Trouble replacing joint collar on warped shaft

iusedtoberich

iusedtoberich

AzB Silver Member
Silver Member
I have a job to replace a cracked joint collar. The shaft and insert under the collar are ok and will not be replaced.

I'm having lots of trouble having the cue run true at the joint collar area before I turn the old collar off. The shaft is a bit warped. I'm using a Midsize Cuesmith which means I can only get the shaft about half way through the headstock. So far I have tried:

1. Holding the shaft with the ferrule in the headstock chuck and holding the joint end with a bearing steady rest, about an inch and a half from the end of the shaft.

2. Same as #1 but sliding the shaft as far as it can go in the headstock and holding it with the chuck at that location.

3. Holding the shaft with the ferrule in the headstock chuck and holding the joint end with a live center in the existing brass threaded insert. THis way seems to work the best so far, with .008 TIR, but that is still way too much.

Is there any other way to do this job on this lathe that I am missing? Again, the root problem is the shaft is warped.

I also have a Deluxe lathe but it is not set up yet, and I was hoping not to have to put it together for this job.

I also have a metal engine lathe at work that the cue will fit through, but I don't have anything made for that lathe yet to hold the loose end of the shaft.

Can I do this job with my currently set up equipment or will i have to put the Deluxe lathe together or use the metal lathe at work?
 
Well I found a collar for my bearing steady rest that allowed me to get right to the edge of the joint collar. That got me to about .005 TIR. Then I adjusted my 4 jaw chuck on the ferrule end of the shaft but with the indicator on the joint, instead of at the chuck. THat got me to about .004 TIR.

That was good enough to turn the collar off and glue the new one on. I have to get it better though when I take my final passes once the glue is dry tomorrow.
 
Oh, I missed that. If that's the case then the shaft's insert isn't perfectly centered to begin with. What you may have to do is tweak it with shims on one side to get it to spin true, using option #2.
 
a second steadyrest

I have had this situation come up several times and if you have a second steadyrest, position it about half way between the head stock and the steadyrest at the joint. That way the shaft is secured in three places and you should be running about as true as you can get. Good luck. :smile:
 
I have a Deluxe Cuesmith and it's hard to get everything perfectly concentric all the time. There's so many places for little errors to compound. I'm slowly learning more and have given up on joints with inserts and gone to 3/8-10 with a piloted tap and the Atlas self aligning, center drilled pins. In a perfect world everything is perfectly concentric but in practice I can't always quite do it. On the Deluxe I don't like working on the shaft "big end" way out on the steady rest with the collets that don't quite get close enough to the end sometimes.

Repair work is tricky because you never know what you are getting to work on, some of the stuff is way off, warped, wobbly, etc. You might just have to get things as close as you can and explain the problem to the customer, it sounds like what he really needs is a new shaft.
 
Well, thanks everyone for their help. I finished the job tonight. I ended up going with tsp&b's suggestion. It turned out pretty good.
 

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