Built up crankshaft

[JimbobParticipant @jimbob]

Gentlemen

Having assembled the components of a built up crankshaft (single cylinder engine) I am having difficulty getting everything into correct alignment.

Any advice on this would be very welcome.

Thankyou

[JimbobParticipant @jimbob]

[JasonBModerator @jasonb]

Have you left the main crankshaft as one, or is it in two pieces. Usual practice is to leave as one, join the parts and then cut out what's not wanted between the throws, if you have already cut it then you need to set up a pair of vee blocks against a straight edge.

What joining method will you use and are the holes drilled, reamed or bored?

J

[JimbobParticipant @jimbob]

Hello JasonB

Thanks for your response. In my wisdom(!!) I made the shafts as separate pieces.

The holes in the crank webs were drilled undersized, then reamered while clamped together, using the mill. The shafts (or part engaging with the webs) were then turned to give a light interference fit with the intention of locktighting and pinning.

Having just spent time studying the problem I had pretty well decided to do as you say. I will turn up a one piece shaft and also make up a suitably sized spacer to go between the webs.

Thanks again, and I won't try to be so clever next time!

[Author]

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