Big bore chuck?

125mm 3-jaw Chinesium chuck from Ketan at Arc Euro Trade. This is only £49, yet reasonably well made.

Looks and feels pretty reasonable considering.

The back plate is diecast. It's little more than a chip guard.

With the plate removed and the 3 drive pinions out of the way, the scroll bevel gear should come out.

Into the 4 jaw on the lathe.

And bore it out to 36mm. Plenty of meat left on the central boss.

Not a perfect finish but it's a clearance hole and can't be seen easily.

Now put it back together again.

And back in the box until I'm ready to mount it on the 4th axis.