Jason- I do like these engines,I am making Rob Roy which has been under way for some years and its a long time to see the final results, these engines would give quicker satisfaction, do you generally fabricate or use castings and which would you recommend for a simple starter engine

Mick

That turned out well Jason. As always an impressive result in double quick time.

Jim

At long last the Stew Hart's Popcorn engine is complete.

I ran into a couple of difficulties when reassembling it after stripping and painting; I discovered that somehow I had managed to bend the piston rod, which is a short piece of 4mm dia steel, and when I remade it the M4 thread I put on the end using a brand new thread die was seriously horrible and barely engaged with the crosshead. The bronze ball whistle valve which previously held air very well now leaks and will need to be sorted, hopefully with the simple replacement with a nitrile ball.

Anyway, here's the evidence:

And for those of you not too bored yet, a video:

Jim

A nice little popper Jim, award yourself a gold star…

Geo.

Nice on Jim, I like the engine turning.

Nice brasswork on your cylinder too George.

Having discovered that my two second-hand Chinee milling vices were 100 thou different in height, I spent a day correcting them. While I was at it, I replaced the grooved, non-round,soft-cheese pull-down hemisphere (only one, the other was missing) with 5/8" bearing balls that had a flat turned on them in the lathe. Then I milled the angled face that said hemisphere slides on so it was flat, rather than corrugated.

After putting them back together I finished milling the edges of the 500x210x10mm plates that are going to be the collet draws in my HLV cabinet.

I wouldn't have noticed or even thought about the vices being different heights if I hadn't been holding the aluminium plates vertically, supported by both vices. Bit easy to spot when you have the three plates on the bench on top of each other to measure them for the final cut and notice that the edges don't line up .

Edited By Mark Rand on 13/01/2018 22:02:25

You didn't mention how you machined the internal teeth. The acrylic test doesn't give the game away. Did you use an end mill, a slotting attachment, file……?

We should be told!

Murray

I've just been cutting some 70mm x 20mm flat bar up, to make a new ball turner.

I had a quick check with a square that the bandsaw was set square. Cut the first bit off, went to the mill to clean up the sawn edge. It cleaned up within .008"!!!! I was well happy! Set the saw going on the next bit, thinking about gloating later on here about how good the bandsaw is!

Next 3 bits came out about 60 thou out of square…….

What's that saying about pride before a fall. though I'm sure there is a better suited saying…….

Jim