3 Jaw Drill Style Chuck Honed Jaws?

[zrwhat]

We have reverse engineered a Chuck for a medical Instrument and we are not getting the same clamping pressure as the original. The one question we have is if the Jaws need to be Honed/Lapped in to make sure they are applying even pressure to the object you are clamping? When you buy replacement Jaws from say Jacobs you are instructed to change out all three jaws even if you only have damage to a single jaw. Thanks for the help!

 

[cloa]

Of course. But its probably more the careful alignment and co-actuation that is needed.

 

[dhengr]

Zrwhat:
When replacing the three jaws in a chuck, I can imagine the sum of any tolerances causing some minor misalignment of the three jaws; the more so if there is wear and/or you try to replace only one jaw. Why not try this: replace all three jaws, then snug them up around a cylindrical hone of some sort, and run the machine for a while; snug the jaws a bit more and repeat. This should shape the inside surface of the jaws to match the cylinder they are holding. Maybe you hold the entire chuck stationary and turn the cylindrical hone. Holding the entire chuck in the snugged position might be the tricky part.

 

[mfgenggear]

zrwhat

the quality of material & accuracy of manufacturing will affect how the jaws grip equally.
in addition for the jaw to grip equally as dhengr has stated, a final light machining or hone to true up
the id gripping dia to true them up is helpful. & if possible.
in lathes a ring is inserted into the 3 jaw chuck. it is then trued up by machining the id of the jaws.

what is the repeatability of all the attributes. do a sample inspection of the competitors & your parts.

HTH
mfgenggear