Home |
Search |
Today's Posts |
|
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. |
Reply |
|
LinkBack | Thread Tools | Display Modes |
#1
Posted to rec.crafts.metalworking
|
|||
|
|||
Countersinking with a too-fast drill press
In June 2005, I was having problems because my little 12" Delta
variable-speed drill press has a minimum speed of 500 rpm, which was a real problem, especially when countersinking. I had found an interim solution for larger holes: Put the countersink in the hole and turn power on, releasing the downward pressure before the press gets up to speed. This did not work with small holes, and the 1/4-inch severance countersink, working in 6061 aluminum, flooded with a water-based coolant. I would have thought that a small countersink would be OK at 500 rpm, but the holes became ragged and misshapen. Countersinking with a hand drill did work, making pretty holes, but yielded inaccurate countersinks because it's so hard to drill straight by hand. I was busily tearing metal and hair when it occurred to me that tapping is an extreme kind of machining, and yet one can get clean threads, with the right lubricant. So I tried LPS Labs' "Tap-All". It worked, even at 500 rpm. Haven't tried it in steel and/or for large holes yet. Joe Gwinn |
#2
Posted to rec.crafts.metalworking
|
|||
|
|||
Countersinking with a too-fast drill press
"Joseph Gwinn" wrote in message ... Haven't tried it in steel and/or for large holes yet. If I had to bet money, I'd say you're not feeding fast enough (pushing hard enough). You should be able to countersink a 1/2" hole in steel at 500 RPM with some practice. You have to feed *hard* into the material (you'll need a good chuck as most countersinks have pretty hard shanks) and retract quickly when you're at the desired depth - no dilly-dallying at the bottom or throughout the cut. Your idea about the lube is good. Countersinks are easy to burn and hard to sharpen. HTH. Regards, Robin |
#3
Posted to rec.crafts.metalworking
|
|||
|
|||
Countersinking with a too-fast drill press
In article , Joseph
Gwinn says... I had found an interim solution for larger holes: Put the countersink in the hole and turn power on, releasing the downward pressure before the press gets up to speed. I used to do this at work. Basically you are using the start windings and the mechanical inertia of the spindle and motor to keep things down to a slow enough speed that the c'sink doesn't chatter. It also helps to use a single flute countersink. Eventually I went with a VFD so now I can run those things slower than I would want to - if I wanted to, if you catch my drift. Jim -- ================================================== please reply to: JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com ================================================== |
#4
Posted to rec.crafts.metalworking
|
|||
|
|||
Countersinking with a too-fast drill press
In article ,
"Robin S." wrote: "Joseph Gwinn" wrote in message ... Haven't tried it in steel and/or for large holes yet. If I had to bet money, I'd say you're not feeding fast enough (pushing hard enough). You should be able to countersink a 1/2" hole in steel at 500 RPM with some practice. You have to feed *hard* into the material (you'll need a good chuck as most countersinks have pretty hard shanks) and retract quickly when you're at the desired depth - no dilly-dallying at the bottom or throughout the cut. How do you keep from boring too deep? I guess one chews one hole up finding the right depth to set the depth limit stop to. Not that I trust the depth stop to really prevent motion when pushed hard enough to avoid chatter. This approach probably works better for large holes than for small ones. Your idea about the lube is good. Countersinks are easy to burn and hard to sharpen. Haven't burned one yet - probably too chicken to push it that hard. Was in a used tool place last week. Saw a 3/8 mill with irregular heat colors, signs of heavy use in aluminum, and a bit of solidified aluminum "soldered" to one flute. My guess is that it was on a CNC mill happily hogging aluminum when the coolant flow failed. Joe Gwinn |
#5
Posted to rec.crafts.metalworking
|
|||
|
|||
Countersinking with a too-fast drill press
--Plan B: go to the swapmeet and pick up a brace and bit; these
work OK for this sort of thing and they're *great* for tapping.. -- "Steamboat Ed" Haas : Bummed to be living in the Hacking the Trailing Edge! : Golden Age of Bull****... http://www.nmpproducts.com/intro.htm ---Decks a-wash in a sea of words--- |
#6
Posted to rec.crafts.metalworking
|
|||
|
|||
Countersinking with a too-fast drill press
If you are able to vary the voltage to your DP, you will at least have more
controllable torque at the motor, and can likely keep the speed constant at a given pressure. Proly not the greatest thing for the motor over prolonged periods, but for a duty cycle of, say, 20%, it should be OK. A variac would do, or a big-assed dropping resistor. Or, perhaps just two motors in series--a spare motor in series w/ your DP motor! ---------------------------- Mr. P.V.'d formerly Droll Troll "Joseph Gwinn" wrote in message ... In June 2005, I was having problems because my little 12" Delta variable-speed drill press has a minimum speed of 500 rpm, which was a real problem, especially when countersinking. I had found an interim solution for larger holes: Put the countersink in the hole and turn power on, releasing the downward pressure before the press gets up to speed. This did not work with small holes, and the 1/4-inch severance countersink, working in 6061 aluminum, flooded with a water-based coolant. I would have thought that a small countersink would be OK at 500 rpm, but the holes became ragged and misshapen. Countersinking with a hand drill did work, making pretty holes, but yielded inaccurate countersinks because it's so hard to drill straight by hand. I was busily tearing metal and hair when it occurred to me that tapping is an extreme kind of machining, and yet one can get clean threads, with the right lubricant. So I tried LPS Labs' "Tap-All". It worked, even at 500 rpm. Haven't tried it in steel and/or for large holes yet. Joe Gwinn |
#7
Posted to rec.crafts.metalworking
|
|||
|
|||
Countersinking with a too-fast drill press
Joseph Gwinn wrote:
I would have thought that a small countersink would be OK at 500 rpm, but the holes became ragged and misshapen. Yes, it is. As others sayd: More feed. Most people fear to feed countersinks and think the have to go sloooow. Noooo. :-) The first few 1/10mm feed fast, and then you can go back with feed. This helps. If you have chatter, I guess your DP's table is not clamped (and so swinging a tad left/right). Fix that. Also, clamp your part to countersink in a (heavy) vice, and I bet your problem is gone. Nick -- Motor Modelle // Engine Models http://www.motor-manufaktur.de DIY-DRO - YADRO - Eigenbau-Digitalanzeige |
#8
Posted to rec.crafts.metalworking
|
|||
|
|||
Countersinking with a too-fast drill press
In article ,
steamer wrote: --Plan B: go to the swapmeet and pick up a brace and bit; these work OK for this sort of thing and they're *great* for tapping.. A brace and bit! Actually, I have one that I bought new in the late 1960s. Used it mostly for installing locks - it's the best way to cut a clean 1-1/8 inch hole in a wood door without power tools. The trick was to bore until the lead screw just poked through the back side, back out, and complete the cut by boring from the back. I hadn't thought of using it for tapping. It ought to work, at least for larger sizes. If I can keep the tap properly aligned by hand. What I've been using is a piloted tap wrench in the drill press. Joe Gwinn |
#9
Posted to rec.crafts.metalworking
|
|||
|
|||
Countersinking with a too-fast drill press
"Joseph Gwinn" wrote in message ... I hadn't thought of using it for tapping. It ought to work, at least for larger sizes. The larger the tap, the greater the torque requirement (large at work is M36). Could be difficult. If I can keep the tap properly aligned by hand. What I've been using is a piloted tap wrench in the drill press. You should try a spiral-point tap, in the drill chuck. Ideally your drill press reverses to pull the tap out. Probably still faster than hand tapping if you can only run the tap under power forwards. Regards, Robin |
#10
Posted to rec.crafts.metalworking
|
|||
|
|||
Countersinking with a too-fast drill press
In article ,
"Robin S." wrote: "Joseph Gwinn" wrote in message ... I hadn't thought of using it for tapping. It ought to work, at least for larger sizes. The larger the tap, the greater the torque requirement (large at work is M36). Could be difficult. So far, I have not needed to go beyond 3/8-16 and M8-1.25, but I have a few 1/2-13 taps ready to go. If I can keep the tap properly aligned by hand. What I've been using is a piloted tap wrench in the drill press. You should try a spiral-point tap, in the drill chuck. Ideally your drill press reverses to pull the tap out. Probably still faster than hand tapping if you can only run the tap under power forwards. I do use spiral-point taps, and gun taps, but only by hand so far. Isn't 500 rpm a bit fast for a tap? How do you stop in time? I have also been using a thread-forming 10-32 tap for some very deep blind holes in aluminum. I had been using various kinds of cutting taps, but it was touch-and-go, and I did break a few taps until switching to thread-forming taps for this job. None of the broken taps were Asian. Some were Greenfield, and some were Sossner (sp?). Joe Gwinn |
#11
Posted to rec.crafts.metalworking
|
|||
|
|||
Countersinking with a too-fast drill press
|
#13
Posted to rec.crafts.metalworking
|
|||
|
|||
Countersinking with a too-fast drill press
Joseph Gwinn wrote:
Everything was clamped, but the misshapen hole was in a 3" disk made of 0.060" sheet, which is hard to really clamp. OK, this is nearly impossible with the 3 flutes countersinks. You need one with one flute of the type with one diagonal hole. They are good for deburring, but in a material so thin, you are deburring. Nick -- Motor Modelle // Engine Models http://www.motor-manufaktur.de DIY-DRO - YADRO - Eigenbau-Digitalanzeige |
#14
Posted to rec.crafts.metalworking
|
|||
|
|||
Countersinking with a too-fast drill press
Joseph Gwinn wrote:
: I do use spiral-point taps, and gun taps, but only by hand so far. : Isn't 500 rpm a bit fast for a tap? How do you stop in time? --Well if this is a money making proposition and you plan to make bunches you might want to invest in a Tapmatic. Once you use one of these beauties you'll wonder how you got along without one for so long. OTOH they ain't cheap.. -- "Steamboat Ed" Haas : Bummed to be living in the Hacking the Trailing Edge! : Golden Age of Bull****... http://www.nmpproducts.com/intro.htm ---Decks a-wash in a sea of words--- |
#15
Posted to rec.crafts.metalworking
|
|||
|
|||
Countersinking with a too-fast drill press
If I had to bet money, I'd say you're not feeding fast enough (pushing
hard enough). You should be able to countersink a 1/2" hole in steel at 500 RPM with some practice. I'd bet that the drill press would probably stall with the necessary amount of pressure being applied. -- Regards, Joe Agro, Jr. (800) 871-5022 (908) 542-0244 Automatic / Pneumatic Drills: http://www.AutoDrill.com Multiple Spindle Drills: http://www.Multi-Drill.com V8013-R |
#16
Posted to rec.crafts.metalworking
|
|||
|
|||
Countersinking with a too-fast drill press
In article A93jf.226$xY2.167@trndny08,
"Joe AutoDrill" wrote: If I had to bet money, I'd say you're not feeding fast enough (pushing hard enough). You should be able to countersink a 1/2" hole in steel at 500 RPM with some practice. I'd bet that the drill press would probably stall with the necessary amount of pressure being applied. I bet you are right, given my cute little drill press. Not that I've managed to stall it yet. Usually, the drill bit slips in the chuck. Joe Gwinn |
#17
Posted to rec.crafts.metalworking
|
|||
|
|||
Countersinking with a too-fast drill press
If I had to bet money, I'd say you're not feeding fast enough (pushing
hard enough). You should be able to countersink a 1/2" hole in steel at 500 RPM with some practice. I'd bet that the drill press would probably stall with the necessary amount of pressure being applied. I bet you are right, given my cute little drill press. Not that I've managed to stall it yet. Usually, the drill bit slips in the chuck. Are there countersink tools available with three flats on the shank? -- Regards, Joe Agro, Jr. (800) 871-5022 (908) 542-0244 Automatic / Pneumatic Drills: http://www.AutoDrill.com Multiple Spindle Drills: http://www.Multi-Drill.com V8013-R |
#18
Posted to rec.crafts.metalworking
|
|||
|
|||
Countersinking with a too-fast drill press
In article aQhjf.103$R02.75@trndny06,
"Joe AutoDrill" wrote: If I had to bet money, I'd say you're not feeding fast enough (pushing hard enough). You should be able to countersink a 1/2" hole in steel at 500 RPM with some practice. I'd bet that the drill press would probably stall with the necessary amount of pressure being applied. I bet you are right, given my cute little drill press. Not that I've managed to stall it yet. Usually, the drill bit slips in the chuck. Are there countersink tools available with three flats on the shank? I imagine that there are, but I haven't seen them. I imagine that the better grade of countersinks do not have the flats, the expectation being that one will use a better grade of chuck to match. My solution was to upgrade the chuck. I'd love to get a ball-bearing Jacobs chuck, but have not seen it offered with a J33 taper, only J3 and the like. My next drill press will not have J33 taper - too limiting. Joe Gwinn |
#19
Posted to rec.crafts.metalworking
|
|||
|
|||
Countersinking with a too-fast drill press
According to Joseph Gwinn :
In article aQhjf.103$R02.75@trndny06, "Joe AutoDrill" wrote: [ ... ] Are there countersink tools available with three flats on the shank? I imagine that there are, but I haven't seen them. I imagine that the better grade of countersinks do not have the flats, the expectation being that one will use a better grade of chuck to match. My solution was to upgrade the chuck. I'd love to get a ball-bearing Jacobs chuck, but have not seen it offered with a J33 taper, only J3 and the like. My next drill press will not have J33 taper - too limiting. Doesn't your drill press have a Morse taper spindle? And how about your next one? If so, you can adapt it for almost *any* Jacobs taper. 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 --- |
#21
Posted to rec.crafts.metalworking
|
|||
|
|||
Countersinking with a too-fast drill press
"Joseph Gwinn" wrote in message ... Comments? All our drill presses at work have gear-driven power feeds. I don't know how much drilling you do or what you're drilling but I can't imagine not having the power feed. Regards, Robin |
#22
Posted to rec.crafts.metalworking
|
|||
|
|||
Countersinking with a too-fast drill press
Doesn't your drill press have a Morse taper spindle? And how
about your next one? If so, you can adapt it for almost *any* Jacobs taper. No. None of the current Delta drill presses do, even the large ones. One of the reasons I often refer to it as "cute"; it's not a compliment. So much for Delta. My next drill press *will* have a morse taper spindle. (Or will be a mill-drill with R8 spindle.) What about the Delta 70-200 and/or 17-968? I'm almost sure the 70-200 has one (might be a discontinued model) and a customer of ours just bought a large number of heads for 17-968's and told us it has a MT... I sure hope he is right!!! Anyhow... Maybe one of these will work for you? -- Regards, Joe Agro, Jr. (800) 871-5022 (908) 542-0244 Automatic / Pneumatic Drills: http://www.AutoDrill.com Multiple Spindle Drills: http://www.Multi-Drill.com V8013-R |
#23
Posted to rec.crafts.metalworking
|
|||
|
|||
Countersinking with a too-fast drill press
In article e6Ilf.13559$Qf5.2621@trndny07,
"Joe AutoDrill" wrote: Doesn't your drill press have a Morse taper spindle? And how about your next one? If so, you can adapt it for almost *any* Jacobs taper. No. None of the current Delta drill presses do, even the large ones. One of the reasons I often refer to it as "cute"; it's not a compliment. So much for Delta. My next drill press *will* have a morse taper spindle. (Or will be a mill-drill with R8 spindle.) What about the Delta 70-200 and/or 17-968? I'm almost sure the 70-200 has one (might be a discontinued model) and a customer of ours just bought a large number of heads for 17-968's and told us it has a MT... I sure hope he is right!!! Anyhow... Maybe one of these will work for you? Hmm. I don't recall seeing these before on Delta's website, but I'll look again. Actually, I wasn't looking at 20" units then, and that may be the key. Delta 70-200 looks possible. It's a 20" metalworker's drill press. It has a MT-3 to J33 adapter, with a J33 chuck, and a T-slot table. Min speed is 150 rpm. The drive is step pulley, 110/220, single phase. Single phase. Wonder if it also comes in three phase, so I can implement variable speed using a VFD. Switching belts on pulleys is pretty slow. Delta 17-968 is a 17" woodworkers unit, and so has the wrong kind of table, and a single-phase motor. However, it has the same MT-3 to J33 adapter plus J33 chuck. Delta 70-200 is still listed at http://www.deltamachinery.com, and three phase appears to be available. Don't know how I missed it. Hmm. Thanks, Joe Gwinn |
Reply |
Thread Tools | Search this Thread |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Forum | |||
Funny lathe machining problem.... | Metalworking | |||
Keyless Chuck for Drill Press | Woodworking | |||
Bench-top drill press recommendation? and what I found so far. | Metalworking | |||
Is Drill Doctor worth the price???? | Metalworking | |||
slowing my drill press | Metalworking |