Boring head Ball/Radius turner

[RodW]

There seems to be heaps of threads on ball turners on the forum but not much said about using a boring head to do this. So here is one set up to fit on a BXA tool post.









When I bought my boring head, I bought an additional straight shank mounting flange for it. It had a 20mm diameter shaft. I bought a pair of 42mm x 20mm x 12mm bearings which only cost $5.50 each. The body is made of aluminium (from 50mm x 100mm flat bar) and the handle is 12mm steel. I found some plans online but I had to redo them as they were for a CXA tool post.

I improvised with the height adjustment  over the weekend for now and used a washer sandwiched between two nuts and I was able to centre it OK. You only need to do this once and is pretty easy. It is just a matter of adjusting the height until the tool touches the top and bottom of a piece of round stock in the chuck.

So drill and tap the end of some bar stock, part off the piece so it is the same length as the diameter and go for it!



Just wind the tool in gently and take your time with small cuts.








Umm... loosen the ball before you polish it as it was very hard to get a grip to unthread it from the mandrel (just use any old bolt the right thread)



Beautiful!

To polish it, with the lathe running at 500 rpm, I started with 240 grit sandpaper  and moved up to 400 wet and dry kept wet with some kerosene. Then moved up to 600, 800 and 1000 grit (with kero) before the final polish with Autosol metal polish which you should be able to get from a car accessory store. Looks like chrome!



I hvae yet to try a concave radius but it should still work just by turning the cutter round the other (I mean right) way.

Oh and another tip I learnt somewhere, maybe even on this forum. When tapping a thread in a lathe or mill, remove the anvil from a self punching centre punch and use it to hold the tap centred.


This really works  treat and the tool can be returned to normal (but as I had 2, I cut a ring around one with the lathe) so I know which one is what.

[Arbalist]

Nice job on the ball turner! 

For tapping in the Lathe or on the mill I made a couple of these, same idea as your punch.



The middle one is for small taps that have a point on the end. The bottom one was shop bought but was so badly made I had to make a new point for it as the fit was very sloppy.

[RodW]

Nice job on the ball turner! 

For tapping in the Lathe or on the mill I made a couple of these, same idea as your punch.

The middle one is for small taps that have a point on the end. The bottom one was shop bought but was so badly made I had to make a new point for it as the fit was very sloppy.

Great idea thanks. I like the countersunk one for the pointed taps. I have got a couple of nice tapping T handles that are centre drilled at the back end but if I do get into trouble one day, I will copy your idea.

[Arbalist]

The commercial one on the bottom was double ended, point one end and countersunk the other so should work with anything!

[Brass_Machine]

I like your ball turner. Very ingenious way of doing it.

Eric

[John Stevenson]

Used one of these ball turners made from a boring head for years.
Advantages are not limited to fitting one lathe, quick to use, just like swapping a tool and calibrated to boot.

It's always amazed me that so many of the Bedair type have been made given the pain of setting them up and how many balls do you actually do ? At least with this setup you still have a boring tool.

And if you really want to push the boat out fit the same boring head to the tailstock, fit a hollow centre like the tap centre above to the tailstock end and chuck. Then using two ball bearings as 'centres' you have a very cheap taper turning attachment that will fit any lathe whether they made a genuine one or not that can do longer or steeper tapers than a dedicated one.



Beats off setting a tailstock you spent 8 years getting to turn true.

[DaveH]

Beats off setting a tailstock you spent 8 years getting to turn true.

That is so true 
 
DaveH

[awemawson]

I made a ball turner using a boring head quite a while ago - just dug it out, 2004 according to my stamp on it, so ten years ago 

Mounted on a Dixon T2 quick change holder with a custom made 90 degree worm & wheel. I seem to remember the holder started life as  a N0 2 Morse socket, which I softened, and parallel bored to take the boring head spindle. Can't remember if I re-hardened it 

[RodW]

Guys, thanks for the feedback.

John, I know about the offset application of a boring head,  just I have not needed to do that yet. My lathe and mill both take a MT3 taper, I must get a couple of set screws so I can set the taper engagement depth when I move stuff to the lathe.

Awemawson,  you have given me an idea, I should date stamp my accessories. I also have a logo stamp I got made to brand a particular part I make but when I  polish stuff like the balls shown,  I just can't bring myself to use it! I put quite a long handle on this tool (12" or so) to give me some control of it, I think I could have made it shorter but so far, I don't see the need to add a gear train to a simple tool.

Rod

[awemawson]

Rod,

The idea of the 90 degree gearing was to allow reasonably accurate 'partial arcs' to be turned, both concave and convex. The handle variant will do the same if you add stops to it.

[Arbalist]

It's always amazed me that so many of the Bedair type have been made given the pain of setting them up.

I made my Bedair style ball turner from stock I had to hand including the bearing. I don't have a boring head but can see the advantage of this type. I may well make one if I buy a boring head. I think more folks would make this type if their were more build logs of them available. I should add that I have a four way tool post but don't see that as a problem. Do you have to use bearing races or could you use a plain bearing and what's the best way of limiting end float? Any links to plans/drawings or build logs?

[velocette]

Hi
A boring head for ball turning I find one of the most satisfying tools to use in the workshop lots of feel a real hands on tool.
Personal preference for cutting tool is a round nosed HSS tool with 4 - 5 deg top rake,  6 - 7 deg front rake  and used upside down of course.
""Do you have to use bearing races or could you use a plain bearing and what's the best way of limiting end float? Any links to plans/drawings or build logs?""
To reply to "Arbalist"
A plain  Bronze bearing with a close fit  .001" per Inch diameter is a guide use a thrust washer on the front and rear face, keep lubricated with light oil.
The force from cutting will take up all clearance - - end float.
Eric


 

[redshift]

Can someone pleases explain to me the geometry of the cutter. For the life of me I cant see how this can work, it obviously does,
It  just seems all wrong with the cutter operating vertically as the cutting edge would be 90 degrees out.
Regards
Dave

[RodW]

Can someone pleases explain to me the geometry of the cutter. For the life of me I cant see how this can work, it obviously does,
It  just seems all wrong with the cutter operating vertically as the cutting edge would be 90 degrees out.
Regards
Dave

Dave, I put the tool in the opposite way to what you would use for boring. On one cut it is using the back of the tool but it works. Some people have made up a custom tool with a better profiled insert tip for the job in hand. I might do that one day.

I thought about using bushes but the bearings were cheap at only $10 the pair and easy to source.

[Chuck in E. TN]

Rod, I have also used my boring head for turning tapers. I turned ball ends on some 1/2" drill rod, unhardened, mounted the stock between them, and set the taper with the boring head. Made a couple of MT2 tapers to test. Works great.
Chuck

[RodW]

Here is a video in action aftr someone asked me nicely. Now who would that have been Chuck?

[Chuck in E. TN]

Yeah, it was me, Rod. Great video! Thanks.
Chuck

[velocette]

Hi can I add to this earlier posting
""Personal preference for cutting tool is a round nosed HSS tool with 4 - 5 deg top rake,  6 - 7 deg front rake  and used upside down of course.""
This will produce a very good finish on Stainless steel aluminum an mild steel. Take fairly light cuts and use cutting fluid.
I remove the toolpost and bolt the Ball Turner - Boring Head in is place.
Just an idea that this may help for the smaller lathes.
The Housing was bored with the boring head mounted in the chuck so it is on the Centre Line.
A couple of photos show the boring head built from plans in "Model Engineers Workshop".

Eric