Hi John,
I had read most of your book Care and Repair of Shop Machines and it’s good with very practical info. I am adjusting my planer (15″ Powermatic) which has a segmented infeed roller. I have read your book about segmented rollers but I still don’t understand it. How does a segment run nearly concentrically? How are the segments high and low points 180 degrees apart? I think a diagram to show how to adjust infeed roller would help me. Thanks.
Craig
Replies
Craig,
Each of the segments on a segmented infeed roller are free to move a bit off center to adjust to different thicknesses of stock when feeding more than one board at a time, side by side, into the machine. The segments float on the drive shaft, each segment being kept roughly centered by several springs inside of each segment. Because of this, the segments are almost always a bit off of center and don't supply a reliable surface to measure the true height of the infeed roller assembly.
On many machines you can nudge a segment into running concentrically by tapping it into alignment while measuring its concentricity with a dial indicator set up on the planer bed. When the indicator doesn't move while you rotate the shaft through a full revolution, the segment is centered up and can then be used to set the height of the roller assembly. You will need to center up one segment near either end of the shaft to make the adjustment to the roller's height while also keeping it parallel to the bed. Since you will have to rotate the shaft quite a bit while getting the segments running true, you will need to unhook the shaft's drive chain so that it can turn freely.
Sometimes you can't get a couple of segments to run centered because the springs push them back out of alignment as you try to center the segment up. In this case the only alternative is to let the segment run off center and find the midpoint between the high and low points of the segment and use the midpoint to take your height measurement against. This approach is as accurate, in theory, as getting the entire surface of the segment running true.
Having said all this, unless you have reason to believe that there is a problem with the height setting on the infeed roller, or the roller assembly has been removed and must be reset, you are better off just leaving it alone since it is rarely a critical adjustment for getting the machine to work well.
John White
Hi John,
Thanks for the advice. I will leave the infeed roll alone since it seems okay.
Craig
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