19mm steel lathe power shaft straighten

[PeterT]

Does anyone have leads of an outfit that could do straightening of my lathe power shaft? I'm now suspecting that might be the root of my issue. Its 1372mm long x 19mm diameter with a 5mm keyway slot up until a couple inches of the tailstock end. With both ends constrained in the HS drive socket & TS bearing & just rotating by hand with a dial, I'm measuring max run-out from headstock to tailstock at roughly 6" increments like: 0.015", 0.025", 0.048", 0.050", 0.052", 0.050", 0.045", 0.027", 0.017".

I've watched some shaft straightening vids like Keith Fenner, most use OA torch, some also cooling in a dedicated test jig. And what looks like some seasoned technique. None of which I have. I've Google'd some driveline places but not sure if they do this sort of thing, cost, lasting results etc.? I'll call Modern Tool to see if they have leads, they must see this issue too. But just wondering if anyone has some prior +/- experience with remedies?

 

[Dabbler]

- more commonly marine places do this sort of thing. transportation, etc to the west coast could be $$$. I've never done this kind of thing.

BTW is the material hardened/heat treated?

What about building a set of rollers and using a hydraulic press?

 

[PeterT]

I haven't run a file across an end but guessing its not hardened, or at least not fully hardened. I can check. The bow is generally in the same plane as the keyway slot which might be indicative that it was not stress relieved steel or not normalized after slotting & maybe part of the issue? Although, now that I have the worm gear mechanism all apart I can see thrust wear to a bracket & that may have aggravated the shaft too, hard to say.

I've watched a few vids including cold (press) straightening. My sense is there is some effort to make a setup like that - very rigid bed, rollers, retention V hooks, hydraulic bottle, welding... Pretty sure I'd be $$ way deeper than the shaft itself & none of that tooling. The localized OA torch heat straightening method Fenner shows looks significantly lighter on equipment but guessing there is some experience there.
I've seen reference to peening but wondering about surface finish (if that's more intended to be cleaned up later) & maybe like knife forging. To a bystander looks like hammering on metal, but probably some technique to get the desired result.

I'll see what Modern has to say. Faint hope clause that a current machine has a comparable bar or some leads.

 

[Dabbler]

I assumed you had a hydralic press - oops! I have one with a 30" width that could take your shaft. I don't have a set of rollers, but milling steel vee blocks will do. (my cast ones won't take the pressure). It depends on how straight is straight enough. A press will make small changes to the surface, but you could get within a couple of thou that way. Sure beats sending it to Vancouver for straightening...

Might be a good use for some of that 4" 4140 some of us purchased...

 

[Alexander]

I have straghtened lots of shafts like that including the power feed from my manual lathe using v blocks and a hydraulic press plus a dial indicator. You have nothing to loose just go for it. There is no magic in getting it straight.

 

[Dabbler]

BTW my press will take any length shaft - the 30 inches is the interval that the vee blocks are placed at...