Ron,
The following is my conclusion after a similar experience.
My c3-31 was delivered in 2017. The scoring unit (not a separate motor) was used for several months building cabinets for the shop, then lowered. Several months, or maybe a couple of years, passed before an attempt was made to again use the scoring unit. The belt was found to be broken. During a call, the Felder tech suggested that I had left too much pressure on the belt, that is, I had not adequately lowered the scoring unit. A new belt was ordered and installed. After use, the unit was lowered more than previously. The next time the unit was put into play, the belt was again found to be broken. This time, a Felder tech suggested that I had not left enough pressure on the belt. Hmmmm. A new belt was installed. I cannot remember how much the unit was lowered after that use. Recently, I realized that the belt had fallen off the pulley. On examination, there was an area of thinning in one isolated area of the belt.
My conclusion is that the unit had been lowered too much, leaving slack in the belt, allowing the motor shaft to spin against the belt without turning the unit.
In the past, when a 300mm blade was in use on the c3-31, the scoring blade was removed. When a 250mm blade was in use, the scoring blade was often left in place.
My plan for the future is to lower the unit enough to be out of the way, but not so much that the belt slips. There is a slit in my zero clearance insert for the scoring blade, so when that blade is in place, it is easy to visually see the depth to which the unit has been lowered. When the scoring blade is not in place, it is a challenge to know how much to lower the unit. In the future, when a 300mm blade is in place, I will attempt to identify the proper level for the scoring unit before replacing the zero clearance insert.
My questions for the group:
1. Does the above seem like a reasonable explanation for the broken belts?
`2. Should the blade of the scoring unit always be removed when not in use?
3. If the main saw blade is rotated by hand, and the shaft of the scoring unit spins, does this imply that pressure on the belt is adequate, or is it possible that the main motor shaft will spin with such speed and force that it will still slip on the belt?
4. To avoid all of the above, should the belt be removed when the scoring unit is not in play?
Thanks,
Steve Hubbard
Nashville, TN
