spline chucking

[reachraghu]

Well, we are now working on a project, where we have to turn (hard turn) a shaft dia 25.4mm, lenth 270 long. One end of the shaft has a spline.

The catch is, the other end dia 17.0 should be out within 0.02mm with respect to the nominal dia of the spline.

More over, the shaft after heat treatment, has a twist and out of the centers.

Can somebody help by giving some clamping solutions?

[boxxer_boy]

Hay ya buddie just wondering have you got a very good bore in your chuck?

[reachraghu]

Hi,

My chuck has a 56mm dia thro bore.

[boxxer_boy]

i was thinking you could put a collet chuck in a four jaw chuck clock and clock up the end at the collet chuck.as for the centre being out how are you going to get it striaght? How much material has to come of? Have you thought about centreless grinding?

[reachraghu]

Hi,

We have tried making a collet with ID of the same is the female of the spline of the workpiece. But since our work is to be hard turned, the machining force exceeds the clamping force. There is no possiblity of grinding.

[boxxer_boy]

could you try make up a collor to have a mint fit in your chuck bore with a split in it so you wind up your chuck it will squash up the collor gripping the WP?

[reachraghu]

Thanks for your concern. But will this take care of the final required run out of 0.02mm? Any way I think I will give it a try

[One of Many]

Changing the initial chucking won't improve on this if it already checks out within .02mm before HT.

I seriously doubt you will get rid of the runout if the part requires a heat treat process after it is turned. The 2 ends are very unlikely to maintain the same center if it distorts at all.

If the part checks good before it is HT'd, then the HT should be done first, if at all possible, then straighten if need be, then turn or grind the one end true to the spline. I think this comes down to the process sequence and methods you have chosen.

You might place this in a heat treating fixture to stablize the part to minimize warpage, but unlikely to eliminate it within .02mm. Hanging them from one end helps. Although, if these are quenched to harden, the chances of warping are much greater.

DC