taper measurement

[Dougie SwanParticipant @dougieswan43463]

I need to make a new flywheel for one of my full size engines, can anyone tell me how to measure the taper on the crankshaft acurately so I can machine a new one

Dougie

[Dougie SwanParticipant @dougieswan43463]

[Michael GilliganParticipant @michaelgilligan61133]

Dougie,

Rather than relying upon any form of Angle Gauge; I would carefully measure the diameter at two locations, and the distance between them.

Follow with some calculation, and round the answer to the nearest credible figure

MichaelG.

[jason udallParticipant @jasonudall57142]

Like Micheal says measure diameters and distance between…but use that to define machined taper rather than angle.

[MICHAEL WILLIAMSParticipant @michaelwilliams41215]

A millwrights method used when parts are too big to handle easily :

Boreout a short piece of round bar by trial and error until you get an exact fit on shaft taper – tested with blue or chalk if nescessary .

Make a tapered plug to fit .

You now have an accurate and portable taper gauge for boring flywheel .

MikeW

[Nigel McBurney 1Participant @nigelmcburney1]

You may find that when measuring the tapered shaft it doe not work out to whole degrees,A lot of tapers in engine work were were defined as a one in x taper, ie most magnetoes had a drive shaft with a a one in five taper (11 and a bit degrees) Istead of making two gauges why not make a tapered hole in the round bar and with trial and error machine the taper until it fits the crank, leave the top slide set over and then bore the taper in the flywheel at the same top slide setting, thats how i .make the tapered bores in magneto gears and sprockets, make sure the boring tool is exactly at centre height in order to achieve a correct taper.

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