize that this it will take awhile, this being a one-off project means I am okay with it taking several days to complete the drilling cycle. My main concern, then, is this: am I out of my tree to consider drilling one inch holes in 1/8" material with a 1/4 horsepower drill press? Thank you for any and all perspectives you would be so kind as to convey to me, Jon Frankly Jon..you would be better served if you made up templates to mark your holes, center punch them..and then use a 1/2" drill motor. While you could perhaps(not likely) drill them with a 1/4hp drill press..you will have to work very slowly, and probably increasingly bigger holes first. A 1" drill isnt magic..but it takes some OOMPH to actually drill with one. You can make templates out of file folder cardboard every easily. And Id at least use a 3/16" drill for a pilot drill. The other option..would be to use a UniBit, with a 1/2" drill. You might even get by with a 3/8" DECENT drill motor...but...cringe....I personally would rather not. Gunner "First Law of Leftist Debate The more you present a leftist with factual evidence that is counter to his preconceived world view and the more difficult it becomes for him to refute it without losing face the chance of him calling you a racist, bigot, homophobe approaches infinity. This is despite the thread you are in having not mentioned race or sexual preference in any way that is relevant to the subject." Grey Ghost |
#7
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Big hole, little press
On Sat, 24 Apr 2010 00:23:28 -0700, "Jon Danniken"
wrote: Bill Noble wrote: DON"T do it that way - you will be VERY unhappy - get yourself a decent bimetal hole saw of the proper diameter and use that - it will take less power, it will make round holes, and you will not kill yourself - use some cutting fluid Ah, thanks Bill, I hadn't considered using a bimetal hole saw. Do you think my 1/4 horsepower drill press has enough horse to turn a one inch bimetal hole saw through 1/8" mild steel? Thanks again, Jon Thats not a bad suggestion at all.. And you MIGHT have enough power. Maybe. Could be. Dont have a hand drill?? Gunner "First Law of Leftist Debate The more you present a leftist with factual evidence that is counter to his preconceived world view and the more difficult it becomes for him to refute it without losing face the chance of him calling you a racist, bigot, homophobe approaches infinity. This is despite the thread you are in having not mentioned race or sexual preference in any way that is relevant to the subject." Grey Ghost |
#8
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Big hole, little press
On Sat, 24 Apr 2010 00:23:28 -0700, "Jon Danniken"
wrote: Bill Noble wrote: DON"T do it that way - you will be VERY unhappy - get yourself a decent bimetal hole saw of the proper diameter and use that - it will take less power, it will make round holes, and you will not kill yourself - use some cutting fluid Ah, thanks Bill, I hadn't considered using a bimetal hole saw. Do you think my 1/4 horsepower drill press has enough horse to turn a one inch bimetal hole saw through 1/8" mild steel? Thanks again, Jon I've got a drill press, probably the same size as you, although I built second set of belt sheaves to reduce the speed but I have cut 2 inch holes in aluminum plate with no problems. Takes a while but gets it done. The secret is a sharp hole saw and light feed pressure. and a lot of oil :-) John B. Slocomb (johnbslocombatgmaildotcom) |
#9
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Big hole, little press
On Sat, 24 Apr 2010 00:23:28 -0700, the infamous "Jon Danniken"
scrawled the following: Bill Noble wrote: DON"T do it that way - you will be VERY unhappy - get yourself a decent bimetal hole saw of the proper diameter and use that - it will take less power, it will make round holes, and you will not kill yourself - use some cutting fluid Ah, thanks Bill, I hadn't considered using a bimetal hole saw. Do you think my 1/4 horsepower drill press has enough horse to turn a one inch bimetal hole saw through 1/8" mild steel? With prayer, patience, and plenty of cutting oil, yes. -- ....in order that a man may be happy, it is necessary that he should not only be capable of his work, but a good judge of his work. -- John Ruskin |
#10
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Big hole, little press
Gunner Asch wrote:
Frankly Jon..you would be better served if you made up templates to mark your holes, center punch them..and then use a 1/2" drill motor. Heya Gunner, good to see ya, mate! Hope everything is well in Gunnerville. Thanks for the suggestion, but I just don't have the precision with a hand motor to get anywhere near straight. I have seen the little holders for hand motors, but I don't know how precise I could be with one of those. While you could perhaps(not likely) drill them with a 1/4hp drill press..you will have to work very slowly, and probably increasingly bigger holes first. Okay, now that brings up a question I have. If you had an adequately rated drill press, and needed to drill a number of one inch diameter holes in 1/8" mild steel, would you use a hole saw or a twist bit? What would you consider to be the minimum horsepower for either type of bit? Also, would you consider a S/D bit suitable for a one inch hole if your chuck was only 1/2"? Thanks Gunner, Jon |
#11
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Big hole, little press
On Fri, 23 Apr 2010 21:58:43 -0700, "Jon Danniken"
wrote: Howdy, I am building a half-rack squat rack for weightlifting. For a conceptual reference, here is a picture of one particular commercially available unit: http://i42.tinypic.com/2e3rcdc.jpg For my version, I am using 3"x3" square steel tubing with an 11 gauge (~1/8") wall thickness. The vertical members will be drilled through in a couple dozen locations (for mounting the bar holders and safeties to), each to a diameter of one inch. Unless you're using existing fittings that require the 1" holes, I'd reduce their diameter. As a point of reference, I recently had to look at #80 roller chain for lifting service. The chain pins are 5/16" diameter; its minimum tensile strength is 12,500 lbs. The pins are in double shear (two shear planes) and made of alloy steel, but you get the picture. If you're stuck with 1" holes, I second the hole saw. -- Ned Simmons |
#12
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Big hole, little press
Ned Simmons wrote:
Unless you're using existing fittings that require the 1" holes, I'd reduce their diameter. As a point of reference, I recently had to look at #80 roller chain for lifting service. The chain pins are 5/16" diameter; its minimum tensile strength is 12,500 lbs. The pins are in double shear (two shear planes) and made of alloy steel, but you get the picture. If you're stuck with 1" holes, I second the hole saw. Hi Ned, and thank you for your reply. I actually noticed the same thing the other day when I looked at the pin on my ball mount (it's a 5/8" pin in a 2"x2" piece of square tubing). The difference, however, is that the ball mount tubing is 3/32" thickness, instead of the 1/8" thickness of the 3x3 I will be working with. While I would likely agree with you that it would be sturdy enough for my intended usage, I will still be using one-inch holes in 3x3 tubing, for no other reason than to give myself a little extra cushion for the pushin (and to help compensate for my lack of perfect weldments, et cetera). Also, thanks for the suggestion about the hole saw. Jon |
#13
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Big hole, little press
On Sat, 24 Apr 2010 06:51:38 -0700, "Jon Danniken"
wrote: Gunner Asch wrote: Frankly Jon..you would be better served if you made up templates to mark your holes, center punch them..and then use a 1/2" drill motor. Heya Gunner, good to see ya, mate! Hope everything is well in Gunnerville. Thanks for the suggestion, but I just don't have the precision with a hand motor to get anywhere near straight. I have seen the little holders for hand motors, but I don't know how precise I could be with one of those. While you could perhaps(not likely) drill them with a 1/4hp drill press..you will have to work very slowly, and probably increasingly bigger holes first. Okay, now that brings up a question I have. If you had an adequately rated drill press, and needed to drill a number of one inch diameter holes in 1/8" mild steel, would you use a hole saw or a twist bit? What would you consider to be the minimum horsepower for either type of bit? Also, would you consider a S/D bit suitable for a one inch hole if your chuck was only 1/2"? Thanks Gunner, Jon A hole saw with plenty of cutting fluid will be the lowest-torque approach. Next would be a step bit, last choice would be a 1" dia twist drill. The twist drill would be better for production rate in heavier material with suitable machinery driving it, but hole saws and step drills (unibit) work much better when the dia of the hole is considerably larger than the thickness of the material. 1/4 hp at 620 RPM is 25.4 in-lbf of torque. That might drive a good holesaw if nothing binds up due to deflection. It would help a lot if you could change pulleys to get the speed down. That would increase your torque and decrease heating. At 620 RPM a 1" hole saw will have a tooth speed of 162 SFPM, which is on the high side of the range for bimetal cutting mild steel but not absurdly out of the ball park. The range generally goes from 80 to 200 SFPM. Use lots of juice. Slower would be better. |
#14
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Big hole, little press
On Sat, 24 Apr 2010 06:51:38 -0700, "Jon Danniken"
wrote: Gunner Asch wrote: Frankly Jon..you would be better served if you made up templates to mark your holes, center punch them..and then use a 1/2" drill motor. Heya Gunner, good to see ya, mate! Hope everything is well in Gunnerville. Thanks for the suggestion, but I just don't have the precision with a hand motor to get anywhere near straight. I have seen the little holders for hand motors, but I don't know how precise I could be with one of those. While you could perhaps(not likely) drill them with a 1/4hp drill press..you will have to work very slowly, and probably increasingly bigger holes first. Okay, now that brings up a question I have. If you had an adequately rated drill press, and needed to drill a number of one inch diameter holes in 1/8" mild steel, would you use a hole saw or a twist bit? What would you consider to be the minimum horsepower for either type of bit? Also, would you consider a S/D bit suitable for a one inch hole if your chuck was only 1/2"? Thanks Gunner, Jon Id consider a 1/3hp drill press to be the minimum with a drill bit and perhaps a 1/4 hp a minimum with a hole saw. If as everyone suggested, you gear it down and use lots of oil G How many holes do you actually need to drill? Up to say..15 or so..if you took your time and used oil and didnt try to force em....Id say you would be ok with a 1" hole saw. A good quality one like a Lenox. The other option is to use a unibit/step drill of some sort..and take your time. 1/4 hp..really isnt very much for a largish cutter of any sort. Shrug Gunner "First Law of Leftist Debate The more you present a leftist with factual evidence that is counter to his preconceived world view and the more difficult it becomes for him to refute it without losing face the chance of him calling you a racist, bigot, homophobe approaches infinity. This is despite the thread you are in having not mentioned race or sexual preference in any way that is relevant to the subject." Grey Ghost |
#15
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Big hole, little press
How many holes do you actually need to drill? Up to say..15 or so..if
you took your time and used oil and didnt try to force em....Id say you would be ok with a 1" hole saw. A good quality one like a Lenox. The other option is to use a unibit/step drill of some sort..and take your time. 1/4 hp..really isnt very much for a largish cutter of any sort. One thing I've not seen mentioned. Holes saws tend to give you quite a bit overisze hole with 25 thou over not uncommon. The uni bit will give you very close to 1.00 Karl |
#16
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Big hole, little press
Don Foreman wrote:
A hole saw with plenty of cutting fluid will be the lowest-torque approach. Next would be a step bit, last choice would be a 1" dia twist drill. The twist drill would be better for production rate in heavier material with suitable machinery driving it, but hole saws and step drills (unibit) work much better when the dia of the hole is considerably larger than the thickness of the material. 1/4 hp at 620 RPM is 25.4 in-lbf of torque. That might drive a good holesaw if nothing binds up due to deflection. It would help a lot if you could change pulleys to get the speed down. That would increase your torque and decrease heating. At 620 RPM a 1" hole saw will have a tooth speed of 162 SFPM, which is on the high side of the range for bimetal cutting mild steel but not absurdly out of the ball park. The range generally goes from 80 to 200 SFPM. Use lots of juice. Slower would be better. Thanks Don, I appreciate it. Right now 620RPM is the slowest speed the drillpress will go down to, with 3 7/8" OD pulley on the quill and 1 1/2" OD pulley on the motor shaft. BUT: I dug around in the shop and found my old compressor, with the 1hp motor (not compressor duty) motor still attached to it. If I can make an adaptor plate between the 1hp motor and the drill press mount, it *will* fit. The only rub is that it has a 5/8" shaft (3/16" keyway), and the smallest single pulley with those dimensions from McmasterCarr has an OD of 1 3/4". I'm guessing that extra 1/4" inch will multiply the RPM by 1.75/1.5 (if that is the correct formula), and I will end up with about 725RPM at 1hp. That's a fair bit faster, but with the extra torque perhaps I could then use the 1" silver/demming drill bit with coolant and crank it hard through the workpiece. Hmmm.... Jon |
#17
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Big hole, little press
Gunner Asch wrote:
Id consider a 1/3hp drill press to be the minimum with a drill bit and perhaps a 1/4 hp a minimum with a hole saw. If as everyone suggested, you gear it down and use lots of oil G How many holes do you actually need to drill? Up to say..15 or so..if you took your time and used oil and didnt try to force em....Id say you would be ok with a 1" hole saw. A good quality one like a Lenox. The other option is to use a unibit/step drill of some sort..and take your time. 1/4 hp..really isnt very much for a largish cutter of any sort. Thanks again, Gunner, I appreciate it. The number of holes will depend upon how closely I can space the holes without weakening the uprights (which are 3x3 square tube @ 1/8" wall thickness). If I go with 2" vertical spacing, I'm looking at about 80 holes; with 3" spacing I'm looking at about 54 holes (this assumes holes from 28" high to 68" high, which may increase slightly if I discover I need holes up higher). That'd mean going through a lot of hole cutters! (copied from the reply I just sent to Don BUT: I dug around in the shop and found my old compressor, with the 1hp motor (not compressor duty) motor still attached to it. If I make an adaptor plate between the 1hp motor and the drill press mount, it *will* fit. The only rub is that it has a 5/8" shaft (3/16" keyway), and the smallest single pulley with those dimensions from McmasterCarr has an OD of 1 3/4". I'm guessing that extra 1/4" inch will multiply the RPM by 1.75/1.5 (if that is the correct formula), and I will end up with about 725RPM at 1hp. That's a fair bit faster, but with the extra torque perhaps I could then use the 1" silver/demming drill bit with coolant and crank it hard and fast through the workpiece (unless I can get a smaller single pulley for a 5/8" motor shaft with a 3/16" keyway). Hmmm.... Jon |
#18
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Big hole, little press
Jon Danniken wrote:
Step drill like a Unibit. Easy to power because your only cutting a small amount each time. -- Steve W. (\___/) (='.'=) (")_(") |
#19
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Big hole, little press
On 2010-04-24, JR North wrote:
Forget the S/D drills and hole saw ideas. You need this: http://www.harborfreight.com/cpi/cta...emnumber=96275 Might even get to 1" if you drill slow. Perhaps -- though I'm not sure whether these are made from a real HSS (as claimed) or one of the Chinese alloys which are not as good. TiN is good for wear on a good strong steel, but on a poorer quality steel is just gilding. I would be more likely to trust the ones by Klien which I posted some pointers to in a previous (but recent) response to this thread. Yes, it costs significantly more for the one bit which I suggested, but that one bit is likely to last through all of the (80+) holes you need to drill, while these may not. Still -- use the high sulfur pipe threading oil as coolant/lubricant. Paint it on the cutter before each cut since you don't have flood coolant. 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 --- |
#20
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Big hole, little press
DoN. Nichols wrote:
Maybe -- maybe not. What is the nameplate RPM for that motor vs the one currently in the drill press? If it is a 4-pole motor (a bit below 1800 RPM) and the original was a 2-pole motor (a bit below 3600 RPM) you would gain slower operation as well. (Same for other possible ratios of pole counts on the motors. Hi Don, thanks for your response; they are both 1725s. You're forgetting the tri-lobed holes from a standard drill bit in thin metal which was mentioned earlier. If I go with a twist bit, I will finish it up with a reamer, a tool which I have always been eager to play with. But if you insist on running one -- check whether the shank has three partial flats on it. Without those, the bit is likely to bind and the shank slip in the chuck. Oh man tell me about it! This Delta of mine spins a 3/8" shiny finish when it catches at the end of a hole, and drives me NUTS! Unfortunate, too, because there is a S/D bit in my size for under $10 from Amazon (the flatted one is a Milwaukee at fifty bucks and it got a bad review). I might just try a round shank, and see if I can pound the key enough to lock it in place. You've already had one suggestion to use a Unibit, and I second that. In case you don't know what they are -- they are a stepped drill bit with a single flute which is self-guiding in the metal. They come in various size ranges and step height. How thick is your steel? The steel is 11 gauge (0.12). I do know what a step-drill is, and actually have one of the DrillMaster units from HF. I have always considered it to be a bit for drilling out thin sheet metal; I originally purchased it for making knob holes in a chassis. That I have had more than a couple of suggestions to use one has garenerd my attention, although I must admit a bit of skepticism as to whether or not it is the right tool considering the number of holes (60 to 80) and the thickness of material which I am looking to bore (1/8"). In any case -- instead of using water, I would suggest Rigid high-sulfur thread cutting oil. You won't have to remove as much metal at a pass as you would with the Silver & Demming bit, so there is a greater chance that your drill press will have sufficient torque -- with the above-mentioned cutting oil refreshed for each hole. (Paint it on the unibit with an acid brush or something similar. Thanks for the suggestion, Don. I must admit that I really like water because it is cheap and is easy to flow at a volume sufficient to cool the bit and workpiece. I have used it before with good results in cooling, but perhaps it is the lubrication ability of the bona fide product which makes it shine. Yes -- using the dowel pin to locate the already-drilled hole on the other side makes sense. Thanks, it seemed to be the logical solution. I appreciate the input. Jon |
#21
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Big hole, little press
Note: apologies if this is a dupe; eternal september is living up to it's
name.... DoN. Nichols wrote: Maybe -- maybe not. What is the nameplate RPM for that motor vs the one currently in the drill press? If it is a 4-pole motor (a bit below 1800 RPM) and the original was a 2-pole motor (a bit below 3600 RPM) you would gain slower operation as well. (Same for other possible ratios of pole counts on the motors. Hi Don, thanks for your response; they are both 1725s. You're forgetting the tri-lobed holes from a standard drill bit in thin metal which was mentioned earlier. If I go with a twist bit, I will finish it up with a reamer, a tool which I have always been eager to play with. But if you insist on running one -- check whether the shank has three partial flats on it. Without those, the bit is likely to bind and the shank slip in the chuck. Oh man tell me about it! This Delta of mine spins a 3/8" shiny finish when it catches at the end of a hole, and drives me NUTS! Unfortunate, too, because there is a S/D bit in my size for under $10 from Amazon (the flatted one is a Milwaukee at fifty bucks and it got a bad review). I might just try a round shank, and see if I can pound the key enough to lock it in place. You've already had one suggestion to use a Unibit, and I second that. In case you don't know what they are -- they are a stepped drill bit with a single flute which is self-guiding in the metal. They come in various size ranges and step height. How thick is your steel? The steel is 11 gauge (0.12). I do know what a step-drill is, and actually have one of the DrillMaster units from HF. I have always considered it to be a bit for drilling out thin sheet metal; I originally purchased it for making knob holes in a chassis. That I have had more than a couple of suggestions to use one has garenerd my attention, although I must admit a bit of skepticism as to whether or not it is the right tool considering the number of holes (60 to 80) and the thickness of material which I am looking to bore (1/8"). In any case -- instead of using water, I would suggest Rigid high-sulfur thread cutting oil. You won't have to remove as much metal at a pass as you would with the Silver & Demming bit, so there is a greater chance that your drill press will have sufficient torque -- with the above-mentioned cutting oil refreshed for each hole. (Paint it on the unibit with an acid brush or something similar. Thanks for the suggestion, Don. I must admit that I really like water because it is cheap and is easy to flow at a volume sufficient to cool the bit and workpiece. I have used it before with good results in cooling, but perhaps it is the lubrication ability of the bona fide product which makes it shine. Yes -- using the dowel pin to locate the already-drilled hole on the other side makes sense. Thanks, it seemed to be the logical solution. I appreciate the input. Jon |
#22
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Big hole, little press
Note: apologies if this is a dupe; eternal september is living up to it's
name.... DoN. Nichols wrote: Maybe -- maybe not. What is the nameplate RPM for that motor vs the one currently in the drill press? If it is a 4-pole motor (a bit below 1800 RPM) and the original was a 2-pole motor (a bit below 3600 RPM) you would gain slower operation as well. (Same for other possible ratios of pole counts on the motors. Hi Don, thanks for your response; they are both 1725s. You're forgetting the tri-lobed holes from a standard drill bit in thin metal which was mentioned earlier. If I go with a twist bit, I will finish it up with a reamer, a tool which I have always been eager to play with. But if you insist on running one -- check whether the shank has three partial flats on it. Without those, the bit is likely to bind and the shank slip in the chuck. Oh man tell me about it! This Delta of mine spins a 3/8" shiny finish when it catches at the end of a hole, and drives me NUTS! Unfortunate, too, because there is a S/D bit in my size for under $10 from Amazon (the flatted one is a Milwaukee at fifty bucks and it got a bad review). I might just try a round shank, and see if I can pound the key enough to lock it in place. You've already had one suggestion to use a Unibit, and I second that. In case you don't know what they are -- they are a stepped drill bit with a single flute which is self-guiding in the metal. They come in various size ranges and step height. How thick is your steel? The steel is 11 gauge (0.12). I do know what a step-drill is, and actually have one of the DrillMaster units from HF. I have always considered it to be a bit for drilling out thin sheet metal; I originally purchased it for making knob holes in a chassis. That I have had more than a couple of suggestions to use one has garenerd my attention, although I must admit a bit of skepticism as to whether or not it is the right tool considering the number of holes (60 to 80) and the thickness of material which I am looking to bore (1/8"). In any case -- instead of using water, I would suggest Rigid high-sulfur thread cutting oil. You won't have to remove as much metal at a pass as you would with the Silver & Demming bit, so there is a greater chance that your drill press will have sufficient torque -- with the above-mentioned cutting oil refreshed for each hole. (Paint it on the unibit with an acid brush or something similar. Thanks for the suggestion, Don. I must admit that I really like water because it is cheap and is easy to flow at a volume sufficient to cool the bit and workpiece. I have used it before with good results in cooling, but perhaps it is the lubrication ability of the bona fide product which makes it shine. Yes -- using the dowel pin to locate the already-drilled hole on the other side makes sense. Thanks, it seemed to be the logical solution. I appreciate the input. Jon |
#23
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Big hole, little press
On Sat, 24 Apr 2010 13:16:58 -0700, "Jon Danniken"
wrote: Don Foreman wrote: A hole saw with plenty of cutting fluid will be the lowest-torque approach. Next would be a step bit, last choice would be a 1" dia twist drill. The twist drill would be better for production rate in heavier material with suitable machinery driving it, but hole saws and step drills (unibit) work much better when the dia of the hole is considerably larger than the thickness of the material. 1/4 hp at 620 RPM is 25.4 in-lbf of torque. That might drive a good holesaw if nothing binds up due to deflection. It would help a lot if you could change pulleys to get the speed down. That would increase your torque and decrease heating. At 620 RPM a 1" hole saw will have a tooth speed of 162 SFPM, which is on the high side of the range for bimetal cutting mild steel but not absurdly out of the ball park. The range generally goes from 80 to 200 SFPM. Use lots of juice. Slower would be better. Thanks Don, I appreciate it. Right now 620RPM is the slowest speed the drillpress will go down to, with 3 7/8" OD pulley on the quill and 1 1/2" OD pulley on the motor shaft. BUT: I dug around in the shop and found my old compressor, with the 1hp motor (not compressor duty) motor still attached to it. If I can make an adaptor plate between the 1hp motor and the drill press mount, it *will* fit. The only rub is that it has a 5/8" shaft (3/16" keyway), and the smallest single pulley with those dimensions from McmasterCarr has an OD of 1 3/4". I'm guessing that extra 1/4" inch will multiply the RPM by 1.75/1.5 (if that is the correct formula), and I will end up with about 725RPM at 1hp. That's a fair bit faster, but with the extra torque perhaps I could then use the 1" silver/demming drill bit with coolant and crank it hard through the workpiece. Hmmm.... Please re-read guidance several have offered, then do as you will. A 1" drill bit, silver demming or otherwise, is not a good choice for 11 gage steel, and it's a particularly bad choice in a lightweight drillpress. I have a Bridgeport mill and I have a 1" silver-deming drillbit with 1/2" shank. If I were drilling 11 gage, I'd use a holesaw or a step drill whether in a drillpress or in the mill. Harbor Freight offers a pair of stepdrills for $14.99. http://www.harborfreight.com/cpi/cta...emnumber=96275 These work quite well in a hand-held drillmotor. Drill 1/2" pilot holes on your DP, then enlarge them to suit with a step drill in a handheld that has the low-speed high-torque to get it done. |
#24
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Big hole, little press
In article ,
"Jon Danniken" wrote: Note: apologies if this is a dupe; eternal september is living up to it's name.... DoN. Nichols wrote: [snip] If I go with a twist bit, I will finish it up with a reamer, a tool which I have always been eager to play with. But if you insist on running one -- check whether the shank has three partial flats on it. Without those, the bit is likely to bind and the shank slip in the chuck. Oh man tell me about it! This Delta of mine spins a 3/8" shiny finish when it catches at the end of a hole, and drives me NUTS! I have a Delta DP-350, and the chuck it came with is useless. I had to replace the chuck with a Jacobs. I've heard that Rohm chucks are good too. Unfortunate, too, because there is a S/D bit in my size for under $10 from Amazon (the flatted one is a Milwaukee at fifty bucks and it got a bad review). I might just try a round shank, and see if I can pound the key enough to lock it in place. Tighten using all three key holes one after another. But it will still likely spin free. I never could get the OEM chuck to grip firmly enough. You've already had one suggestion to use a Unibit, and I second that. In case you don't know what they are -- they are a stepped drill bit with a single flute which is self-guiding in the metal. They come in various size ranges and step height. How thick is your steel? The steel is 11 gauge (0.12). I do know what a step-drill is, and actually have one of the DrillMaster units from HF. I have always considered it to be a bit for drilling out thin sheet metal; I originally purchased it for making knob holes in a chassis. That I have had more than a couple of suggestions to use one has garenerd my attention, although I must admit a bit of skepticism as to whether or not it is the right tool considering the number of holes (60 to 80) and the thickness of material which I am looking to bore (1/8"). I have used Irwin Unibits in thick steel sheet. They work just fine. But you do need lubrication. I typically use black sulfur oil for steel and stainlesss steel, and denatured alcohol for aluminum. Or water-soluble oil for all metals listed. I would not attempt to use a 1" twist drill in such a small machine, even if slipping could be prevented. And in a big enough machine, when the bit caught, it would swing the tubing and smack you, hard. The workpiece must be somehow clamped to the drillpress table. Even with a unibit, the workpiece must be clamped somehow. In any case -- instead of using water, I would suggest Rigid high-sulfur thread cutting oil. You won't have to remove as much metal at a pass as you would with the Silver & Demming bit, so there is a greater chance that your drill press will have sufficient torque -- with the above-mentioned cutting oil refreshed for each hole. (Paint it on the unibit with an acid brush or something similar. Thanks for the suggestion, Don. I must admit that I really like water because it is cheap and is easy to flow at a volume sufficient to cool the bit and workpiece. I have used it before with good results in cooling, but perhaps it is the lubrication ability of the bona fide product which makes it shine. While water is certainly convenient, I would not use water for this. DoN is right. Use black sulfur oil, which is made for exactly this purpose, and is cheap and widely available. Lubrication is the issue, plus chemistry. The sulfur is there for a reason. Cooling is less of an issue with HSS tools. Many hardware stores carry black sulfur cutting oil, as does Home Despot (may be in plumbing, may be in hardware), and all plumbing supply houses. There are many brands. You will also want a small brush for applying the oil. The traditional approach is to use a seamless steel tuna can and an acid brush. Seamless is good because the oil will seep through the seals in some kinds of tin can. Steel is good because the sulfur in the oil will stain non-ferrous alloys. Given the number of large holes to made, I have to ask why you don't just get a larger and stronger drill press. Joe Gwinn |
#25
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Big hole, little press
"Don Foreman" wrote in message ... snip A hole saw with plenty of cutting fluid will be the lowest-torque approach. Next would be a step bit, last choice would be a 1" dia twist drill. The twist drill would be better for production rate in heavier material with suitable machinery driving it, but hole saws and step drills (unibit) work much better when the dia of the hole is considerably larger than the thickness of the material. Exactly. In spite of my suggestion, earlier, to follow the drilled hole with a reamer, I would use a hole saw, assuming I could get one that created a hole in keeping with my needs. They tend to cut a ragged hole until they self pilot. In answer to the concept of water allowing a greater surface speed, while coolant keeps temperature under control, it has little effect of the cutting edge. If you run too fast, the cutting edge overheats and burns, in spite of being cooled. Surface speed must be reduced, or tools that can withstand greater surface speed would be required. Harold |
#26
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Big hole, little press
I'll throw in a vote for using a hole saw. And add that they are good
to have around, even if they are not used that much. As far as using a hole saw, there is something very important to know: the teeth will become clogged with chips VERY quickly - maybe in 1/2 revolution, if you're actually feeding & not just rubbing the teeth G. You can "peck" to clean the teeth, but better is to pre-drill a couple of small clearance holes just inside the circumference of the hole saw. For your 1" holes, I'd drill 2, 1/4" clearance holes 180 degrees apart. Makes a BIG difference. Bob |
#27
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Big hole, little press
My drill press is a small bench mount Delta, with a 1/4hp motor, two inch
plunge depth, and a 1/2 inch chuck. My first thought is to use a Silver and Demming (reduced shank) drill bit, 1/2" shank, 1" drill. Others have addressed the bit, and there has been passing reference to gearing down the drill press. Here's how I did that for mine: http://home.comcast.net/~glyford/js/js.htm This old article did something similar: http://www.projectsplans.com/downloa...rill_press.pdf I also second the recommendation for either a vise or clamps. If not using a vise, a block or piece of angle clamped to the table may help keep your distance in from the edge of the 3x3 consistent, only requiring you to slide it axially for each hole to line up your next mark under the bit--as long as your table doesn't swing around the column on you, such as might happen if the bit jams. --Glenn Lyford |
#28
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Big hole, little press
What's that Lassie? You say that Harold & Susan Vordos fell down the
old rec.crafts.metalworking mine and will die if we don't mount a rescue by Sun, 25 Apr 2010 21:25:46 GMT: I would use a hole saw, assuming I could get one that created a hole in keeping with my needs. They tend to cut a ragged hole until they self pilot. When I use hole saws, I replace the pilot drill with a solid round bar. Helps a lot with thinner stock that the pilot drill wouldn't make a round hole in. -- Dan H. northshore MA. |
#29
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Big hole, little press
Use a step drill for sheet. It outperforms twist drills.
Martin Don Foreman wrote: On Sat, 24 Apr 2010 13:16:58 -0700, "Jon Danniken" wrote: Don Foreman wrote: A hole saw with plenty of cutting fluid will be the lowest-torque approach. Next would be a step bit, last choice would be a 1" dia twist drill. The twist drill would be better for production rate in heavier material with suitable machinery driving it, but hole saws and step drills (unibit) work much better when the dia of the hole is considerably larger than the thickness of the material. 1/4 hp at 620 RPM is 25.4 in-lbf of torque. That might drive a good holesaw if nothing binds up due to deflection. It would help a lot if you could change pulleys to get the speed down. That would increase your torque and decrease heating. At 620 RPM a 1" hole saw will have a tooth speed of 162 SFPM, which is on the high side of the range for bimetal cutting mild steel but not absurdly out of the ball park. The range generally goes from 80 to 200 SFPM. Use lots of juice. Slower would be better. Thanks Don, I appreciate it. Right now 620RPM is the slowest speed the drillpress will go down to, with 3 7/8" OD pulley on the quill and 1 1/2" OD pulley on the motor shaft. BUT: I dug around in the shop and found my old compressor, with the 1hp motor (not compressor duty) motor still attached to it. If I can make an adaptor plate between the 1hp motor and the drill press mount, it *will* fit. The only rub is that it has a 5/8" shaft (3/16" keyway), and the smallest single pulley with those dimensions from McmasterCarr has an OD of 1 3/4". I'm guessing that extra 1/4" inch will multiply the RPM by 1.75/1.5 (if that is the correct formula), and I will end up with about 725RPM at 1hp. That's a fair bit faster, but with the extra torque perhaps I could then use the 1" silver/demming drill bit with coolant and crank it hard through the workpiece. Hmmm.... Please re-read guidance several have offered, then do as you will. A 1" drill bit, silver demming or otherwise, is not a good choice for 11 gage steel, and it's a particularly bad choice in a lightweight drillpress. I have a Bridgeport mill and I have a 1" silver-deming drillbit with 1/2" shank. If I were drilling 11 gage, I'd use a holesaw or a step drill whether in a drillpress or in the mill. Harbor Freight offers a pair of stepdrills for $14.99. http://www.harborfreight.com/cpi/cta...emnumber=96275 These work quite well in a hand-held drillmotor. Drill 1/2" pilot holes on your DP, then enlarge them to suit with a step drill in a handheld that has the low-speed high-torque to get it done. |
#30
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Big hole, little press
On 2010-04-25, Jon Danniken wrote:
DoN. Nichols wrote: Maybe -- maybe not. What is the nameplate RPM for that motor vs the one currently in the drill press? If it is a 4-pole motor (a bit below 1800 RPM) and the original was a 2-pole motor (a bit below 3600 RPM) you would gain slower operation as well. (Same for other possible ratios of pole counts on the motors. Hi Don, thanks for your response; they are both 1725s. So much for that possible benefit. :-) You're forgetting the tri-lobed holes from a standard drill bit in thin metal which was mentioned earlier. If I go with a twist bit, I will finish it up with a reamer, a tool which I have always been eager to play with. Hmm ... what kind of reamer? Single size reamers are really designed to remove very little metal from a slightly undersized hole to produce a precise hole size. I don't think that one would work well in a tri-lobed hole. Or -- if you are talking about a tapered reamer, that (under manual power) might do reasonably well. The one I'm most familiar with goes from perhaps 3/16" to 1/2" with a T-handle. There are larger ones designed to ream the ID of pipes to remove burrs. These are fitted with the square shank which fits a brace (drill holder for wood bits). That, with a brace might work well, as long as you had a way to make sure that you stop before the hole gets too large. But if you insist on running one -- check whether the shank has three partial flats on it. Without those, the bit is likely to bind and the shank slip in the chuck. Oh man tell me about it! This Delta of mine spins a 3/8" shiny finish when it catches at the end of a hole, and drives me NUTS! :-) Do you use the chuck key in all three positions? This makes for a somewhat better grip. Unfortunate, too, because there is a S/D bit in my size for under $10 from Amazon (the flatted one is a Milwaukee at fifty bucks and it got a bad review). Perhaps the bad review is because of the relative price? A quick plunge into MSC's online catalog search for "Cutting Tools"/drills/Reduced shank drills" and limiting to 1/2" shank 1" diameter, and Cobalt steel (gets you better wear life) finds six of them, ranging from $67.70 to $121.07. None of them state whether they have flats on the shank. HSS has 9 bits. Price range from $31.97 to $75.79. Looking at the illustration for MSC #00649616 (Triumph Twist Drill) I see that this one has a split point, which would mean less force needed to drill directly without a pilot hole. The price on this one is $52.26. I might just try a round shank, and see if I can pound the key enough to lock it in place. Try tightening it in all three key positions. That will help a bit -- though probably not enough. If you have a milling machine and a spin indexer, you could machine your own flats on the shank if it turns out to not have them. FWIW -- the flute length on these is 3" -- but if your drill press's stroke is shorter than that, you would not want that. Given the price range found there, the price on your Milwaukee seems to be reasonable. What did the test report complain about? Performance, or price compared to import bits? You've already had one suggestion to use a Unibit, and I second that. In case you don't know what they are -- they are a stepped drill bit with a single flute which is self-guiding in the metal. They come in various size ranges and step height. How thick is your steel? The steel is 11 gauge (0.12). I do know what a step-drill is, and actually have one of the DrillMaster units from HF. I have always considered it to be a bit for drilling out thin sheet metal; I originally purchased it for making knob holes in a chassis. It is good for material thickness up to the step length on the particular Unibit which you have. The one which I found appears to have a long enough step to handle your 1/8" steel. That I have had more than a couple of suggestions to use one has garenerd my attention, although I must admit a bit of skepticism as to whether or not it is the right tool considering the number of holes (60 to 80) and the thickness of material which I am looking to bore (1/8"). Try it -- you'll be surprised. Just for a test, try the smaller one which you already have and see how it performs producing holes up to 1/2" (or whatever its maximum is). In any case -- instead of using water, I would suggest Rigid high-sulfur thread cutting oil. You won't have to remove as much metal at a pass as you would with the Silver & Demming bit, so there is a greater chance that your drill press will have sufficient torque -- with the above-mentioned cutting oil refreshed for each hole. (Paint it on the unibit with an acid brush or something similar. Thanks for the suggestion, Don. I must admit that I really like water because it is cheap and is easy to flow at a volume sufficient to cool the bit and workpiece. You use it outdoors? Indoors makes a real mess since you don't have a way to capture and recycle the coolant. If you did, I would suggest you use it with a soluble oil in the water -- made for steel cutting. I have used it before with good results in cooling, but perhaps it is the lubrication ability of the bona fide product which makes it shine. The sulfur in the high sulfur cutting oil both lubricates the chips (a high pressure lubricant) and reduces the strength of the metal in shear where you are cutting. 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 --- |
#31
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Big hole, little press
Glenn Lyford wrote:
My drill press is a small bench mount Delta, with a 1/4hp motor, two inch plunge depth, and a 1/2 inch chuck. My first thought is to use a Silver and Demming (reduced shank) drill bit, 1/2" shank, 1" drill. Others have addressed the bit, and there has been passing reference to gearing down the drill press. Here's how I did that for mine: http://home.comcast.net/~glyford/js/js.htm This old article did something similar: http://www.projectsplans.com/downloa...rill_press.pdf I also second the recommendation for either a vise or clamps. If not using a vise, a block or piece of angle clamped to the table may help keep your distance in from the edge of the 3x3 consistent, only requiring you to slide it axially for each hole to line up your next mark under the bit--as long as your table doesn't swing around the column on you, such as might happen if the bit jams. Wow, thanks Glen, those are two very ingenious solutions! I really like the way yours turned out. I will definitely be making a secure jig for this operation; I don't want to get caught up in an eight-foot rotor! Jon |
#32
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Big hole, little press
DoN. Nichols wrote:
Hmm ... what kind of reamer? Single size reamers are really designed to remove very little metal from a slightly undersized hole to produce a precise hole size. I don't think that one would work well in a tri-lobed hole. Or -- if you are talking about a tapered reamer, that (under manual power) might do reasonably well. The one I'm most familiar with goes from perhaps 3/16" to 1/2" with a T-handle. There are larger ones designed to ream the ID of pipes to remove burrs. These are fitted with the square shank which fits a brace (drill holder for wood bits). That, with a brace might work well, as long as you had a way to make sure that you stop before the hole gets too large. Well, I hadn't exactly completely throught through that part of the process. I also have no experience in actually using a reamer, so you could say I am eager to get my hands on one to learn from it. But if you insist on running one -- check whether the shank has three partial flats on it. Without those, the bit is likely to bind and the shank slip in the chuck. Oh man tell me about it! This Delta of mine spins a 3/8" shiny finish when it catches at the end of a hole, and drives me NUTS! :-) Do you use the chuck key in all three positions? This makes for a somewhat better grip. Until today, I had never come across that pearl. Whatever I take away from my recent expeditions, this will remain the most valuable. If you have a milling machine and a spin indexer, you could machine your own flats on the shank if it turns out to not have them. A few years ago I tried to "roll my own" flats on a spade bit without using the above mentioned tools. You can probably guess as to how that experiment worked out. Thanks for the suggestion, Don. I must admit that I really like water because it is cheap and is easy to flow at a volume sufficient to cool the bit and workpiece. You use it outdoors? Indoors makes a real mess since you don't have a way to capture and recycle the coolant. If you did, I would suggest you use it with a soluble oil in the water -- made for steel cutting. I used it indoors at the sink for drilling 1/8" holes through the center of 1.5" long sections of 3/8" threaded rod. I had to go pretty slow once I got in, and also had to pull the bit out frequently to clear the debris, but it did work (ignoring the half-dozen mulligans). Mess was contained by setting the drill press into a plastic-sheet lined basin near the sink, so the water flowed into the drain. Here is a picture of one of the completed units in it's assembly for you to guess out the purpose: http://img15.imageshack.us/img15/7540/jonpart.jpg The sulfur in the high sulfur cutting oil both lubricates the chips (a high pressure lubricant) and reduces the strength of the metal in shear where you are cutting. Thanks Don, I will be picking up some proper cutting fluid for this job; big drill bits aren't cheap! Jon |
#34
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Big hole, little press
On 2010-04-28, Jon Danniken wrote:
DoN. Nichols wrote: Hmm ... what kind of reamer? Single size reamers are really [ ... ] Or -- if you are talking about a tapered reamer, that (under [ ... ] Well, I hadn't exactly completely throught through that part of the process. I also have no experience in actually using a reamer, so you could say I am eager to get my hands on one to learn from it. The first rule with any reamer is *never* turn it backwards. It chips the hardened cutting edge. I think that the step drill would still be the best bet for this, if you are going to pilot drill through. It will make smooth round holes. For the straight reamers, there are two styles -- the ones with the square on the end for a tap wrench which are made for hand use. They have along chamfer on the end to help getting it started cutting, assuming that your pilot hole is close to size. The other has a long round shank and is called a "chucking reamer", intended to be used under power -- often in a turret in a lathe for taking a hole to finish size just after the previous station drilled it a little undersized. It has a very short chamfer and is pretty useless under hand power. And often a bad idea in a drill press too. [ ... ] Do you use the chuck key in all three positions? This makes for a somewhat better grip. Until today, I had never come across that pearl. Whatever I take away from my recent expeditions, this will remain the most valuable. Something which I learned as a teen, back in the late 1950s. If you have a milling machine and a spin indexer, you could machine your own flats on the shank if it turns out to not have them. A few years ago I tried to "roll my own" flats on a spade bit without using the above mentioned tools. You can probably guess as to how that experiment worked out. Well -- you could do it with a file while holding the shank in a vise, but the trick is getting the three flats equally spaced around the shank. Thanks for the suggestion, Don. I must admit that I really like water because it is cheap and is easy to flow at a volume sufficient to cool the bit and workpiece. You use it outdoors? Indoors makes a real mess since you don't have a way to capture and recycle the coolant. If you did, I would suggest you use it with a soluble oil in the water -- made for steel cutting. I used it indoors at the sink for drilling 1/8" holes through the center of 1.5" long sections of 3/8" threaded rod. I had to go pretty slow once I got in, and also had to pull the bit out frequently to clear the debris, but it did work (ignoring the half-dozen mulligans). Mess was contained by setting the drill press into a plastic-sheet lined basin near the sink, so the water flowed into the drain. O.K. I hope that your drill press frame was well grounded through the power cord -- or that the outlet was equipped with a ground fault interrupter. Otherwise, you are in serious danger. Here is a picture of one of the completed units in it's assembly for you to guess out the purpose: http://img15.imageshack.us/img15/7540/jonpart.jpg Hmmm ... mounted in a piece of plexiglass with a curved edge which looks as though it may form a complete circle. 3/8" rod -- the hole you say is only 1/8". It might be the size of the center insulation of a coax cable just a bit smaller than RG-58. I think that I see the impressions of the braid in the OD. It is not precisely enough made to be a proper gas-tight seal. It looks as though you have flats filed near the end for a wrench which suggests that you are trying to adjust the extension. Perhaps some kind of spark gap, sparking against something not visible in this view. If there were metal extending beyond the insulation I would consider it an electrical feedthrough, especially since I seem to see a ghostly image of the same projection on the other side. Hmm ... perhaps the Plexiglas is a full circle, and the whole device is intended to carry a spark between electrodes spaced on either side of the Plexiglas as it rotates? BTW -- this (drilling though the center) is the kind of task which a lathe with the bit in a tailstock chuck would have been better at. Yes, keep backing the bit out (peck drilling) to clear the chips. The sulfur in the high sulfur cutting oil both lubricates the chips (a high pressure lubricant) and reduces the strength of the metal in shear where you are cutting. Thanks Don, I will be picking up some proper cutting fluid for this job; big drill bits aren't cheap! Indeed so. 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 --- |
#35
Posted to rec.crafts.metalworking
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Big hole, little press
DoN. Nichols wrote:
The first rule with any reamer is *never* turn it backwards. It chips the hardened cutting edge. I think that the step drill would still be the best bet for this, if you are going to pilot drill through. It will make smooth round holes. For the straight reamers, there are two styles -- the ones with the square on the end for a tap wrench which are made for hand use. They have along chamfer on the end to help getting it started cutting, assuming that your pilot hole is close to size. The other has a long round shank and is called a "chucking reamer", intended to be used under power -- often in a turret in a lathe for taking a hole to finish size just after the previous station drilled it a little undersized. It has a very short chamfer and is pretty useless under hand power. And often a bad idea in a drill press too. Rats, well I'll get to play with a reamer one of these days. I guess now I have another excuse to have to get a lathe. O.K. I hope that your drill press frame was well grounded through the power cord -- or that the outlet was equipped with a ground fault interrupter. Otherwise, you are in serious danger. It was, but don't forsee utilizing that setup again. It did work at the time, though. Here is a picture of one of the completed units in it's assembly for you to guess out the purpose: http://img15.imageshack.us/img15/7540/jonpart.jpg Hmmm ... mounted in a piece of plexiglass with a curved edge which looks as though it may form a complete circle. 3/8" rod -- the hole you say is only 1/8". It might be the size of the center insulation of a coax cable just a bit smaller than RG-58. I think that I see the impressions of the braid in the OD. It is not precisely enough made to be a proper gas-tight seal. It looks as though you have flats filed near the end for a wrench which suggests that you are trying to adjust the extension. Perhaps some kind of spark gap, sparking against something not visible in this view. If there were metal extending beyond the insulation I would consider it an electrical feedthrough, especially since I seem to see a ghostly image of the same projection on the other side. Hmm ... perhaps the Plexiglas is a full circle, and the whole device is intended to carry a spark between electrodes spaced on either side of the Plexiglas as it rotates? Yep, it's a spark gap, you get the cigar. This one is used for a tesla coil (they don't like you building them for transmitters anymore). http://img580.imageshack.us/img580/8080/gap04.jpg BTW -- this (drilling though the center) is the kind of task which a lathe with the bit in a tailstock chuck would have been better at. Yes, keep backing the bit out (peck drilling) to clear the chips. Indeed, and thanks! Jon |
#36
Posted to rec.crafts.metalworking
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Big hole, little press
Pete Keillor wrote:
Jon, I thought you might be interested in how I did similar. Here's links to some old dropbox posts. Issues with the bench in use: my son isn't fond of the bench, wants something with a better pad; the elevation toggle is a real pinch point; The threaded pins, while hell for stout and very secure, are slow. But it damn sure don't wiggle or flex. http://metalworking.com/dropbox/HoleJig.txt http://metalworking.com/dropbox/HoleJig01.JPG http://metalworking.com/dropbox/HoleJig02.JPG http://metalworking.com/dropbox/HoleJig03.JPG http://metalworking.com/dropbox/HoleJig04.JPG http://metalworking.com/dropbox/HoleJig05.JPG http://metalworking.com/dropbox/HoleJig06.JPG http://metalworking.com/dropbox/HoleJig07.JPG http://metalworking.com/dropbox/WeightBench.txt http://metalworking.com/dropbox/WeightBench02.jpg http://metalworking.com/dropbox/WeightBench08.jpg http://metalworking.com/dropbox/WeightBench09.jpg http://metalworking.com/dropbox/WeightBench12.jpg http://metalworking.com/dropbox/WeightBench13.jpg http://metalworking.com/dropbox/WeightBench16.jpg http://metalworking.com/dropbox/WeightBench17.jpg Wow, thank you Pete, you did a phenomenal job on that. There will come a day, not too far off in the future, when it dawns on your son that there is no other bench he would rather work at. I really like how you tackled the flat bench to incline bench transition, your solution is both elegant and simple by using the nested tubing. I have been struggling to come up with an acceptable solution, and I think I'm going to steal your idea. Thanks! Jon |
#37
Posted to rec.crafts.metalworking
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Big hole, little press
Cutting some flats on drill shanks can be aided with a spare chuck and/or a
big hex nut on the opposite end for indexing the 3 positions. A magnetic pointer made from wire, and attached to the vise or other drill-holding part, can be used for a reference point. One could choose a feature on the drill chuck that appears in 3 positions, or the points of a big hex fastener coupled to the drill to index each position. A relatively simple fixture consisting of an adjustable slide could simplify the 3 flats grinding task with the flats being a more precisely uniform depth. Making the flats the same depth is also practical, otherwise the drill point may orbit around the drillpress spindle's axis. The commonly available stones for rotary tools such a Dremel have abrasive that's so fine, that it's not likely one would accidentally grind off too much material. Checking the flats' depths with a caliper or micrometer would gage uniformity. -- WB .......... "DoN. Nichols" wrote in message ... A few years ago I tried to "roll my own" flats on a spade bit without using the above mentioned tools. You can probably guess as to how that experiment worked out. Well -- you could do it with a file while holding the shank in a vise, but the trick is getting the three flats equally spaced around the shank. |
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