Tail Stock Taper Turning Attachment

[petertha]

You do really beautiful work Doug!

Coincidentally I was just setting myself up to do some taper turning in my 14x40 lathe which has no taper attachment. For better or worse I got an el-cheapo 2" boring head & MT3 arbor to fit my tailstock. Anyway, now I see so many good features & advantages of your design, I guess I'm going to have to put that on the Make-It list. I have a couple (ok, maybe more than a couple) questions related to this I would like to tap into your expertise.

When you set up the attachment into tail stock, I assume you position the block horizontally so its traverses across the bed correctly. I can roughly do the equivalent of that with the boring head as it has a flat milled on one side. But I was concerned about 2 things here: 1) the whole assembly turning on the MT3 arbor and 2) unscrewing the boring head from the 1.5x18 threaded arbor. I'm told that even though the arbor is tang-less, it should hold securely. Do you think this is dangerous in terms of cutting pressure direction wanting to 'unscrew' the assembly either way?

Because the boring head has 0.500" tool holes, my plan was to make a 60-deg dead center from tool steel because I cant think of a good way to adapt a commercial tapered shank live center into a straight shank. I assume commercial live centers are hardened & ground. Do you see any issue with this?

In terms of the center drill holes on either end of work, I can see the potential for a 60-deg center to only contact a small line of the typical 60-deg center drill depending on taper geometry. Hopefully my pics explain. Ball ended centers might be a good plan, but that's another thing again. For insurance I got some some type-R center drills. Any words of wisdom in that regard?

Lastly, I've been thinking about how to set up the head when a specific taper must be cut. Because the length of part will be different every time, I cant think of a good way to pre-set the offset. Here's what I mean. If I start with accurate cylindrical stock, hold a DTI in toolholder so it contacts on center & register zero. Now move carriage over fixed amount say 4", then back out set amount to achieve taper angle, then screw the taper attachment displacement until DTI reads zero. Only problem is, now the whole part has rotated about the headstock center so the original reading is no longer valid. So... do you iterate this procedure until it converges to the proper angle for that particular length? Hope my clumsy description hasn't confused you.