Replies

1. 
   roc | Nov 15, 2011 07:24pm | #1

   >playwood<

   >reouble<

   What are these things you speak of ?

    

1. 
   AaronRosenthal | Nov 15, 2011 10:12pm | #2

   Join plywood to solid legs

   Ah, you caught my spelling mistake.

   It's a series of tables.

   The legs are maple and the skirting is 3/4" maple ply. while i'd like to use solid maple, this time I can't. I know there are other solutions, but I'm curious about the effect of loose tenons glued into the Plywood, and the long term life of the assembly vis-a-vis other joinery methods.

1. 
   roc | Nov 15, 2011 10:54pm | #3

   I am sure you will get better solutions here than I can provide

   I don't work with plywood much.  I am thinking since you will be doing more than one table that you will have trouble keeping the bits to cut the mortises in the plywood sharp.  The grit and glue in plywood tend to eat router bits.

   Not that I have ever done it but may be best to create a tenon on the ply by " cutting away everything that doesn't look like a tenon " and then you would just need to cut mortises in the solid wood legs.  Probably cut a groove ( longitudinal dado ) in the leg to make the fit up cleaner.

   This is unorthodox construction to be sure.

   Long term should be as good as loose tenons in solid wood.  Probably use epoxy into the plywood.  If a glue line in the ply happens to line up with the loose tenon face that would be less than the best situation.  The fresh glue should not stick to the old glue.  Epoxy probably will.  Worth a test here to verify that either way with both glues.

   Really, the long term glue/joinery problem comes from the solid wood loose tenon across the grain in the solid wood leg.  Ironically that is what is going to tear itself apart over time.

   I wonder if Norm Abram's New Yankee Work Shop online site has a video/project with construction along the lines of what you are making.  I am positive I have never seen him put loose tenons into plywood though.

   Probably best to back up and figure how to do this (financially etc. ) in solid wood.  At least for the aprons.

2. 
   swenson | Nov 16, 2011 08:53am | #5

   "I know there are other solutions,"

   Sounds like the "other solutions" might be the better way to go, such as leg apron brackets on hanger bolts.  Since wood movement is not a problem with plywood aprons and top, the brackets that have a flange for top attachment would solve both problems of attachment and leave you with tables that could be broken down for storage.

   EDIT:  I just noticed the topic in this forum on the Krenov music table in which they talk about plywood with an added veneer being used, where the veneer ended and allowed the protruding plywood to become a tennon.

2. 
   joinerswork | Nov 16, 2011 08:52am | #4

   Aaron,

   I'd simply cut tenons on the plywood aprons, but if you prefer loose tenons, don't see that they would be a problem either.  If you are concerned about the strength of the joint, the glue bond, or whatever, you might add glue blocks between the leg and apron on the inside.

   If your design allows, insetting (or off-setting) the aprons 1/8" or so below the legs' surface will eliminate having to flush-up the joint after assembly, with its risk of cutting thru the thin veneer face of the plywood.

   Ray

3. 
   bones | Nov 17, 2011 10:51am | #6

   I use the domino which in a sense is floating tenon.  You can use that joint if you wish with no issues.  I'm saying that not know what the design looks like.  Acutally if it's ply you won't have to deal with movement like solid wood.   I've used FT for ever love it.  

4. 
   forrestb | Nov 18, 2011 04:54pm | #7

   I think you're making it too complicated

   Why cut a mortise in the plywood for a loose tenon or cut the tenon on the plywood?  I would either attach the ply with Kreg screws or, if you have a right size bit, cut the mortise in the hardwood and glue the entire ply into that mortise.  If your best bit is a scosh too big, glue the correct size shims on the unseen side of the ply before inserting it.  In my opinion, any time that you reduce the ply thickness it loses too much strength.

   Forrest