In total shock over my Shars 3-Jaw Chuck

[RandyWilson]

He's holding the phone with one hand while spinning the chuck with the other.

 

[David S]

So often we hear the things that are wrong with Chinese products, it is refreshing to hear stories like this where the chuck is so good you may not need collets.

When I was working in consumer appliances and tools we had suppliers in China and our own plant as well. I can attest that they are absolutely capable of making products to whatever quality level you wish. On some of my visits there I saw suppliers with dirt floors producing crap and some with clean rooms producing products of the highest quality.

Back a number of years ago a book was published "Poorly made in China". I could relate to most of the examples that were mentioned in the book. Our purchasing department would relentlessly demand lower pricing, but eventually in order for them to survive they would start cutting corners. And yes there were instances where we did it to ourselves.

Glad to hear that this chuck was indeed good value.

David

 

[darkzero]

Congrats Grizzly! I have to use darkzero’s “Tap-Tru” method to get anything close to .0005”.

Which leads me to a question that has been haunting me and is sort of on topic. Regarding taking a couple thousandths off the register and then tapping on the chuck to center the work, why have a register at all? I understand having an undersized register for a Set-Tru type chuck with adjusting screws that bear on the register, but for “tap tru”, what purpose does a register serve? A flat faced adapter plate sure would be easier to make. So, should I patent the heretofore unheard of flat faced chuck adapter plate or just pay better attention in class?

Tom

Note to Mods: If you think this is OT, let me know and I’ll delete it. Or you can.

I believe the register is there is to prevent the check from getting knocked out of true. Like on a Set-Tru chuck, the boss on the adapter is slightly smaller than the register on the chuck to allow adjustability but the adjustment screws are there not only for adjustment but also to keep radial alignment. On inexpensive adjustable chucks, sometimes you'll see very small adjustment screws, but on my Bison Set-Trus the adjustment screw are much larger in diameter.

And even with the Tap-Tru method, the boss on the adapter can serve as a "prealignment". Normally probably not too often would you remove the adapter from chuck but when you do at least it'll get you somewhat close to alignment before tapping true. After all, you should take apart the chuck & give it a cleaning/regrease periodically. Yeah, it probably serves no valuable purpose for a Tap-Tru set up but still I would want it there.

 

[higgite]

And even with the Tap-Tru method, the boss on the adapter can serve as a "prealignment". Normally probably not too often would you remove the adapter from chuck but when you do at least it'll get you somewhat close to alignment before tapping true. After all, you should take apart the chuck & give it a cleaning/regrease periodically. Yeah, it probably serves no valuable purpose for a Tap-Tru set up but still I would want it there.

Yeah, ballpark pre-alignment is the one benefit I can see for an undersized “Tap-Tru” register. It will help keep from starting the tap-tru process with the chuck so far out of alignment that tapping it into alignment would skew the mounting bolts/screws excessively. I’m calling that a plus. Thanks for spoiling my patented flat faced adapter plate. Back to the drawing board.

Tom

 

[Bob Korves]

There is nothing that would prevent us from making an oversized back plate that recessed the entire width of the chuck within a shallow counterbore, with radial adjustment screws pointing inward.

 

[darkzero]

Yeah, ballpark pre-alignment is the one benefit I can see for an undersized “Tap-Tru” register. It will help keep from starting the tap-tru process with the chuck so far out of alignment that tapping it into alignment would skew the mounting bolts/screws excessively. I’m calling that a plus. Thanks for spoiling my patented flat faced adapter plate. Back to the drawing board.

Tom

Haha, sorry about that Tom! I'll promise to keep my mouth shut on you next patent idea!

 

[darkzero]

There is nothing that would prevent us from making an oversized back plate that recessed the entire width of the chuck within a shallow counterbore, with radial adjustment screws pointing inward.

And another haha! Now that's thinking outside the box, or should I say outside the chuck! I wonder if anyone has ever tried it?

 

[mikey]

There is nothing that would prevent us from making an oversized back plate that recessed the entire width of the chuck within a shallow counterbore, with radial adjustment screws pointing inward.

If someone ever does this, we'll label it a "Korves-Tru" chuck because we'll always remember that we saw it here first!

"... thinking outside the chuck!"

 

[higgite]

I've got it! To heck with my flat faced adapter or Bob's "Korves-Tru" chuck back plate! I'm going to mount my chuck with a big coil spring between chuck and spindle, sort of like those novelty eyeball glasses, and just let it center itself. Sometimes the simplest solution are the best. "Hello, patent office?"

Tom

 

[Bob Korves]

If someone ever does this, we'll label it a "Korves-Tru" chuck because we'll always remember that we saw it here first!

"... thinking outside the chuck!"

Aw, shucks... I cannot believe that no one has thought of this before, though I have not seen any reference to anything like it. I do not see much down side to the idea. The extra diameter width near the back of the chuck would be in an area that is not normally in the way of anything. It would also be possible to turn down the rear corner of the chuck on some styles of chucks to allow it to be smaller in overall O.D., basically re-inventing the set-tru idea. It would require a fairly large chunk of metal to make such a thing, but, to me, that is not a deal breaker.

My main issue with the idea is the entire set-tru concept. I do not particularly see it as a real gain, and do see it as more possibilities for looseness and loss of rigidity. We still need to dial in the work, and could have done so with a four jaw chuck in the first place. It might be an advantage if doing quantities of parts with one diameter to chuck that do not need to be dead nuts accurate. Scrolls being what they are, any change in diameter probably will require dialing the chuck in again. I really think that Stefan Gotteswinter's tap-tru (or bump-tru) idea is simpler and achieves the same result with a lot less effort and material.

Edit: If anyone wants to take this on, I will only ask for a small royalty per unit...