# Boring Head ball turner



## 8ntsane (Apr 14, 2011)

Hi Guys

I put together a ball turner with common stuff that most all of us allready have in the tool box.
I allready have a 2 inch and a 3 inch boring head that I commonly use on the mill, either will work. Both of mine are just the cheapo import variety with the screw on arbours, either R-8 or M/T. I bought a M/T arbour from the local Busy -Bee for I think was $16.00 . I mounted it to the boring head, then just chucked up in the 4-jaw , and machined it down to 3/4 inch. The AXA QCTP sets come with a toolholder for 5/8 boring bars, and I just removed the sleeve, and the ID is 3/4.

The only Parts I had to make was the Handle, the piece to bolt on to the modded M/T shaft, and a stub to hold the cutting insert.. Only three parts in total, as the boring head, toolpost holder, was allready in the tool collection anyway.

This type of ball turner will get up really close to the chuck, and will also make concave/convex cuts to the ends of shafts.

The tool was allready sitting there anyway, and all I had to purchase was a 16 dollar arbour, and a few bits from the scrap bin, and I have a use full tool.. Whipped it all together in about 2-hrs time. Quick n dirty way to get making balls.

So, for the guys that dont care to make the hole tool, and just want to do the min, this is about the fastest way, Ive found.
Paul











Thanks for looking


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## Starlight Tools (Apr 14, 2011)

Good work, looks like it will do the job nicely, and a whole lot lighter than the holdridge I picked up.

When I get a QCTP holder for a boring bar setup, that is on my plans as well. figure it will work better for the small balls and leave the holdridge for the really big ones.

Walter


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## 8ntsane (Apr 14, 2011)

Walter

You got a Holdridge
Man those are ones to have, I thought about making one, I seen plans over on PM. Id say that must be the best ball/radius tool you could ever own. They are sweet.

Paul


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## Starlight Tools (Apr 14, 2011)

Paul

In a moment of Ebay insanity I clicked the winning bid on a Holdridge 8D Radii Cutter. Mind you by the time I got the freight bill and then when the Broker got finished with me, I sure flet like I had been probed in all the wrong spots.

http://hobby-machinist.com/index.php?topic=1308.0

Here is the thread where I showed it off in true tool gloat. It was a smidge too high to fit my lathe as is, and Holdridge was very generous to offer to modify the frame to fit my lathe for nothingas long as I picked up the freight both ways. I decided to take on the challenge and do it myself and it worked out really good.

According to the Holdridge website, they have come out with a new version and it is very similar to what you made in an over the top style, with a 40:1 Worm Gear drive.

Toys, Toys Toys.

Walter


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## 8ntsane (Apr 14, 2011)

Walter

Looks like you scored big time on the Holdridge.
That puppy will do so much more than a simple ball turner would ever do. The Holdridge may be big and heavy, but that tool will do some serious radius work! Hey, what you machined off the bottom of your Holdridge, IMO would not hurt the strength of the base at all, even if you where taking heavy cuts with it.
That is a tool thats meant to be worked.
OK, I,ll stop droolin now. Nice score.

Paul


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## Starlight Tools (Apr 14, 2011)

Paul I contacted Ellery Holdridge from the factory and this is his reply

"If the center height of the Radii-Cutter is too high, there are two options:

1) Mill .150" off of the bottom of the Radii-Cutter frame, this is the maximum amount you can remove without affecting the integrity of the tool. You can send the frame to us and we would be happy to do this for you at no charge.

2) Make a block to mount the Radii-Cutter on, the top of which is at the height you require. I would actually prefer that you consider this option, as I would rather not change the Radii-Cutter Frame. You can mount this block where the compound sits on your cross-slide (which would require removal of the compound), or you can mount the block somewhere else on the cross-slide; sometimes putting in on the back side of the cross slide is handy. This requires drilling and tapping a few holes in your cross-slide to mount the block. It's a bit of a pain in the neck to do, but once you've done it, it works quite well.

Let me know how I can be of help.


Ellery Holdridge"

I choose option one as making up a plinth which is option 2 negates some of the features such as circular grooves along the side of the work piece and I was looking at making Delrin Sheaves that would require this feature, along with some metal bending dies.

Turns out that had I gone wth the 4D, I would have had the same problem as the centre height is the same for both frames, only the #3 has the lower height.

Walter


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