Replies

1. 
   WayneL5 | Mar 26, 2005 09:20pm | #1

   You'd use a down spiral in any situation in which lifting up would tend to tear at the surface.  Some examples include wood that splinters easily, veneer, and laminate.  Usually such bits are used along an edge so chips wouldn't collect.

2. 
   charlesm | Mar 29, 2005 03:17pm | #2

   You use a down spiral when surface finish is important and chip clearance isn't an issue (such as for shallow cuts or when inverted in a table). The up spiral is definitely superior for chip clearance and for plunge cutting but will splinter delicate material like veneered plywood.

   Charles M
   Freud America, Inc.
1. 
   Ricks503 | Apr 07, 2005 06:50pm | #3

   If you use a router table, a down spiral pulls the cuttings up away from the router to wher they can be removed by dust collection.

    

1. 
   charlesm | Apr 07, 2005 07:24pm | #4

   Rick,That's a good point and it's true for through cuts. For grooving/dadoes on the router table gravity will pull the chips out and reduce buildup of chips in the cut.Charles M
   Freud America, Inc.

2. 
   BArnold | Apr 08, 2005 08:14pm | #5

   "If you use a router table, a down spiral pulls the cuttings up away from the router to wher they can be removed by dust collection."

   Actually, just the opposite is true.  The terms 'upcut spiral' and 'downcut spiral' refer to the direction of the slicing force when a router is hand-held.

   In the hand-held mode, the downcut spiral forces the chips away from the router and makes a cleaner surface cut.  An upcut spiral will pull chips out of a cut like a mortise toward the router motor.

   When the router is mounted in a table, it is 'upside-down' to its 'normal' configuration.  Therefore, an upcut spiral bit will pull chips into the table allowing for dust collection to work better.  A downcut spiral bit in a table would force the chips upward toward the operator.

   Regards,

   Bill Arnold - Custom Woodcrafting Click Here if you're interested in a good,inexpensive website host.

   Food for Thought: The Ark was built by amateurs; the Titanic by professionals.