Getting thru the hard skin of a cast flywheel

[bigal2749]

I want to modify an old cast flywheel by cutting a 6 mm channel to a depth of 1 mm into the side and boy it that hard! Cutter doesn't do much. Have seen discussions in the past that you need to address the hard skin of the metal when it was cast.

Any suggestions are greatly appreciated

 

[jack404]

G'day Al

i use whats called a negative rake cutter that takes valenite brand indexable cutters

these rip through cast skins with ease

a old bloke who lives in vermont USA put me onto these a couple of years ago

never looked back or wished to.. they work

rusty axles are another thing the hardening process of rust on the induction harden axles makes them hard on cutters too this works well too

jacks 2 cents worth

cheers and good luck

 

[Mainer]

It may be more than just the skin. Cast iron, having a lot of carbon in it, can get extremely hard if it cools rapidly after casting. If the hardness does seem to extend clear through the piece, you could try annealing it. Our electric oven has a "clean" cycle that gets quite hot, and I've thought that running a piece through an oven clean cycle might be a good way to anneal it....assuming it's small enough to fit in a kitchen oven, and you have an oven with a clean cycle.

 

[Rustkolector]

Mainer,
According to a casting supplier that I use, iron castings are annealed at 1600F for about 8 hours, then slowly cooled. Your electric oven cleans at below 600F, and will not be of much use in annealing cast iron.
Jeff

 

[Metal Butcher]

Unfortunately Rustkollector is correct. I dabbled a little bit with heat treatment using a high temperature oven designed specifically for that purpose. Its the only way to deal with annealing cast iron.
Trying the suggested cutters or angles may be the only other way to deal with that tough crust.

Here's a link to some basic information that's worth reading.

http://steel.keytometals.com/Articles/Art112.htm

-MB

 

[radfordc]

Joe Webster suggested using a barbell weight as a flywheel on his Webster engine. Boy, that was the hardest crap I've ever tried to turn. Carbide bits barely touched it...and it wasn't just a "skin" on the surface either. I guess they don't bother annealing barbells.

Charlie