Machining a throttle butterfly...

[the phantom]

Does anyone know how you go about machining the angle present on the edge of a throttle butterfly? I'm no machinist, but our machinists out back dont know either!! Or is this a job for a CNC...

[Mark]

It's listed in the workshop manual for the vehicle (at least for Toyota's)

[the phantom]

Hey Mark,

So your saying that the Toyota manual actually has instructions on how to make one?....which manual? I don't want a replacement, I want to make a bigger one, but dont know how to go about machining that peculiar edge shape? Thanks.

[Mark]

Ah I see, my mistake.

I'll talk to a turner and fitter I know, I'll get back to you.

[ylwgtr2]

put the original one in the chuck and then angle the tool to the same angle and then take the reading...then make you new one and put the same angle on it....why dont your machinists know this???Its not so difficult

[the phantom]

Yeah, well I figured it out. I have to make a tool that supports the new blank throttle plate at the required angle to the lathe chuck axis, and machine it at the edge parallel to the chuck axis as it spins. Its not just a matter of measuring an angle...thats easy. You cant just put the blank in the lathe and angle the tool! The actual shape formed is an ellipse. I agree that our machinists should have suggested something. I bet if I told them I'd pay them Sunday rates to do it they'ed be full of ideas! Anyway, thanks.

[Mark]

Hahha, so true! (sunday rates)

Pretty much what you've said is what I found out.

Good luck