I am installing a new houseing mandrel on my Craftsman Mower 46" cut. There are 3 bolts do they self tap into the housing mandrel, because the mandrel has no threads in the bolt holes on the housing mandrel.

Tom B, May 2009

The mandrel you speak of in my country is called a bearing, and yes the bolts do self tap. But be careful though not to over tighten the bolts as they could strip the bolt holes as the mandrel is made of aluminum and the bolts are made of case hardened steel.
Hope this is of help to you:

Mickey-G, May 2009