Drill Chuck Runout Testing

[knudsen]

... or the obsessions of a madman.

In this thread, we decided I would check the runout of my new Enco keyless chuck. On the 2nd page a setup was suggested by gentleman Nateg281.

While I was all setup to do it, I measured all the drill chucks I could find that weren't mounted to a hand drill or DP. The results are in!

The setup, I first eyeballed, then indicated, the DTI'd my "test bar" a rotor shaft for a 30K RPM mixer. I figured that would be pretty straight! Measuring at each jaw of the 4 jaw, I got it well under the half thou resolution of the DTI, eyeballed at about 1/4 thou. I got the same running the lathe at a few rpms or turning it by hand. Unfortunately, I didn't notice the autofocus gods were not smiling, and it's not focused on the dial. I first dialed in the chuck at the end of the rod, then moved in and verified the readings were the same. Until the last couple of tests, I rechecked the runout of the test bar after every chuck.

[knudsen]

Keyless Drill Chuck Maximum Capacity: 5/16 Minimum Capacity: 0 Mount: 1JT

I was happily surprised to see only .001 runout. I measured at the outer edge of the taper, about 1/4" in, and as far as I could reach with the DTI. I lost the picture, but unhappily surprised that it jumps up to about .0025 to .003 with the cheap Enco arbor.

[knudsen]

This is part of the $99 Speedway Series 7 Piece Metal Lathe Accessory Kit #4705, so I don't know what it costs. The kit as a whole is a bargain, and I managed with this chuck for 14 years.

It came in at just under .005 off the MT2 arbor. If the Enco arbor is indicative, at least half of the runout is the arbor. Anything requiring this large of a chuck, I'll usually bore. So with my new keyless, this rascal is semi-retired.

[knudsen]

Got this from a retired machinist at PM a great place to pick up used stuff. The Albrecht is gone, I already asked Look daily if you want stuff, or you'll go bonkers over what you missed.

Disappointing to see her come out at .002. I might try turning down the arbor, but I think it might need jaws or I might need to clean something. I had a much lower reading on the mill when I bout the chuck last year.

[knudsen]

Can't find it on their site, was on sale and maybe closeout. I bought it for a hand drill and that's about all it's good for by my tests. .009 on the outside and .007 on the inside. You would want to index to one of these surfaces if you were to mount it on a machine, as it is a threaded mount.

[knudsen]

Don't remember where, when or how much. It's been bouncing around in my tool chest for years. .005

(Arbor is a failed attempt and I didn't even try reading it)

[knudsen]

Picked it up at this place where the biz owner donates 3/4 of his building to a perpetual yard sale for the big brothers program. It was all rust when I bought it, soaked it in Kroil for a week. I've picked up tons of goodies there for $5 or $10 and it all goes to a great cause.

If it was any older it would be made of stone. I was surprised to see as good as .012 out on the old arbor, then for giggles, I measured the outer edge and found under .006! Not bad for an old goat. This is the type that the threaded rod pushes the jaws out as you thread it in by turning the whole chuck. The arbor is designed to mount directly to a motor and hold a wire wheel or polishing pad between the cups, then you can chuck up a wire brush, polishing pad, sanding disk, or whatever. This is how I planned to use it, but maybe I should use the chinese Jacobs for that and keep this for something important! LOL

[knudsen]

(Can't Remember A F'n Thing)

Forgot, I have a 1/4" version of the last one I tested, on my hurdy gurdy, the original and ultimate cordless drill!

Also, couldn't find my big honker that came with the x2. Haven't used it since I bought the Rohm, and don't intend to. I'll use a collet for big stuff.

And of tests.

[TroyO]

Hey, very cool! You look almost half set up to trim the tapers for dern near zero runout, too.

I was considering something similar on an R8 that was swinging egg shaped... Zero on the chuck side, then use a DTI on the tapers to get the compound running paralell to it and taking off a skin cut to true it up.

Ends up I was too lazy, LOL... a R8/JT33 was like $10

But, I figure having the old arbor as a doner for something will come in handy too.

[japroach]

nice, thanks for measuring

[knudsen]

It was a fun evening I couldn't find my R8 5/8 keyed chuck, but I was thinking, that sharp tapered part of the R8 is what you would want to measure, but wouldn't we have to do some math to compensate for the taper if the DTI is perpendicular to that edge? I think if it were perpendicular to the axis, it would be tough to get a good response with the side load it would put on the DTI arm. I hate that word, thank God for spell checker.

[TroyO]

You would have to make sure you were reading on center of the taper (Done by adjusting the DTI up/down on the the taper for highest reading... that should be the center.) then running the compound back and forth and checking for paralell.

When it stays zero for the whole length of the taper while moving the compound across it your compund should be set for the exact angle of the taper. Take a trim cut until you are cutting all the way around and it should then be the right taper AND concentric.

If you meant compensating for "cosine error" if you couldn't get your DTI straight up/down, all the measurements are relative so you are really just shooting for 0. 0 x cosine error = still 0.

Final step, seen elsewhere (somewhere) is bluing the taper, trying it's fit then working down the areas that rub off with an emery until the fit rubs off pretty evenly.

I was actually thinking a better way might be to make a long sharpened tool, then clamp it in your mill vise following the same angle as the jacobs taper. (In this case, simply center the cutting edge on the spindle, lay your cutting tool against the jacobs taper then lock it in the vise.) Then run the spindle and use the table feeds to cut it in situ. That way any runout in the spindle/R8 socket or R8 part of the arbor are compensated for too.

I'm not sure about that long of a cut, though... may not work. Hmm, think you could true up the R8 taper in the mill spindle that same way? Mine is like .0004 which doesn't super suck, but.... I'd try it on the outside of the spindle first.. LOL, a non-fuctional bit.

I'm not sure if the arbors are hardened.... and if so, how much. (I just checked mine.. it scratched pretty easily) Also.. the best you could do is get the arbor 100%... there would still be whatever runout is inherent in the chuck itself.

You would have to make sure you trimmed the end off as well so it didn't "bottom out" in the socket. There will be less "gap" between the JT33 and R8 ends but as long as the chuck mounts that shouldn't be a problem.

On the R8 side, you may have to trim the end that the drawbar screws in to... but I kind of doubt the clearances are close enough that it wouldn't work anyway.

Just random thoughts... probably not needed if it's under .005 out anyway, LOL. Always on the lookout for things to try though.