Replies

1. 
   SgianDubh | Nov 21, 2004 07:28pm | #1

   Tearout can be a problem with all sorts of woods NC, not just oak, although the problem is sometimes more evident in this and other woods with marked differences in the hardness between spring and summer growth wood. Woods like pine, ash, chestnut, etc. all tend to have marked difference in hardness from one the growth ring as it transforms into the next. On the other hand finer grained woods like walnut, mahogany, beech and maple can show tearout too.

   A 1-1/2" dia. bit should work well at about 18,000 to 20,000 rpm, but sharpeness will affect performance. Feeding against the rise of the grain relative to the edge being worked certainly doesn't help just as hand planing against the grain often tears out the wood. A too fast feed rate might be contributing to the problem-- on the other hand a too slow feed rate will result in burning. Too heavy a cut doesn't help either. Erratic feed speed and pressure can also contribute to the problem. The dryness of the wood also can have an effect, drier wood being somewhat more brittle.

   I'm guessing you're using an inverted router in a table?

   Try taking most of the cut in one or two passes followed by a final light cut to clean up. Also check the grain direction of each piece relative to the cut and see how this affects the result. Slainte.

   RJFurniture

1. 
   NCLaquer | Nov 21, 2004 08:03pm | #2

   Good point about the grain direction.  I had forgotten to consider that.

   I figured bit sharpness could be a major factor, but the bits are brand new.  Granted, they are not top-of-the-line, but I would still expect them to hold-up through a few kitchen cabinets.

   Yes, I am using an inverted table... a benchdog pro top.

    

    

2. 
   Routerman | Nov 21, 2004 09:30pm | #3

   Some background & what to do about it.