Silly question:

Apart from Morse Tapers, what needs that level of precision? In my 30 odd year career as a designer I've never found anything where I've not been able to redesign it so +/-1 degree isn't adequate. I've often felt some vague sense I'm missing a whole heap of precision as a result, and should extend my range of experience. Hence my enquiry.

Regards

Richard.

My current project is a D1-3 spindle upgrade. The register taper is 7degrees 7&1/2 minutes. It's a pretty sticky dimension, right down to checking it with spotting ink and stoning it to round. (My lathe bearings are tapers in class 3, and only get me to about 0.0005" egged).

Another upcoming is as you note, a Morse taper. This one is an accessory that cuts square holes. It mounts in the tailstock. I'll need it for making the cams for my chuck mounting spud.

In the future I will have to make some special B&S taper centers for my dividing head.

In the past I used to service the hob spindle bearings on G&E gear hobbers fairly often. Usually the owner ran them without keeping them in order, so the bronze taper was thrashed. It's easier to set up the compound to spec than to set up the spindle and dial in off of it.

All of this assumes that the headstock is in alignment with the lathe bed of course.