GP crank taper angle?

[vegansydney]

Does anyone know the angle for the taper along the edge of a GP/dl crankshaft? I watched a good friend / mentor measure one yesterday using an edge finder on his milling machine. We calculated 4.25°from start of the taper until end. It was measured 3 times and calculations checked each time.

Can anyone confirm 4.25° is correct? Does anyone have access to blueprints for GP/dl cranks--or any other useful information--that confirms or contradicts this angle?

Asking for a friend, seriously

[hullygully]

you could allways use maths to confirm it too bud,
'Tangent' (of opposite divided by adjacent) = 'Opposite' (1/2 of diameter differances from both ends of taper) /'Adjacent' (length of taper in the horizontal)