Crank Diameter

[Alan Worland 1Participant @alanworland1]

I am machining the crankshaft for a Stuart Turner No 4 the drawings of which suggest the main bearing and big end diameter is 7/16

There is plenty of material to come off that I have decided to make these bearing surfaces 0.500 – the main bearings and big end will accomodate the extra.

Has anybody else done this and might there be a problem I have not thought about?

 

[Alan Worland 1Participant @alanworland1]

[John OlsenParticipant @johnolsen79199]

It will not cause any problems, and is a good idea if the engine is likely to do any hard work. The Stuart engines generally are semi-scale, eg they are not scale models of a particular prototype, but are proportioned as if they were. So the journals are smaller than they would be if the engines were intended for hard work.

 

regards

John

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