[rlivergood]

I have a part that needs to go into production to be machined and I have, to my thinking, a nightmare of a workholding situation. I attached a bit of a blueprint for reference, but I need to use a 0.310 diameter hole with flats that are only open to 0.205 to hold my parts. I tried using a 1/2" head diameter 5c collet turned and machined to size, but the head sides end up so thin that they just twist and break. Just to get the sample out, I made a mandrel to size and drilled and tapped the end so that the parts could be machine that way, but that isn't going to cut it when it comes time for production. Also, of the 7 turning centers that I have, only 2 of them have a tailstock, so I can't rely on that for workholding. My idea was that we shouldn't be doing these parts, but that fell on deaf ears. So, any thoughts on how to possibly hold this would be appreciated.

[Jim Dawson]

The only thing I can think of is an expanding mandrel. Exactly how you would tie that into your collet closer would require a bit of thought.

In my shop I would think seriously about running these in the VMC rather than the lathe. But I agree, if this came into my shop I think it would be a no-bid.

[handlewanker]

Volume....it all depends on the volume........a part that makes 10 cents on the dollar is only worth it if the volume is high.

[deadlykitten]

hy, if that gear will work on a shaft 0.31 with flats 0.205, then is possible to machine it, clamping it just like it would be in the assamble, or similar

small parts require a gentle approach, you can't rush them, or they will fly off

inner shaft will work like a go gauge, so not only that it has to slide smooth before machining, but also after

soft shaft + heavy specs : not so good
heat treat, grinded, responsable specs : better

i could draw fast some clamping methods, but i need to know how the part looks before and after machining, or the stage that you wish to do

there are some normal geometrical conditions in your drawing, that has to be addresed in a certain order, or somehow adjusted among the way / kindly