Replies

1. 
   MBerger | Oct 26, 2006 05:59pm | #1

   It sounds to me like your abrasive strip is either mucked up or is not completely flat against the drum.

   The burnishing could occur from the abrasive being clogged with dust or even glue. If this is the case, clean off the abrasive with a rubber eraser or change the paper.

   If by "trough" you mean gouges in the wood, that can be caused by a high point in the abrasive, possibly caused by improper installation, or something getting stuck on or underneath the abrasive.

   Do either of these sound plausible? If not write back with more detail.

   Matt Berger
   Fine Woodworking

1. 
   alfonso | Oct 28, 2006 06:44pm | #2

   thanks, but I've already rulued out the conditions you mentioned. the burnishing and/or the slight troughs are along the width of the drums. could this have something to do with the feed rate ?

2. 
   JohnWW | Oct 31, 2006 06:13pm | #3

   Crosswise marks would indicate a few possible problems:

   1.  The stock is not feeding steadily through the machine, it is stalling for a fraction of a second and then moving again.  Unless you look closely you might not notice the slightly uneven feed. 

   This could be caused by a number of faults.  The conveyor belt could be worn out, or stiff, or the drive rollers are glazed, or there isn't enough tension on the belt, allowing it to slip on its drive rollers.  Dull paper on the drums or taking too deep of a cut can also cause hesitation and momentary stalling.  A problem with the feed belt drive system is also a possibility.

   2.  The troughs could be caused by something like a bad seam on the belt, or a spot of built up of sawdust on the back side of the belt, which is lifting the stock slightly and causing the deeper cut.

   One last possibility is a fault with the drums, a bad bearing perhaps, or a sticking or loose bearing housing that is occasionally causing a drum to move up and down slightly.

   John White