Mini lathe internal dome tool

[Stevohdee]

I don't watch a lot of tool builds. This one caught me, you circumvented the common solution; a yoke. I like it.
Extending the hinge pin, allows a reference to set accurate radii, via height gauge. Another method would leave holder in place, referencing with a known size block against a surface, zero a dial and back up, then set protrusion of cutter.
A hint on lapping. Cutting action improves by alternating straight strokes, rotating the part 15°-45°, produces a crosshatch [aka 'lay'] before final desired finish. Another technique is tracing figure 8's.

Thanks for your advice, I had to Google yoke but came up with a thing to align two bullocks but a bit more digging found some pertaining to machining, still confused. I'd have to see one in action to fully understand how one would make an internal dome. Was thinking of center punching a dot in the middle of the hinge pin then using a divider or compass to set radius. Will try your tips on finishing on the next build, thanks, regards steve

Hang on, found it... A ball/radius turning attachment has a yoke, so it can be set up to do inside radius, got it, thanks again