Taper turning in lathe using Boring Head

[brian Rupnow]

I just read on another forum how Marv Klotz suggested using a boring head mounted in the tailstock with a "dummy center" mounted in it to do taper turning in the lathe. --WITHOUT setting the tailstock over. (Because its always a bugger to get set back to zero!!!) I have heard about doing this before, but today I decided to try it myself. It works like a charm!!! Thanks Marv. I took a couple of quick pics so others could see the set-up. ----Brian

[John Stevenson]

Wish I'd have thought of that.

.

[Toolguy]

I have been doing that for a long time now. The best part is it's cheap, fits any lathe, and you can use the whole length of the bed instead of just a foot or so like most taper attachments. ( Think rifle barrel ). I made a live center to go in the boring head by drilling and reaming the back of a piece of drill rod to .501,
turned a 60 degree point on the other side and hardened it. Put a 1/2 inch hardened steel dowel pin in the boring head, dropped a 3/8 ball bearing in the .501 hole with some grease and slid that on the dowel pin. The 3/8 ball is the thrust bearing, centered in the hole by the drill point and only contacts the dowel pin in one tiny spot, keeping friction to an absolute minimum. Also, for centers in the workpiece, I use ball seat drills instead of regular center drill. A ball seat drill looks like a center drill, but the cutting edge is curved rather than straight then angled. This allows a smooth rolling action of the part on the centers as the workpiece turns. I also put a little grease where the centers contact the work.

[Forrest Addy]

Yup.

You can get the initial taper setting pretty close by calculating the offset from the effective distance between the points where the work actually bears on the centers.

[rolland]

just as a matter of caution you might want to remove the two outboard set screws if there is nothing in the mounting hole. Unless you might want to hunt all over the shop for the one that came flying out and bounced off your chest and flew awwwwwwwwaaaay.
Don't ask how I know.

[Glenn Wegman]

Rolland,

I've been using boring heads forever for boring where the head is rotating and have never lost a screw.

What would cause them to just fall out and fly away when the head is stationary in this application?

[motorworks]

John
Did I not see that in your 'book'

[mklotz]

Originally Posted by John Stevenson

Wish I'd have thought of that.

.

Very funny, John.

Before you send a quartet of Cotswold shinkickers (or, worse, Morris dancers) after me, let me point out that I never said the idea originated with me.

[recoilless]

http://bbs.homeshopmachinist.net/showthread.php?t=28940&page=2&highlight=boring+hea d+in+tailstock

Lots of references to it in search, looking back on some REALLY dry John S. moments.

[x39]

How does one insure that the center in the boring head stays at center height relative to the head stock?