Replies

1. 
   hammer1 | Nov 11, 2004 08:34am | #1

   You can always use a template guide instead of a pattern bit with bearing. With the template guide you can use a core box bit that will give you radius corners, use any bit you want, at any depth.

   Beat it to fit / Paint it to match

2. 
   CharlieP | Nov 11, 2004 04:40pm | #2

   The bowl cutting bit creates a cut with rounded bottom corners, a dado cleanout bit has square bottom corners.

   A pattern bit, such as your book apparently describes, has a bearing on the shaft so that a pattern is clamped or taped to the wood on the "router side" of your work piece.  If the bit is "too long" as you describe, the pattern must be thicker or must be spaced away from the work.  I have a pattern used this way that has to be 3/4 inch plywood rather than the 1/4 or 1/2 inch you would expect to use, so that the hole I am routing is not too deep.  Since the bearing that follows the pattern is normally the same diameter as the bit, the pattern is the same size as the work.  Since the bearing and cutter are on the same shaft, they remain perfectly aligned.

   If you don't have a pattern bit, or cannot find one that you like, then a collar can be attached to the router, surrounding the bit.  The collar is typically just under 1/4 inch high, so your pattern can be almost any thickness, 1/4 inch or more.  But the collar is larger than the bit, so the size of the pattern must be adjusted for the differences.  The collars are pretty accurate on most routers, but there is also the issue that the bit may not be perfectly centered in the collar.

   ________________________
   Charlie Plesums  Austin, Texas
   http://www.plesums.com/wood

3. 
   johnsp | Nov 16, 2004 03:17am | #3

   I believe thay may be referring to a bit called a "tray bit". It cuts a flat bottomed hole with rounded edges. Freud makes such a bit, as do some other companies. I found mine at woodworker.com, search under tray bit. I'm sure other companies have them too, but coundn't find one at woodcraft.