Making a radius/blallturning tool using a boring head

Since I recently bought a boring head and seeing youtube videos of people using a boring head for turning radius and ball I thought I would make my own holder.

This is my plan and would like any pointers please. I also would like to know whay size to bore the hole for the bearing so its a slight intereference fit

Click on the drawing to make it bigger

Edited By petro1head on 21/04/2017 17:40:56

I don't know what kind of bearing you intend to use, but I assume an Oilite bush should do the job. I have used such bushes in some of my projects, and make the hole for the bearing about 0.02mm under size.

Thor

This is the bearings I am buying - **LINK**

Here's a couple of links that may be of use:

***Link***

***Link***

Or you can just use an adhesive.

Thor

coulc i make this out of an aluminium billet or steel

Hi Guys
Its a good idea' here is my one I made

Ali or steel???

Any more photos, your maybe a better idea than mine?

Hi
Only a close up of cutter shape not very clear 

Edited By Nobby on 22/04/2017 17:57:34

I based mine on the design by Reed M Streifthau given in the second part of this link **LINK** .

I made the spindle with a female R8 taper so I could share the boring head with my Bridgeport. Didn't bother to invert the adjustment system so as to put it on top. Don't find it any great disadvantage with the adjuster on the bind side. No separate bearings. Just took care to get an accurate fit with really good finish on both bore and spindle.

A basic boring head is probably around 2" longer than the compact slide assembly used in most purpose built designs. So you need to pull the head as far back to the mount as possible. If the tool projects too far there won't be enough slide travel to bring the tip back onto centre line. Something to watch closely with smaller machines. I didn't pay special attention to this figuring there would be plenty of room a as my lathe is a 10" swing Smart & Brown 1024. although it fits fine there isn't a lot of excess slide travel, maybe 1/2". I figure a bit more attention to detail would have won another 1/4" to 3/8" and might well have been needful on a smaller machine. The pain shank carrier shown in the drawing on the first post can certainly be pulled back a bit further than my R8 spindle version. For smaller machines it may well be worth enlarging the body slightly so the flange on the shank assembly can be pulled back into a counterbore winning even more space.

Well worth the effort as it works just fine.

Clive.

Edited By Clive Foster on 22/04/2017 19:06:57

This link **LINK** shows an interesting variant with the ball turner integrated into a QC system toolholder. The boring head is also pulled back into the carrier rather as I suggested in my earlier post.

Were I to make another that is probably the design I'd use as a basis with appropriate modifications to fit my Dickson QC system. More work but having an integrated unit makes it easy to fix the tool height dead on centre. If you merely put it in a carrier when required it has to be adjusted dead on centre before you can use it. Not as easy as it seems due to the inherent flop around tendency.

Clive.

I have a 2" boring head with a long 3/4" shank. It fits nicely through the AXA boring bar holder for my QCTP. The shank projects far enough from the tool holder that I can attach a clamp-on handle. No bearings or bushings needed. Actually, the only thing I needed to make was the clamp on handle.