"Precision" Pin Vise

Are there any pin vises suitable for CNC drilling at high speeds for micro
drills. A high quality high precision pin vise.
I know. I know. Sounds like an oxy moron. I think if I can find a pin
vise that will actually hold the bits straight, and has low enough runout,
it will be possible with correct speed and feed calculations.
I bought two mid price pin vises from two different sounces, and
unfortunately neither holds a drill bit particularly straight.
In the mean time I ordered some carbide micro drills in the sizes I need,
but because of their DOC capabilities, I'll need to back drill the part.
Oh, joy. A secondary setup for a part what fun. LOL.
FYI: Did some tests with what I had and found HSM Adviser wanted to feed
way to fast. As a check I plugged the same numbers into ME Consultant, and
it indicated less than half the feed rate of HSM. The HSM numbers flexed
and broken drill bits very quickly. Haven't retried yet with the ME
numbers.
Reply to
Bob La Londe
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I think (in printed circuit board drilling) the usual scheme is to use a collet (0.125") and a suitable shank size on the microdrill. So, does a collet chuck work for you? I'm dubious that a 'pin vise' is going to be well enough balanced to run at the high RPMs a microdrill calls for.
Reply to
whit3rd
And, while those solid carbide drills will break if you even look at them t oo hard, many people (myself included) have had good success running them i n dremel tools in dremel drill presses. Though I never measured it, that ma kes me think that the runout of the dremel and its collets is pretty good.
If you don't want to cobble up a dremel tool holder for your mill, maybe yo u could sacrifice a dremel tool and use its shaft in place of your pin vice ?
Reply to
rangerssuck
If he is looking for an small adjustable chuck Dremel has one that might work:
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Obviously made for high RPM but who knows on runout... Only ~$9 though.
Reply to
Leon Fisk
I've always used these drills in collets. I do have one of the little chucks and it's pretty good, but I don't know that it's good enough.
There's got to be a bunch of busted dremel tools out there - bad bearings, bad motors, bad speed controls. Ought to be able to find one super cheap.
Reply to
rangerssuck
Do you have a Morse or other taper in the drilling machine ? if so get a high quality collet holder and double angle insert in 1/8 or whatever the actual diameter is.
The big question is the drilling machine has bearings that will keep the drill stable at speed ?
If you don't have a taper in the drilling machine - they make holders with round shafts.
If you get a round shaft with a flat, that flat aligns with a hole in the chuck if held that way or not on a jaw.
Martin
Reply to
Martin Eastburn
I'd use HSS bits on this. Maybe Cobalt? I'll bet they last longer than the carbide bits.
FWIW I read in The Machinery Handbook that the TIR of small high speed bits should be less that 1/100 of the bit diameter.
Reply to
gray_wolf
Pin vises are hand held tools.
A pin CHUCK on the other hand is designed to hold tiny bits and be spun under power.
Like these.
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I have had the B&S set for a long time, they run very true.
Reply to
Steve W.
I've got a No. 0 Jacobs chuck that I use for small drills. Is that still too big?
George H.
Reply to
ggherold
This machine has an ER11 spindle nose. I would just get ER11 collets for each drill size, but anything under 1/8" is pretty much impossible to get out of the nut again. Heck, pretty darn impossible to get into the nut. The 1/8" I use everyday hasn't been out of the nut since I installed it. I'm just glad I had spare collet closer nuts on hand when I discovered it.
I spin it at 24K everyday with endmills as small as .026. I figured 10-12k would be a good starting point for these tiny drills if I can get the feed right. Torque drops effectively to about zero on this spindle around 8K.
I was actually looking for one, but so for those I have purchased have been pretty much garbage. Nowhere near concentric enough. I thought a pin vise might do the trick, but even if you get the drill engaged with all 4 points you can see its not straight on those I have tried so far. They tend to be slightly better with largers bits in the 61-70 ranges, but under 70 they are crap.
This application is for venting features in a mold that can not vent to the parting line. Since its a very soft plastic I plan to drill vent the features (before cutting the cavity) and blow the holes out with air after each injection. I can back drill for clearance to the back side of the plates for a prototype, but if I am successful and wind up producing these in any quantity the extra setup to do that cleanly will add substantially to the time and cost.
Carbide 1/8" shank drills will only take me down to a depth max of about 3/8". Less on smaller bits. The plates are 1/2" thick to accomodate the standard 5/8" injector nozzle for this type application. (1/2+1/2).
Reply to
Bob La Londe
"Bob La Londe" fired this volley in news:nb9sg7$o0n$1 @dont-email.me:
Yep, but inertia plays an important role in drilling those little holes!
Lloyd
Reply to
Lloyd E. Sponenburgh
But you indicated this was for NC machining? So, can you pre-drill 0.250" deep with a 0.130" diameter bit, then sink the microdrill the rest of the way? I foresee some chip clearance issues still, but pecking might work.
Reply to
whit3rd
I have a Doall drill that uses a No. 0 Jacobs chuck. Runs 0-20,000 or 0-30,000 RPM. No noticeable runout and doesn't break bits. Have not used it on really small bits, but the chuck does completely close, so bits size 80 or so should work.
Paul
Reply to
Paul Drahn
Great idea, with some changes for drill bits you can actually buy. With a d rill such as
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you could dr ill .130 dia .320 deep, hold .980 of the bit's shank in the collet and dril l the remaining .180 and still have .010 clearance between the collet and t he work, and .010 of flutes left over.
Probably better to drill the shank clearance holes as deep as possible, min imizing the depth of the tiny hole. There is a LOT of shank available (1.31 ") on these drills.
Reply to
rangerssuck
I did look up the Jacobs 0 chuck but couldn't confirm it would work under your conditions, and it's expensive. The minimum drill shank size is 0.0135".
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--jsw
Reply to
Jim Wilkins
Pin vises which I have seen typically have knurled shafts, which makes it more difficult to mount them truly on center.
What *I* would use is one of the smallest Albrecht drill chucks. I've found the 0-1/8" ones to work well down to the smallest number drills that I have (#80), both in a Cameron Precision sensitive drill press, and in the tailstock of an Emco-Maier Compact-5/CNC lathe.
From a search for Albrecht chucks, I find this description;
====================================================================== The Albrecht 70020 C30-J0 Classic Keyless Drill Chuck has a 0.015" to 1/8" ======================================================================
This is the one with a J0 taper.
There is also a smaller one -- 15-J0 -- maximum capacity of 1/16"
Both are small enough to handle rather elevated RPMs.
Enjoy, DoN.
Reply to
DoN. Nichols
I haven't seriously looked for an arbour for the one I have, O just find it VERY useful as a pin vise
Reply to
geraldrmiller
I had thought of back drilling he mold, and then flipping the plate to front drill the vents before cutting the cavity, but I suppose I could back drill both the clearance hole and the vent hole. I still have to do two setups for every plate, but I guess if I plan for it I can make that a little less tedious to index.
Now that I think of it even on the 1/8 shank micro drills most the have enough extra shank in front of the depth collar. If I gotta back drill it anyway, might as well do it all at once.
Reply to
Bob La Londe
They are pricey aren't they? Still not much more than a name brand integral shank chuck.
Now to see if I can find a J0 sto .250 stright shank adaptor. LOL.
Actually I think for now I am going to stick with 1/8 shank carbide micro drills, and back drill a clearance hole, then the vent hole.
I will want one of those chucks in my arsenal though. As soon as I find the taper adaptor.
Reply to
Bob La Londe
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Yep -- and really good quality.
Hmm ... search through MSC shows several 3/8" shank to JT0, including at least one by Albrecht -- to match the quality of the chuck for $48.37.
Or -- a cheap import one for $13.88, or an AcurPro for $14.47 -- almost as cheap.
So -- the question is whether you could make it work with a 3/8" shank instead?
Good Luck, DoN.
Reply to
DoN. Nichols

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