What is this?

[minimutly]

Do the axis of the holes relate to the facets of the cutter? Could be be part of a sharpening jig.

Yes, and as @8ob has clarified, they sit on top of the main machine so the diamond wheel can sharpen them.
It’s amazing how someone’s “what’s this” post on here can clear up mysteries.
Still some question over what make and model borer it comes from though - the setter is not a common van Norman.

 

[Dieselman 63]

Yes, and as @8ob has clarified, they sit on top of the main machine so the diamond wheel can sharpen them.
It’s amazing how someone’s “what’s this” post on here can clear up mysteries.
Still some question over what make and model borer it comes from though - the setter is not a common van Norman.

Must be something British to have a M&W mic embedded in it

 

[Seadog]

The loose bits are nearly all for holding down - the half moons at the bottom, with the clevis pin connecting it to the threaded rod, with the bit at the top to allow the tapered female bit to be slotted by the tapered male bit, which gets screwed in to clamp the forged bit with the part members to be clamped down.
I can’t see the bit that locates the cutting head in the setter though? Or the borer itself, which would be worth a few quid I guess.
My old van Norman has a simple adjustable foot you engage with a washer on a threaded rod, then tighten as tight as you dare...

In my limited experience, the tool holder locates on a pin which holds it aligned to the micrometer spindle.

 

[minimutly]

In my limited experience, the tool holder locates on a pin which holds it aligned to the micrometer spindle.

So did you say that was a Burma borer @Seadog ?
Certainly the van Norman’s just have a slot, as in the pics above. (Post no 38, clearer in the top pic). The cutter is set in the holder, which is adjustable, the cutter and holder slot into the bottom of the boring bar.

 

[Seadog]

Buma

 

[Dieselman 63]

For the meantime it makes quite a nice Lock Screen!

 

[minimutly]

Mystery fully solved then, Buma borer. Someone somewhere has a Buma borer without the toolkit @Dieselman 63

 

[Dieselman 63]

Mystery fully solved then, Buma borer. Someone somewhere has a Buma borer without the toolkit @Dieselman 63

I’m not so sure. The case here and the setter tool look very different from mine.

 

[Dieselman 63]

Got it. Whatton. Now I need the machine.