Procedure For Boring Soft Jaws

Joe Pitz

Joe Pitz

Registered
Registered
Joined
May 7, 2015
Messages
269
Hello All,

My lathe came with a 6" chuck with no jaws.

Henry, (hvontres) sold me a set of jaws and now I would like to mount and bore them.

I checked out on the web for a procedure for boring jaws and only saw a procedure for boring jaws on a CNC turning center. Of course on a CNC turning center the turret can move horizontal and vertical.

So I am wondering how to do this on a manual lathe.

Also all the examples indicate that you must pre-load the jaws using a boring chuck jaw ring, a rather pricey tool for a one time job.

Included are some shots of the jaws.

If someone could enlighten me on the best way to bore two steps on the jaws. Is there a substitution for using a chuck jaw ring?

Could this operation be done with a boring bar? I am having trouble visualizing how to do the multiple steps?

Would you change the length of the boring bar to get the steps?

Also it appears that the position of the jaws in the chuck, (during boring) is critical to how much of a diameter that can be turned. If the jaws are not positions correctly your are limiting your diameter?


Thanks

Joe

jaws.jpg
 
Joe
Most jaws are hard enough to cause problems even for carbide and boring isnt all that accurate . The best way is to grind them.
There are a number of threads on site to give you all the information you need.
Do a search with "chuck jaws".
 
Hi Bob,

I did some searching for chuck jaw grinding out on the forum and out on the web. It appears that everyone is giving examples of correcting for bell mouth in the jaws, at most they are removing just a few thousands off of the chuck. I want to create the steps on the jaws. This would be just under .500 a step, that is a big difference in amount of material removal. Also I doubt that a grinding wheel would last that long, you would have to re-dress the wheel and or replace the wheel.

Would this same process be the best way or only way to cut the steps in the chuck jaws.

Thanks for the info on the boring ring.

Joe
 
Attack (gently) one of the jaws with a file. Does it 'skate' or dig in. If the latter you can turn them if not, you can't. In any case, if you do turn them, be aware that a lathe is not generally used as an 'interrupted cut' machine, the chuck will want to 'bounce' between the jaws, probably breaking your tool in short order. The slower you run it the less effect this will have, also, I'd hold my hand on the chuck to keep it from bouncing. You might even rig up an old boot heel (or some such) as a brake on the chuck, just to put drag on it.
Of course, if you can't file it, you can't cut it. Perhaps the jaws could be cut on a mill.
 
Joe If what you have are in fact "soft jaws" then you should not need to grind them, as they should not be hardened like the factory jaws. As for the procedure for boring them, I will defer to others more experienced than I. Good luck, JR49
 
Thanks Tom, I will check out the file approach and see what happens.

Thanks JR, Yes Henry indicated, that when he purchased them, they were soft steel jaws, not hardened.

Joe
 
Joe
Cutting steps in the jaws should be done before they are hardened. Removing that much material now could warp them.
Are the jaws hard? You should also check with Henry as he might be able to provide all the information you need.
Edit: I see from posts put up before I completed this that I just rehashed what was already said.
Please ignore.
 
You must log in or register to reply here.
Back
Top