Thanks to an unexpected gift, I was able to splash out on a Repton, from Chronos.

It was, in my book, expensive but nicely made and finished. Took a little getting used to, (I ended up making a fixture to centre it, and using it, seemingly, other than in accord with the instructions. )

But the proof of the pudding is that it works well.

Howard

A friend bought a ball turner some time ago, I can't remember the make but it was not cheap. He returned it for a refund as it was very poorly made. I then made myself and the friend one loosely based on the design by the late Steve Bedair. Cost nothing as made from stock/scrap. Works very well but really needs the work held in a collet to allow the attachment to get close and sometimes a three jaw would get in the way. The sliding part to alter radius on some designs just slides in a plain square edged slot I refined this and dovetailed the slider.

Jim,

Like Chris, above, I made one loosely based on the one on Steve Bedair's site. Again, like Chris, I incorporated a few "improvements", which I've shown in this video:

Link to video

The square slot is my only slight criticism and if I were to make one again, I'd certainly try to incorporate a dovetail of some sort for more secure tool alignment and I think I'd include some sort of scale to aid setting radius size. One for the back burner.

John

Getting the tool profile right is the really important thing with ball turners provided the mechanics aren't too crude. One day I shall experiment with a triangular insert, as used by Steve Bedair, on mine.

I obtained a Hemingway kit but never got round to making it. Still on the shelf so I guess I should sell it!

Made the vertical swing, up'n over, boring head type instead. Works well but its a cumbersome unit on a smaller lathe as it inevitably comes out quite long. Especially as I made mine with an R8 taper carrier so as to diectly share the boring head I use on my Bridgeport.

Objectively I should have got another head and made a shorter carrier. Even with a shorter carrier mount you will run a out of room on anything under 9" swing. On my S&B 1024 and P&W 12 x 30 I mount it in the QC toolpost but its a stretch on the S&B. Calibrated adjustment is a big advantage.

Given how little I actually use it I'm inclined to think that the simple Steve Bedair design is the most appropriate for home shop types. Height adjustment isn't needed as you amke it to fit your lathe. I'd put a bit of creativity into arranging calibration tho'. Perhaps use one of the lunatic cheap digital tyre tread depth gauges and a range extending spacer to measure the actual setting.

Clive

Edited By Clive Foster on 29/10/2020 09:45:26

Edited By Clive Foster on 29/10/2020 09:46:56

I made a Bedair one that works OK, better with the 5C chuck I now have as you don't need so much stock sticking out to avoid hitting a chuck. I just made it to suit the my ctr height

Edited By JasonB on 29/10/2020 10:06:44

Jim,

That's more or less what I did, although I redrew them with metric dimensions to suit my in-house unit system. Unfortunately I've lost the drawings in a hard drive crash so can't offer them to you.

John

I built the Hemmingway version and I'm very pleased with it.

regards Martin

I bought the Hemingway kit just after getting the mill, and made a mess of everything I did.

This repurposed the shaft and shaft holder, plus a couple of other bits including the tool:

The head and slide are from 60mm bar, the slot is 10mm wide. Shaft rotates on cheap bearings, and is screwed and loctited to the head.

It's only ever likely to be used for decorative balls(gear knobs, handles etc) so I saw no need to complicate it with an adjuster mechanism

Interesting! I had wondered about mounting a Boring Head in the toolpost so that it could be used to turn radii.

There is the proof that it does work!

Howard

I was going to do that, but even the generic 50mm boring head takes up a huge amount of space

Hi Clive

I can now see how a smaller lathe with a boring head fo a ball turner is a bit of shoe horn job.

A round piece of tool steel does a good job and cuts left and right

This is the MEW Boring Bar set up as a Ball Turner. Has turned out a lot of stainless knobs to replace plastic ones.

Eric

Hi Jim,

If you go to the boring head style make sure you look at **LINK**

He shows the best idea for a cutting tool, using a circular insert ceramic tool tip. No grinding of difficult angles for the cutting tool, a brilliant system! —— I see I am too late as you have made your decision, but any others either using or contemplating the boring head style should take time out to look at this.

Regards,

Nimble Neil