Curved spoke flywheels

[sp1nm0nkey]

What's the best way to cut the spokes for a flywheel like the one here http://www.stirlingengines.org.uk/thermo/harrie.jpeg . The only way I can think of right now is mapping out the whole thing and then clamping the piece off center on a rotary table 5 times. Is there any other way?

[Geof]

Originally Posted by sp1nm0nkey What's the best way to cut the spokes for a flywheel like the one here http://www.stirlingengines.org.uk/thermo/harrie.jpeg . The only way I can think of right now is mapping out the whole thing and then clamping the piece off center on a rotary table 5 times. Is there any other way?

Use a CNC machine

By the way you would need to clamp it on a rotary table at least 10 times doing it manually.

[sp1nm0nkey]

That's what I thought... but if you cut around 200 degrees or so (just a guess), then go back to zero, increase the diameter, go back down, and cut around 80-ish degrees, you'll cut the back and front of a spoke, since all the holes are moon-shaped. If you do that 5 times you'll cut all the pieces out... I might be wrong about that though, but isn't there an easier way to cut the spokes?

[Geof]

If you had a little rotary table mounted the correct distance off center on a larger rotary rable you would not need to keep reclamping.

But you are doing this for a hobby. Surely the enjoyment is in the process as much as the end result. Looking for the easy way you are cheating yourself of the sense of satisfaction that comes from meeting a challenge .

[sp1nm0nkey]

There's challenging, and there's tedious. There's also enjoyment in finding a clever way to do something.

[Geof]

Originally Posted by sp1nm0nkey There's challenging, and there's tedious. There's also enjoyment in finding a clever way to do something.

Okay, you win, I agree with all three.

[sp1nm0nkey]

On that note... maybe I could could machine a jig of sorts with 5 holes in a circle that I'd press fit the fly wheel onto. I'd drill 5 holes into the flywheel stock and countersink them almost all the way down, mill each spoke but not all the way down, just above the screws. Then, I could take out the screws and take down the remaining material on the lathe.

[Geof]

You can probably avoid the countersunk screws.

Fully machine the flywheel on the lathe; this makes it a solid disc.

Machine a disc which will be your rotary table fixture and have a recess that the flywheel OD fits.

Drill your five locating holes in this disc and also drill a tap some holes around outside the recess.

Clamp the flywheel into the recess with some large washers on bolts in the outer holes in the disc and then you can fully machine the spokes on the rotary.

[307startup]

Just center your rotary table on your mill table, use this as your zero reference point. Divide 360 by 5. Start at zero on your rotary table. Move your mill table the distance you want the rotary table to cut the curve, and at the end of your cut, return to your zero. Adjust your rotary table 72 degrees, and this becomes your new zero. Move your mill table the distance you want...repeat 5 times. No need to do multiple setups.

[Geof]

Originally Posted by WYLD Just center your rotary table on your mill table, use this as your zero reference point. Divide 360 by 5. Start at zero on your rotary table. Move your mill table the distance you want the rotary table to cut the curve, and at the end of your cut, return to your zero. Adjust your rotary table 72 degrees, and this becomes your new zero. Move your mill table the distance you want...repeat 5 times. No need to do multiple setups.

WYLD did you look at the link? The five curved spokes do not have a common center. The part has to to be mounted so the center point for each individual spoke is at the center of the rotary table in order to machine that spoke.