Which ball turner?

Hi all.
looking to get a ball turning attachment for my Sabel Lathe.
Candidates seem to be:

The circular style Myford one commonly on eBay.
The Hemingway kit.
Make a home brew one for a boring bar that mounts on the cross slide.

interested to know others experiences with this accessory and any thoughts on the above options.
cheers, Jim

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

Hi Howard.
I did look at the Repton when doing my research but didn’t include it in my list as it doesn’t appear to be available any longer.
If you know any different I’d be interested to know of a current supplier.
Cheers, Jim

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.

Hi Chris.
Many of eBay ones appear to be of the Bedair design but aimed at Myfords.
I don’t see any centre height adjustment in them but may be missing something.
Regards, Jim

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

Hi Jim

Boring Bar head on a bushed shaft mounted horizontaly on the toolpost with a round nose high speed tool steel with the cutting edge on the vertical centre line will work fine and will cut on the right or left swing.

Use the tool upside down with the flat side facing downwards.

A 400 mm lever on the piviot shaft will give good control and finish with minimum effort.

Eric

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

Thanks Eric and Clive.
I was looking at the boring bar in a bush and have sourced some

2” bar with this in mind but hesitated at buying another (parallel shank) boring head.

Eric, maybe you should sell me your Hemingway kit?
I too have an R8 mill so I can imagine the size of the tool carrier.
Jim

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

Did you guys with the Bedair or variants simply download his drawings and get cracking?

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 used the Bedair style as the basis for mine but included a ball race in the design. It works ok but I think this is a better idea:

Turnado

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

regards Martin

This is my boring head on R8 shank version set-up in the Dickson T2 tool post on the Smart & Brown 1024 (10" swing) lathe. Made from materials I had in stock.

As you can see anything smaller runs out of room to mount in the tool post or directly on the top slide. If you are going to have to pull the topside off to mount directly on the cross slide its a lot of extra work compared too a Bedair type for little objective return. Especially if you can figure out a calibration system for the Bedair version.

Need to use a T2T type carrier with the deeper slot as that gives enough room to pull the boring head back alongside the slot. Afterthought in my case so the mounting tongue isn't quite the right size and position for simple push into place mounting. I need a thin shim underneath and should use a spacer at the back. One day I'll screw a bit on the back.

Few details are a bit rough but it works.

If making one with its own dedicated plain shaft then a basic block about half the tool carrier length will be fine.

Adjustable stops to control the swing are advisable. But something of a pest to make attractive. I just knocked the ruff edges off and called it good!

I wonder where I hid that Hemingway kit last time I tidied up (sort of) the shop.

Clive

Edited By Clive Foster on 29/10/2020 12:11:14

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

Like Jason I made mine to suit the machines centre height and also use a triangular tip. I never did get around to adding a scale. For a full ball I just push the slide/tip up to the side of the work. Most use mine gets is adding large radius to the heads of bolts on old motorcycle projects. Run the lathe fast for good results.

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 have the Myford type I lent a friend a very poorly home made one which he over tasked so he was kind enough to replace the broken one, Ive found it as done all I required of it.

H

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