Your using a 3/8 - .100 edge finder working off edges of blocks.
1/4"cap drill chuck in the spindle - gotta edge find the block. Whadya do? Take the chuck out.....get 3/8 collet.....put E/F in....ect (I'm spoiled- last shop had power drawbars) Happens all the time.
BRIGHT IDEA!
turn E/F upside down with .100 in chuck?
Somebody must have thought of this, I've never seen it in my short
30yrs.
its a bit "touchy" & would not recommend running it much more than 1K, but its close enough for most government type edge finder work.
Sounds like your shop lacks some ancillary equipment? Whats a machine shop with out some type of manual milling machine. Some places are going this way- all CNC. Hell nowdays if your CNC's are running, you'd better be doing some manual work or programming the next job. I know, some shops "hate" drill chucks? Everything is colleted. It is nice having R8 collets every 1/32. Why? because someone put an E/M in the chuck & scewed it up by side milling?- Its tough to use a drill chuck that runs out. Just better eliminate them! Dont replace the jaws / shank or take them apart =3D clean & grease'em, nay, just get $holders$ to keep tooling in them permanent & running true.
needless to say, I've collected a few drill chucks over the years. The one I miss is the 1/8-5/8 Albright keyless. Either I left it somewhere or somebody took a liking to it.
He has one, but it's usually sitting in a chair reading usenet groups. It's very versatile, though. It's one of the few manuals I've seen that can deburr parts AND grow tomatos.
I never tried putting an endmill in a jacobs; but I wouldn't doubt a co-worker having tried it (always taking shortcuts against advice)- but doing so would screw it up ? how ? overtightening the jaws perhaps ?
I imagine if the end mill was really working hard it could pull the chuck right off its tapered seat. I'm not sure what will happen as I've never done milling with a drill chuck, but back when Precision Mold was in business using an end mill in a drill chuck would get you fired right then and there.
Much side loading at all and you will probably deform the ( rather soft) taper shank causing the chuck to run out from that day on...though, oftentimes if a chuck runs out you can mount it upon a new shank and all is dandy....
Also, your endmill will tend to *really* want to slip up and down in the chuck jaws under even the slightest provocation which quite possibly will damage your workpiece as well as ruin the endmill and probably your chuck jaws too.
In my years as a machinist on the floor, most shops would walk you to the door if you put an endmill in the drill chuck. I know for some it may make sense to put a small one in just to do a light spot face. But rule of thumb was absolutely no endmills in chucks.
Never ran a drill press? Needed a weird size c-bore- like metric?(re- re-re ground 2flt'rs work great) Or in the lathe tailstock ? Only plunging now, no side milling Alice. Oh well.......... I can find the door myself
drill press ? nah, just learned cnc programming in a classroom for a few months and went on to work in the shops.VMCs.can't have everything handed on a silver platter.
The "science" behind not using an edgefinder in a chuck is run-out. Ex: If the thing runs out .010 at the end, then when you shift the .
100 to center, you're short. Yes, edgefinders are not meant to replace an indicator but... it's just the way things used to be in the shops I worked. The endmill in the chuck is obvious. As a test, ask one of your coworkers if you can borrow their personal drill chuck to use with an endmill. If it's their good one, expect them to turn you down.
Yesterday I made a $5.00 bet with another machinist, here is what it entails. Picture a 1/2" shank edge finder (.200 tip) in an ER 32 collet holder. Find the edge of a part to the nearest .0001, zero the axis. Take out the holder and put a narrow .010 brass shim between ONE side of the edge finder and the collet to simulate some severe runout. Re edge-find the same edge of the same part as before. Look to see how far off the axis reading is from before. I said it will probably be within .001 of the prior reading. We didn't have time to physically test this yesterday, but probably will Monday. Will I be $5.00 richer, or should I go try to dig up 500 pennies to pay off my gambling debt?
BottleBob ]
The results:
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OK, here's what happened with the bet at work today. I took a
1/2" shank edge finder and put it in an ER-32 collet holder (made sure everything was clean with no mico chips that I could see), scaled the edge finder 1" from the top of the collet (I wanted to minimize any possible exaggeration if the collet taper or holder taper were off a little bit. Cleaned the spindle. Indicated a 1-2-3 block in the vise and cleaned out the spindle taper and installed the holder and edge finder. Called over my betting opponent and a witness that held the money, just a formality. Brought the Z axis down to -9.880 (recorded that figure so I could come to the same setting later), edge found the
1-2-3 block and zero'd the readout. Took the holder out of the machine and turned it 180 degrees to see if there was a difference, it was off about a .0001, no biggie. Took the tool holder out and went and made up a .015 think brass shim. The shim was about .400 wide and a little longer that the collet, I pre-bent it in a V-block with a transfer punch. Put the shim and the edge finder in the collet, not an easy fit, scaled the edge finder 1" from the collet. Tightened it up and went to the machine with my entourage. Brought the Z down to -9.880 and fed the edge finder over in .010 increments, then .001 increments, then .0001 increments until it kicked out. It ended up being .0001 different than the original edge find. Much cheering, dancing, and commotion was seen and heard coming from MY corner! My betting buddy was pretty convinced but he wanted to try it in a drill chuck (just in case I had rigged the collet to tilt the precise amount the get my reading), we put the shim on one of the three chuck jaws, inserted the edge finder, tightened it, and went back to the machine. To make a long story short it was out .0002 from the original edge find. He was convinced, and took his loss gracefully. A fine time was had by one and all. LOL BTW, I plan to use my windfall profits to buy donuts for the shop tomorrow morning. Donuts are not bought on a regular basis, but every couple of months someone brings some in. Thanks to all who chipped in with comments.
now that IS interesting; makes sense in a weird way, I can imagine the runout as orbiting the centerline of the collet, so the center remains constant. An experiment I'll have to try for myself if I ever get the time with a "good" machine.
Yup--but with the ball wiggler, any spindle ( or toolholder ) runout whatsoever is totally eliminated due to the probe having a spherical shape and it's being mounted underneath a swivel.....which allows an angular offset to occur at the swivel joint in an amount which is exactly opposite to the chuck runout....even 1.500" tir of chuck runout presents zero problem with a ball system...
I can appreciate the point, buttttt not knowing the runout how do you know the offset when you cannot check against a known location ? is there a technique to this, am I missing something or that is a common limitation for all things?
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