What's the cause of board slipping on sand paper belt?

[badbert]

I always try to use 14.5" wide boards or my 14.5 sleds. I have never had the roll under problem since I started this practice. Always thought an auto centering bar would solve that problem. Make sure the wood is always applying pressure to the center of the belts. The belts last a lot longer too!

[bergerud]

If you do notice that your belt has drifted sideways, you need not take it all apart to move the belt back.

http://forum.carvewright.com/showthr...537#post171537

[TurtleCove]

I am not sure. Years ago when drifting belts and roll ups seemed to be more of a problem, LHR always blamed it on head pressure. I suppose if the head pleasure is large enough, the belts cannot move sideways. The board will not let it.

Your problem must be something else. Maybe the squaring plate is not square and the board forces the belt sideways.

Hmm, that could be. I have had head pressure issues. Too high. But, I don't understnad how that could cause belt drifting.
Non-square squaring plate makes more sense.
I'll check it out.