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Hemingway 1/12 Ransomes and May horizontal engine

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samc88:
I bought this early last year as a present to myself and since the dividing head is nearly done awaiting a few bits in the post thought I would make a start, starting with the base. Similar to the S50 I did I wasn't keen on the cast in bosses for the mounting studs so I machined them flush and will replace them with washers. The hemingway castings are slightly undersized which will be an interesting challenge but they do machine nicely.

samc88:
A little unconventional I guess but I started with the water pump, theory being I get the feeling for the kit and as it's only run on air it's a relatively unimportant part, plus if I can do the fiddly little."extras" then hopefully the engine itself.goes as well

I lost a few pictures on my old phone but basically I machined the bosses either side of the pump as well as skimming through base itself on the lathe. The lower suction fitting and the end plug have been made (no pictures I'm afraid) and the top cap has been made, I took pics of this, the threaded section was machined and then the bronze put in the 4 sided collet block to machine the square.

samc88:
The Base was then machined square, the casting is lundersized but that's not really affected anything so far. No.43 holes drilled and fitted with temporary 8BA screws to check it fits. Still need to machine where the screws sit and the central rib needs thinning too.

That's where I'm up to so far

Jasonb:
Off to a good start

Was it just teh base that came up undersize? I wonder if the pattern was originally meant for cast iron rather than Aluminium. You could think about adding new bosses for teh hold down bolts, just a shallow counterbore and then JB Weld in some rod an dmill flat when set, this would be truer to the original.

One other thing I noticed was how far back your ER collet is sitting in the nut. The way they should be used is to snap than into the offset ring within the nut first and then screw the nut/collet onto the thread. Not only does this hold the collet more concentric it will also pull it easily out of the taper when you undo the nut. You can also damage the collets by not clicking them in.

samc88:
Thanks Jason, usually I do that with collet, not sure why I didn't this time, the end mill was fitted the way you say. I will probably do as you say as well in regards to the bosses, I only milled the cast ones off as there was quite a bit of excess material around them which wasn't the nicest looking  to say the least, not only was it excessive but it was all lumpy as well

Most of the castings are slightly undersized with the exception of the cylinder and steam chest, the water pump one at the minute is about 20 thou under in most dimensions, the base is about 40 thou smaller than it should be but Id rather it look right with clean edges, I did wonder if they had lost the patterns and used a casting as a pattern

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