R8 true, but chuck has .005 wobble

upTheHill

Active User
Registered
Joined
Nov 12, 2012
Messages
217
my new HF mill is all cleaned and trued. I couldn't believe all the red paint splashover on the ways, and places it wasn't supposed to be.

I've pulled the R8 out, but cannot get the j33/chuck to seperate fom it.
I'm assuming that there's either crude in it, or it's just mis aligned.

any hints on seperating them?
thry are supposed to seperate right?
 
Couple things... Don't worry about wobble of the chuck body. The important thing to check is the runout of the piece it's holding. Put a small proof bar in the chuck and measure runout at a distance of about 1" from the jaws. Self-closing chucks of any sort (drill, 3 jaw lathe etc) are likely to be a little off. My drill chucks are probably within 2-3 thou and that's good enough because the drill shanks bend and flex during use anyhow. If the R8 shank is holding true, that's all you need to worry about.

For the most part, once I install a drill chuck on a taper, it never comes off again. The only exception is the drill press which has a provision in the quill to insert a wedge to drive the chuck off. Even there, I don't recall that I've ever removed the chuck in the last few years. Once a tapered chuck is mounted and if it has no provision to take it off, you'll likely do damage by trying to take it off. -It's not worth the hassle...


Ray
 
theres no runout, it cuts trueand square, so I guess I'll just let it go.
used it to make a part for my john deere yesterday, and it works great.
so I'll just leave well enough alone
 
Good. If your drill chuck has virtually no runout, cherish that thing and take good care of it. Most have some runout.

BTW: With drill chucks, you want to watch-out for bit shanks that have triangular shape (usually Silver and Demming type). I've had a couple of them twist slightly within the jaws and brother, I didn't think it would ever come loose. Had to clamp the R8 shaft with wood blocks in a vise then use a chain wrench wrapped with leather... To my delight, the chuck and R8 shaft survived the ordeal.

Also, you don't want to use a drill chuck to hold endmills. -Have never done it because I can see that bending the jaws.


theres no runout, it cuts trueand square, so I guess I'll just let it go.
used it to make a part for my john deere yesterday, and it works great.
so I'll just leave well enough alone
 
For anyone reading this later there are wedges made for removing chucks from arbors with little damage.
0859294-23.jpg

the previously mentioned method of drilling and drifting must be used in some cases like MT1/J33 etc where the jacobs taper is bigger than the other portion of the arbor.

Steve

0859294-23.jpg
 
Also, you don't want to use a drill chuck to hold endmills. -Have never done it because I can see that bending the jaws.

ok, dumb question. what should I use to hold the end mill?
 
Back
Top