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Keyless Drill Chuck Runout ~ 0.0015", True or False

EPAIII

Diamond
Joined
Nov 23, 2003
Location
Beaumont, TX, USA
I just watched a Haas Automation video about tool holding.

YouTube

Now, almost everything on his table, and there were a bunch there, is probably beyond my reach unless I suddenly get a rich uncle with a habit of walking on banana peels, but...

He talked about keyless drill chucks and said that the advantage that they have is better runout. He did not mutter a single word about ease of use or no lost keys or better grip or anything except better runout: according to him, that is the reason for having a keyless chuck. Specifically he said that they (all keyless chucks?) have a runout of 0.0015" or less. He also did not mention ball bearing chucks vs. non ball bearing ones. The ones he had were apparently Albrechts which can be somewhat expensive but not the most expensive that I have seen. Now, putting aside the quality level of construction, the design differences that I see between keyed and keyless chucks are two: first, the obvious key vs. no key. And second, the keyless chucks will have a finer thread on the barrel because they are to be tightened by hand, not with the mechanical advantage of a key.

So, if a keyed chuck were made to the same quality level as a keyless, then just why would it not be just as good with respect to runout? I have seen keyed chucks that are quite a bit more expensive than many keyless ones. Is it just that no one bothers to make such a high quality keyed chuck in spite of the prices? Or is there some other difference that I am missing that provides this increase in accuracy (less runout)?

And can I expect that a lower priced keyless chuck would also have this mysterious quality advantage? I have some hand powered drills (egg beater style) with keyless chucks. I have never bothered to check their runout, but I highly doubt that it is all that great. Stated another way, just where can I expect to start finding this increase in quality in keyless chucks.
 
If stated as you describe (I've not watched the video) then it's too broad a statement. The best keyless chucks, if made correctly, will have low runnout, but I've seen worse, as have these guys: Albrecht Chuck runout

It also depends on how well they were mounted on their arbors, if not integral.

Keyed chuck, because the key works from one side, in theory induces an angular or offsetting load on the outer sleeve, allowing the three jaws to displace a little. Again, better made key chucks should have less effect, and since some good "keyless" chucks do include an option to use a key or wrench to give further tightening to the bit this shows the effect isn't overwhelming.

Best thing about key or wrench tightened chucks is reduced likelihood of inertia or reversed load causing loosening of the bit or tap. One should be cautious about taking advantage of this, but on a manual machine like a knee mill it's done lots of times.
 
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''Keyless Drill Chuck Runout ~ 0.0015", True or False ''

They say seeing is believing, ...and if I saw it I'd be getting my eyes tested.
 
the question is also how (where) the tir is measured. (over here the standard is 10x diameter from the jaws.) without specifying that the values are meaningless.

btw, i have a keyed chuck with zero runout. its a cheap chinese one. i sent back two röhm "superprecision" keyless chucks with 0.07 and 0.09 mm runout.
 
The diameter of a hole saw creates so much tichtening tork on the chuck that it ruins the thrust bearing
Impossible to open the chuck normally Thats when the pipe wrench comes in
The hex shank makes it impossible to slip also
I had it on several occasions that the hex shank splitt lenghtwise to the hole
Peter
 
Yeah...keyless chucks and hole saws don't seem to do well together.

As for runout...I just happened to browse on Ebay for a keyless chuck and Quality Machine Tools is offering a chuck they claim has .00078" or less runout.

As for me, I'm not too concerned with runout. Or rather, if I am concerned with runout, I'm not gonna expect it out of a keyless chuck. If I need under .002" it's collet time.
 
To be really honest, I never use drill chucks on a cnc machine.
ER32 collets are the way to go IMO.
One reason is you can slide the drill up as high as possible for maximum rigidity.
Drill chucks>>>> for drill presses.

:argue:
 
Yeah...keyless chucks and hole saws don't seem to do well together.

As for runout...I just happened to browse on Ebay for a keyless chuck and Quality Machine Tools is offering a chuck they claim has .00078" or less runout.

As for me, I'm not too concerned with runout. Or rather, if I am concerned with runout, I'm not gonna expect it out of a keyless chuck. If I need under .002" it's collet time.

would you have a link? i cant find that seller. there is one with 0.0004 tir listed, btw. $500.
 
To be really honest, I never use drill chucks on a cnc machine.
ER32 collets are the way to go IMO.
One reason is you can slide the drill up as high as possible for maximum rigidity.
Drill chucks>>>> for drill presses.

:argue:

I've done it plenty of times, especially for smaller drills. It's picking and choosing where you use it, and I don't go over 3/8" drill size (usually 1/4" and smaller).

Just a matter of quality chucks properly mounted on good arbors, very rarely have any issues. But I never try tapping with chucks, just dedicated holders.
 








 
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