Walking Belts

[SAA3840]

Can anyone shed some light on why my belts keep walking off the rollers? After every project, I have to trim about 1/4" off the belts, both of them, in order to get the board sensor cleared.
I've removed the rollers, cleaned and lubed them and it keeps happening.
Could the springs have lost some of their 'springy-ness'? I'm at a complete loss.

[AskBud]

Several things to do/check.

First:
Head level? How do I check that? Take some 3/4" stock and make 2 pieces about 16" long and 2" or 3" wide. Run them through your table saw, or planer (so the edges are truly parallel). Place them in the unit (on edge) just inside the 2 squaring plates on both sides of the machine. Place small pieces of paper on the top of each board (where the roller will touch). Lower the head using/moving one of the papers as a "Feeler Guage", to the point that the roller just touches, but the paper can be removed with slight pressure (but does not tear). Now, without changing the head, check the other three papers.

Next:
I presume that you are using a variety of stock, and sometimes a sled. That should eliminate uneven/tapered boards. However, constant use of narrow boards could cause your problem. Excessive head pressure (80 lbs is suggested) could also cause the issue. You may check this with an ordinary bathroom scale.

There have been some occasions where the belts were not the same measurement the entire length, which would cause the problem. This could be checked by flipping the belt 180 to see if it moves the other way. Spring tension would be my last expectation, in most cases.
AskBud

[SAA3840]

Thanks Bud, I'll check all of these. Most of my projects are in the 9" to 11" width range. Very seldom do I carve anything narrower.
And I'll be ordering some new belts soon, too. LOL

[unitedcases]

I think everybody has belts that walk. I reset mine every 20-30 hours or so and it has become so much of a habit that its part of a routine now. Plus when and if I get a rolled belt, I just cut the bad part off and reset it. There is a trick to resetting them without having to take it out of the machine. Here is the link http://forum.carvewright.com/showthread.php?10651-Traction-Belt-Trick

[AskBud]

United Cases makes a point about moving/adjusting the belts that I did not mention. Thanks UC.

Here is my old post on that process, using the front belt as my example.
AskBud
http://forum.carvewright.com/showthread.php?12560-Sandpaper-Traction-Belt-Adjustment&p=103671#post103671

[Digitalwoodshop]

I am with Ask Bud on this, it is most likely a head that is lower on the bit plate side and it makes a funnel shape when clamped down and puts side pressure on the sand paper belts.

I had my first front belt roll under last week... It was a full 1/2 inch rolled under.....

I just rip off a strip of belt when ever the paper is even with the end of the roller.

Picture 3 shows rip and rotate....

AL

[liquidguitars]

I just cut .50" strip off yesterday on my new retro ebay CW, but only after loosing a violin top to the old belt hits o ring o ring moves to the back of the AUX top carves .36" longer maneuver.