Replies

1. 
   AlanWS | Oct 18, 2005 11:01pm | #1

   It does not sound like a good idea to me. Tenons are there for strength, primarily strength in tension, but bending as well once the joint begins to loosen. MDF is even and smooth, but not particularly strong. A wood tenon is likely to fail at the glue joint long before it would break the wood, but MDF is likely weak enough that it would fail by tearing apart. One of the big advantages of M&T over enough biscuits to give the same breaking strength, is that M&T fail gradually, allowing repair before it's too late, while biscuits fail catastrophically. I would think MDF tenons would resemble biscuits in that regard, but might be weaker.

   Edit: Comments on joint strength are based on a FWW article reprinted here: http://www.taunton.com/store/pages/070479.asp

   
   

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   Edited 10/18/2005 4:04 pm by AlanWS

1. 
   marc517 | Oct 19, 2005 03:52am | #5

   Thanks for your input Alan......I'm definitley going to run real wood tenons for sure now, I'd rather be safe than sorry later on...Thanks again for the reply.....

    

   Take care,

   -marc

2. 
   sapwood | Oct 18, 2005 11:59pm | #2

   not a good idea at all

1. 
   marc517 | Oct 19, 2005 03:54am | #6

   Thanks for the input, and I'm going to skip the MDF Idea for sure.....

3. 
   RickL | Oct 19, 2005 01:29am | #3

   Absolutely not a good idea. Make up a sample tenon of wood and mdf and stick it in a vise with half of each exposed and hit with a hammer. The mdf will break easily so imagine what would happen with your door. Been using loose tenons and slot mortisers for over 20 years and think it's the best joints you can use for many applications.

1. 
   marc517 | Oct 19, 2005 03:58am | #7

   Thanks for your advice......I actually did glue up some pieces last night before I left the shop and performed the ole hammer test this morning and did find that the wood tenon was quite  stronger and ultimatley gonna just forget about the mdf idea...again, thanks for the input........

    

   -marc

4. 
   BillLindau | Oct 19, 2005 01:34am | #4

   Marc, I've  used 3/4" plywood as a loose tenon. But MDF doesn't have any long grain, no tensil strength, it would seem, although this is just a guess. Bill

5. 
   Ridge | Oct 19, 2005 04:12am | #8

   It is always difficult to be sure from a photo, but this does not appear to be a nut tree.  It appears to be in the white oak family, possibly a chestnut oak.  Does the side grain on the split piece have medulary rays visable?  Also, fresh cut oak has an unmistakable acid (vinegar like) odor.