Chipper/Shredder Blade Replacement

[greg273]

Anyone know what sort of steel is used for chipper blades? I'm having trouble locating a factory-made replacement for an older Olathe Chipper. Its a fairly large machine, a PTO driven model that my dads 30hp tractor could just barely operate...
Its basically 2 fixed blades, each about 5" by 2", i'm guessing about 1/8 thick steel. ( Honestly I havent looked at it in about 5 years, so thats guesswork there. I'm hoping to tear into it again sometime soon).
The blades are attached to a heavy iron cylinder with setscrews. I'm thinking I may have to fabricate something, anyone have any advice on a certain grade or type of steel I should use?

[Darren]

Have you asked these folks? They may have a source for the knives you need.

http://www.arboristsite.com/showthread.php?t=17620

If you have to make your own I'd have a machine shop check the old one for hardness. They might be able to give you an idea on the material. I'm not sure how much balance will play in making new parts. Heat treating to get the correct hardness seems to be critical.

""The knives we sell are made by Zenith. They are made from "chipper steel"
which has a hardness rating of A8. At the cutting edge, Zenith knives have a
Rockwell hardness rating of 56-58. This goes down to the mid 40's at the
center of the knives near the bolt holes to prevent the knives from being
brittle and shattering. The steel has been heat treated and annealed 3
times. Hopefully this answers your question. Let me know if I can help with
anything else."

Here's a link to Zenith.

http://www.zenithcutter.com/products/treeCare/

[greg273]

darren, excellent link, they might just have what I'm looking for. Thanks!