I have used knife edge sabre saw blades for cutting homasote.  They work great, unfortunately I have not been able to find them for some time (I still have a couple left).  I was excited when I read Kalitowski's comment but alas, the "part" number he supplies is not a Craftsmen part number.  It looks like a model number for something, but no amount of searching on the Craftsmen site would turn up knife edge blades.  Does anyone else know of a source for knife edge blades?

Did a google search and go this:

http://www.amazon.com/Vermont-American-Knife-30022-U-Shank/dp/B006GK9S1K

Rick

@tmaz - Out of curiosity, I did a Google search and found this:

http://www.commercial.sears.com/comsale/industrial/toolcat/ti.cgi/item.ti/4064?tool=9-28814

It is their commercial/industrial part # 9-28814.