A surface relative to a cylinder??

[tghs]

wondering on how the gland recesses inside the frame will get machined,,central cutter on a 1/4" rod?

[Jo]

The Jig plate needs to use the 1 1/4" and the 1" diameters on all parts as locators = one jig for the cylinder, pumps and that spacer, something like attached. Think a 1 1/4" counter bore with a suitable 1 1/4" to 1" reduction bush, then a pair to take the 1 1/4" counterbore to a 1/4" boss and 1 1/4" to 1" boss to register in the bores of the cylinder and pump.

Once you have started you need to leave the jig where it is for the second set of bores and do all three parts without moving the jig - I'd clamp some how not bolt it in place. If you look at my sketch you can see holes to hold the bushes in place and another set of holes round the outside which I would used for the clamp bolts.   

Jo

[Rod999]

             That plate looks like it would work just fine~ I see a very similar machine on youtube listed as a large duplex boiler feed pump - similar but not exact~

[Jo]

We seem to have gained a set of castings for a different Duplex Steam Pump, this one is the Southworth small Duplex pump 

I hope to learn more about them tomorrow (assuming they are offered up as the set of castings for our Thursday night Casting fondle  ) It will have similar problems for machining as your one 

Jo

[Rod999]

       I dug the steam cyl. out of the box  being it's next to be made ready, Here I'm just going to clean up the exhaust port, so as to scribe the center line & help find some squareness~