Replies

1. 
   forrestb | Jan 12, 2014 07:56pm | #1

   I use on one side

   Since the purpose is to flatten the surface, it seems to me that you want a flat surface underneath.  I had a 32 inch diamneter lazy susan that I built for my wife and I used cauls only on one side.  The other side was jointed thick boards that supported the cauls.

   Don't know if that is 'right' but it worked for me,  That table was flat and needed only finish sanding.

   Forrest

2. 
   Rob_Sp | Jan 15, 2014 08:17pm | #2

   Mill your lumber flat and square

   Use quality I beam clamps. And you will not need cauls 

3. 
   Rob_Sp | Jan 15, 2014 08:17pm | #3

   Mill your lumber flat and square

   Use quality I beam clamps. And you will not need cauls 

4. 
   RickL | Jan 20, 2014 02:09am | #4

   Cambered cauls...

   Been using them for 40 years in small custom shops and my home shop.  Have always milled the wood to finish thickness and edge glued the boards  in one shot without biscuits or dowels single handed.   Top and bottom cauls have crowns and are spaced every 18".  When the cauls are removed I only have to scape the glue beads and sand the mill marks.  With cauls you can use bent twisted pipe clamps and get better results than Jorgensen I-beam bar clamps. Curved cauls are the basics of a veneer press. I typically use 1/8" crown on a four foot caul.