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

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.