"george" wrote in message
ups.com...
Check out your local tractor supply store (TSC or whatever is in your
area). They will have replacement blades for bush-hogs used on tractor
equipment. Many of the larger HP designs are pinned about half way out.
The center section or even the end sections may be just what you want.
These are tough and have holes already machined in them.

36 inch mower blades are readily available, of course. And the OP could
"double up" to get the thickness required. Battlebot people probably have
safety specs for this. Also, I think there are legal limits for RPM for each
blade length, at least for OEMs. I think a 22 inch blade has a 3100 RPM
limit. 26 inch blade is 2600 RPM