Replies

1. 
   JohnWW | Oct 29, 2009 03:24am | #1

   Long and deep open mortises have a habit of closing up, or occasionally bowing out, from stress release and wood movement, this is why long mortises, in addition to being haunched, are usually broken up into two shorter mortises. Now that you have the problem you might try the following:

   The easiest thing to try is to increase or decrease the wood's moisture content. Wood more typically dries out when stored indoors so adding moisture is probably the direction to go in. If the wood could have gained moisture, by being stored someplace damp, try to dry it out. It will take several days to a number of weeks for the wood to gain or lose a significant amount of moisture so you will have to be patient. You can try to use a pair of fox wedges to gently push the mortise open as the wood gains or loses moisture, but the moisture change is what will make the real difference.

   You could of course simply thin down the tenons to fit, but you will find that the outside of the stiles have sunk in over the mortises and this might be apparent in the finished door, so expanding the slots is the better solution. Also the inside faces of the mortises are bowed so the fitting would be tricky. You could also plane down the components to eliminate the dishing and then clean up the mortises until they are again wide enough to fit the tenons.

   Once a joint is fitted always try to get to the final permanent assembly as quickly as possible because, as you have discovered, the fits can only get worse the longer the parts sit around.

   John White
   Shop Manager for FWW Magazine, 1998 to 2007
2. 
   Jfrostjr | Oct 29, 2009 04:42pm | #2

   Another approach to a fix your problem if John's drying attack doesn't work would involve carefully hand-fitting a filler plug for the mortise.

   Glue it in place and machine a new, properly sized (and shaped) mortise.

   Frosty

   “If you put the federal government in charge of the Sahara Desert,
   in 5 years there’d be a shortage of sand.”

   Milton Friedman

3. 
   joinerswork | Oct 29, 2009 04:55pm | #3

   jpari,

   I believe I'd take this opportunity to divide that long mortise into two smaller ones.  Cut a filler plug or web 1 1/2" or so long by 3" wide  by 1/2" thick to insert into the middle of the mortise, spreading its cheeks in the process.  Be sure and clamp the end of the stile, while inserting the glue coated plug, to keep it from splitting.  Trim the ends of the web true when the glue dries, and fork the tenon of the rail to fit.  Expect some re- fitting of the tenon cheeks at any rate.  A well-fitting mortise and tenon joint doesn't necessarliy stay that way if it isn't put together right away.

   Ray