We are about give our Altendorf F45 a tune-up. We've done this several times and have got most of it figured out. As part of a preventive maintenance program we decided to change out the six nylon sub-rollers. The two at front and back are obvious. I can remember the Altendorf salesman describing the process for accessing the middle two rollers but I can't remember what he said.
As I recall, it had something to do with the black plastic gizmo that is exposed on the top part of the beam when the stroke is at either extreme. I think it had something to do with disassembling the beam for shipment. If anybody is familiar with how to change these center rollers, I would sure appreciate to know.
From contributor M:
Mine is an '02 and there is a trolley and when you push the carriage all the way forward it is somewhat exposed, and has a grey rod with a black knob. You pull the black knob towards you and continue to push the carriage forward. You should have easy access to the rollers. Are yours that worn, or is it just out of adjustment?
The way I typically adjust them is so the subrollers are loose enough to turn with your fingers (as you move the slider) until they are approx 8-12" from the main table (not the extension tables). I check the 4 subrollers on the right side of the slider against the right side of the main table and the 6 left subrollers on the left side of the slider against the left side of the main table. At that point they should be tight enough so that they cannot be turned with your fingers (or cannot be prevented from turning with your fingers while moving the slider).
Older saws that use phenolic slides will be more difficult to dial in since the phenolic tends to wear. It will be almost impossible to put your fingers on the subrollers on older saws as well due to the shape of the slider extrusion. In this case, use a marker or some sort and mark lines around each subroller, and then watch them from the end of the slider to see when they begin to turn.
As it turns out, the original wheels were in pretty bad shape. Some of the bearings did not turn smoothly and some the nylon wheels were cone shaped. You couldn't tell this from running the machine. Our cuts were all square and the slider seemed to run pretty smooth, without resistance.
I should comment that we are not a high-production shop. This would suggest that maybe these wheels should be part of a preventative maintenance program every couple of years.
For what its worth, Altendorf has upgraded the subrollers with a new type of bearing which you may have received when you replaced yours. Rather than the older style using a metal shield on the sides (covering the ball bearings) they have moved to a plastic sealed type. This should keep a lot of the dirt and sawdust out of there and your slider moving smoothly.