Refreshing a drill chuck.

[f350ca]

Tried Loctite once Stan, doesn't work, to get a seat you need to wash any oil off both surfaces to get metal to metal contact on the tapper.

[Dr Stan]

(04-30-2015, 07:15 PM)f350ca Wrote: Tried Loctite once Stan, doesn't work, to get a seat you need to wash any oil off both surfaces to get metal to metal contact on the tapper.

Good to know.  Thanks.

[PixMan]

(04-30-2015, 06:13 AM)TomG Wrote: I've chucked those up and stoned the tapered bore before. If you use a round stone and a little care, you can remove the galling without screwing up the taper.

Tom

This.

I've done it on many different applications like this over the years, works just fine.

[Highpower]

I think I'm going to use this opportunity to do some experimenting and see if I can learn a new skill, grinding my own tapers. I have a tool holder made to hold a Foredom hand piece that I can use in the lathe QCTP. I already bought a new arbor for the chuck, but I want to mount the old scarred up arbor between centers and see if I can clean it up with a grinding stone using the lathe compound. If that is successful I'll try the same with the chuck body, just to skim the surface.

If that fails, considering that I have at least 4 different chucks that all use the same taper - I have a new JT3 taper reamer on the way to keep on hand just in case. I also have visions of being able to making some special tooling adapters / extensions or whatever comes to mind.

I already have some MT reamers. Well.... ONE good one that works. The other two are Enco India crap!

Come to think of it - maybe I can use the lathe/grinder set-up to relieve and sharpen the junk reamers too.  

[TomG]

Be careful Willie. With a shallow tapered like that, a few thousandths change in the diameter makes a big change in length.

Tom

[Highpower]

Copy that Tom. The taper is .63898" per foot. And there is very little extra space at the bottom of the chuck taper anyway. This is the chuck that something let loose inside and it's doubtful that I will spend the ridiculous amount of money they want for a repair kit anyway. I just want to see if I can skim off the high spots at the top of the taper.

I haven't even gotten it apart yet other than removing the arbor. I got the tubing set up in the lathe for making the press sleeve and got one end faced off. I was working on setting up a boring bar to cut the ID when something else came up that I had to deal with. SOP around here.  Weekends are always "honey-do's", so I'm hoping I can sneak back to it on Monday.

Even if I totally screw the pooch I'll bore the chuck and press fit a sleeve, and start all over again. You can't make an omelet without breaking a few eggs right? 

[Highpower]

I got the chuck apart today but didn't find what I was expecting. No broken or cracked parts that I can see, but I did find evidence of Jacobs moving their production over to China. 

After pressing the sleeve off of the chuck body I found a tiny coiled up steel chip inside about 3/64" across. After cleaning up all the parts and inspecting them, I believe the chip came from one of the teeth on the #3 chuck jaw. I found it wedged between the jaw and it's bore in the chuck body.

               

I also found a 'peak' on the crest of the threads, on one of the half-nuts that drive the jaws. Almost like a chisel tip on a center drill. It will catch a fingernail running over the peak.

         

Most notable though are the burrs, chips, and mediocre surface finish inside the bores for the chuck jaws. I just about had to pry the jaws out of the chuck body they hang up so badly. It's going to take some time to de-burr and smooth those surfaces down with a round Arkansas stone. 

         

[stevec]

Willie, we have faith in you
 

Steve

[Highpower]

 I'm glad somebody does, because I don't....   

It may not be accurate when I'm through, but I at least hope it moves more smoothly. How close does a chuck have to run out for power tapping anywho?  

[krv3000]

hi good post