I decided I needed some 10BA nuts for this and that I'd make them rather than going to the trouble of buying them from some specialist shop.
First shot is a bit of 7/16" hex drilled with some 5/32 round brass held in it by a grub screw. I have alot of these hex offcuts,
then milled the hex, 3mm across flats, using the side of the endmill
Next drilled, initial tapped, chamfered and parted off in the lathe. Finish tapped by hand. They're a little dirty. I didn't notice that until seeing the photo because they're so small
Also made some threaded rod, both 8 and 10BA. I borrowed Jo's trick of cutting a bit and then moving it further out of the chuck
Here's an 8BA grub screw that will be used to hold the collars on the rotary valve rod. The screw is sitting in the corner of my piercing saw which I used to put the slot in it
I also drilled a couple of holes for the inlet into the cylinders. Had to put some brass rod in to help guide the drill. That's it clamped with the G-clamp. I'd previously placed the centre drilled holes in the correct position on the milling machine
Here's a shot of the two holes. You can see how they're slightly offset, by 1/32" either side of the centre line
Hopefully that wasn't too incoherent. I'll try to pull it back from the madness a little next time
Steve