A comprehensive educational community devoted to trim carpentry, finish carpentry and architectural millwork. Hosted by nationally recognized author and finish carpentry specialist Gary M. Katz.
 
     
  Jim Chestnut's Clam Clamps  
 
www.miterclamp.com
 
By now, most experienced carpenters have discovered that miters move. Miter movement means that every joint must be reinforced. Gluing casing miters, then nailing the casing to the wall and cross nailing the miters doesn't reinforce the miter joint. A glue joint will not reach it full strength unless the glue is assembled under pressure. Even a splined glue joint can fail if sufficient clamping pressure isn't applied before the glue sets. And spring clamps won't provide enough pressure to gain full glue strength.

 

 
Since I started installing casings wider than 2 1/2 in. (most new homes theses days are getting casings that begin at 3 1/2 in.), I've been using Clam Clamps to protect against miters opening after the heat comes on in the winter. These clamps are similar to the old Hartford cast iron miter clamps, but with a few twists.

 

 
Clam Clamps are manufactured in the U.S. from stainless steel and brass--and most of the machining is done by Jim, so they don't rust and they don't bleed onto your work, which is a huge deal. You can see the glue rising from the joint as the brass jaw squeezes the joint.
 
As with any joinery, the squeeze out must be removed thoroughly, especially on staingrade work.
 
A wet tooth brush works great for removing the glue even from deep-cut profiles. Keep a small tub of water nearby to rinse the brush, and change the water frequently so it's always clean. Wipe the workpiece and the clamp with a dry cloth to remove any remaining water. Since the clamp isn't made from iron, you don't have to worry about wiping rust onto your work piece.
 
For most materials, it isn't necessary to use all four nail points on each side of the clamp. I backed out two of the center points on all my clamps. The screws are easy to access with an allen wrench. There's one screw on the cam side that can only be removed when the cam is extended.
 
Jim thought of everything with these clamps, even storage for the screw/nails. Be sure you store each screw in the correct hole: the top middle screw goes in the top hole, the bottom middle screw goes in the bottom hole on each side of the cam. The tip of each screw is cut at a precise angle so the cam will pull the material toward the clamp. If you mix the screws up, you might end up with a cut that's not angled properly. For more information, and some pretty entertaining videos, visit Jim's website: www.miterclamp.com.
 
     
     
   
     
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