Ball Turner #3

[rdean]

I have a project coming up that requires me doing some ball turning for the handle ends.

I have made two different ball turners over the years and was not satisfied with either one. The first I made was mounted on the carriage and that one required me to remove the cross slide entirely to use it. The second was mounted in the quick change tool post but it was not very stable and hard to control.

Both of these designs had the same problems as the swivel handle was always in the wrong place or was hitting something. If you made the handle short enough to miss all the obstacles then you have little control over the cut. Also the ball size was limited by how much room there was between the turner base and the material or chuck. Neither was precision adjustable and setup was a job in itself. I searched through many designs and this is what I came up with and it is not original but does have some personal tweaks.

I have a boring head I use on the mill with an R8 shank so I would start with that but I still wanted it available to just put back in the mill for a job there.






The parts and the first cutter I made from a ½” drill bit. It worked fine on aluminum but was not very good on steel turning.






I used a carbide insert for the second design and the result on the steel turning. I have since modified the end clamp to more closely follow the insert shape and may modify the shank as well.

I now have a ball turner that is easy to control, is very accurate, greater capacity, and is installed or removed in a couple of seconds.

Thanks for looking
Ray

 

[jeff_g1137]

Hi
Nice
does it spin on the r8 tapper.
jeff

 

[Gary Gill]

Interesting method. Thanks for sharing.

 

[rdean]

Well the base does have a taper on the end but not the R8 size. I didn't want it lock in it just rides on the outside edge. This shows fitting the hole for the boring bar.



The handle end is a close fit for the R8 taper end and the backlash is a about 0.002 so it is good and solid.

Ray

 

[FOMOGO]

Looks like a good solution. Will have to put it on the list. Thanks for sharing. Mike

 

[Uglydog]

If I understand correctly the bolt is acting as a draw bar and the lever facilitates rotation.
The ground surfaces of the R8 are working as bearing surfaces.
Is that a correct understanding?
If so are you getting any binding of the taper on the R8?
Is the tool post shop made?
Did you cut the taper in a 4jaw and turn it?

Thanks for the post!
Daryl
MN

 

[rdean]

Yes you are correct the bolt is the draw bar with no means of adjustment for backlash. It took several fittings of the end cap to get it just right where it was smooth turning and not too loose. I wish I could hand it to you and say just feel that fit and movement.
The tool post came with the lathe but the holder was made from a steel chunk I cut and machined.






Thanks to all
Ray

 

[Uglydog]

Interesting!
Is the taper an exact match for the R8?
I'm super curious about how it slides/slips without locking up or tightening as it would in a mill quill.

Daryl
MN

 

[rdean]

I recently had made some R8 tapers for another project and I even started to cut this one with that taper but I realized that it might lock up so I increased the taper so it only touches at the far outer edge. This could even had been bored straight with no taper.

Well the base does have a taper on the end but not the R8 size. I didn't want it lock in it just rides on the outside edge.

 

[f350ca]

Great idea Ray ! I've been thinking of building one but hesitated at buying a boring head just for it.
Would an inside tapered sleeve to go over shank act as a better bearing or am I over engineering again.
Thanks for posting
Greg