He may be trying to cut way too much log for the blade and saw.

Last fall I ripped a well dried 6"x8" beam into boards with a 1/2"
Timberwolf blade. I eventually got several usable boards from it, but had
lots of problems with the blade bowing in the wood. I was cutting very
slowly too, so I doubt the feed rate was an issue.

trying to tension a 3/4" blade might bend the frame.

I have only used 1/2" blades, except for the 3/8" green wood blade I have
on the saw now.

Anthony Watson
www.mountainsoftware.com
www.watsondiy.com