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.
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.
turn E/F upside down with .100 in chuck?
Somebody must have thought of this, I've never seen it in my short
its a bit "touchy" & would not recommend running it much more than 1K,
but its close enough for most government type edge finder work.
Only drill chucks in our shop are morse and reside in lathe tailstocks and
in an old post drill that we only use for pressing light fit dowells.
As for edge finders, one has CAT40 shank and the other one is BT.
Sounds like your shop lacks some ancillary equipment? <g>
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
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! <g> Dont replace the jaws / shank or take them apart clean & grease'em,
nay, just get $holders$ to keep tooling in them permanent & running
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.
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
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
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
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.
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.
What effect does run-out have on an edge finder?
Yesterday I made a $5.00 bet with another machinist, here is what it
Picture a 1/2" shank edge finder (.200 tip) in an ER 32 collet
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
finder and the collet to simulate some severe runout. Re edge-find
same edge of the same part as before. Look to see how far off the
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? <g>
OK, here's what happened with the bet at work today. I took a
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
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
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
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
.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
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
edge find. He was convinced, and took his loss gracefully. A fine
was had by one and all. LOL
BTW, I plan to use my windfall profits to buy donuts for the
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...
Here's another video:
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?
Not sure I understand your question. Are you talking about calculating
the center of the spindle or the run out of a tool?
As shown the edge finder or wiggler with spindle turning method is
determining the center of the spindle (not tool run out).
Using an electronic edge finder or some other method where the spindle
is NOT turning, then yes chuck, collet (tool) run out is a concern.
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<g>
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