Parts need turning

**ams** · 12-01-2014

Hi

I have 5 parts I need turned. There are 2 cylinders which are pprox. 440mm long and 25mm in diameter. The other 3 parts are approx. 450mm long and 6.7mm diameter. There is very important detailing and threading to be done on 2 of the parts.

Please let me know if you could take on the job. I will provide engineering drawings and 3D CAD files. I could also supply the steel round bar if neccessary.

Thanks

**Jonathan** · 12-01-2014

'450mm long and 6.7mm diameter'

That one is going to be challenging if the diameter needs to be remotely accurate, as the length to diameter ratio is very high.

**irving2008** · 12-01-2014

Will definitely need a good quality toolholder mounted travelling steady to get any degree of diametrical accuracy...

**Lee Roberts** · 12-01-2014

Originally Posted by ams

The other 3 parts are approx. 450mm long and 6.7mm diameter.

Could you not go to 8mm or down to 6mm for these parts as per the other posts above this one?

.Me

**EddyCurrent** · 12-01-2014

1/4" might also be an alternative if you're thinking about using standard stock

**Lee Roberts** · 12-01-2014

Originally Posted by EddyCurrent

1/4" might also be an alternative if you're thinking about using standard stock

Doh of course!

**m_c** · 13-01-2014

Swiss/sliding head lathe, or a roller box would take care of the 6.7mm.

**AdCNC** · 14-01-2014

Originally Posted by m_c

Swiss/sliding head lathe, or a roller box would take care of the 6.7mm.

TBH i think a Swiss/sliding head is the only way to go for this sort of job if accuracy is important.

**corkcnc** · 15-01-2014

Sliding head is all well and good for the OD but I'd agree with RH that a gun drill is needed for the ID for any bit of accuracy. If you started off with a tube with the ID already close enough to the required finished dims then the bore of the tube might keep you in line (with a new drill - symmetrical point angle and both lips even) but not for tight tolerances. You would need a long travel to accomodate the long drill or a gun drill at starting point and the material held either with the rear in the chuck and front on a fixed steady or else the front of the job in the chuck and the rear in a custom collet at the "back" of the chuck, i.e. left side of the machine.
It's quite specialised but for those with the correct tooling it shouldn't be overly complicated. Cylindrical grinding as mentioned previously would be the most cost effective method of achieving the final ODs on the smaller shafts.
Best of luck with it.
Noel.

(Edit: Looks like Irving said what I was trying to say about 2 minutes ago :) )

**ams** · 13-01-2014

I cant change any dimensions unfortunately because these parts fit into the entire assembly, I'm sure there's room for error but it would be small and difficult for me to estimate. Anyone willing to take a crack at this?