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For my first woodworking project I'd like to build a polygon shaped, heavy duty work desk. I've modeled the desk with all necessary pieces in Fusion 360. I wanted my mortise and tenon joints connecting 100x60mm rails to 100x100mm legs to have 50mm deep tenons with pegs for strength, and my 90 degree joints accommodate this. Unfortunately due to the polygon with 135 degree angles, I need to adjust my interior joints to 30mm deep tenons without pegs. Making matters worse, I don't have room for the mortise on the outside 135 degree legs so I can add additional rails where the table top sections join.

Will these joints be strong enough?

I've linked to the 3D model in the text, but for those unable to load here are some renders:

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rcampbell
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    Can you post a pic? It's hard (for me, at least) to have an opinion based on a text description. – Aloysius Defenestrate Dec 03 '17 at 02:07
  • My text contains a number of links to full 3D models you can interact with. – rcampbell Dec 03 '17 at 10:32
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    I can't get the graphics to load but as a rule anything put together with M&T joints of reasonable scale to the overall piece will be more than strong enough for service, assuming they are cut well and glued together properly naturally (although this is much less vital when pegging). Short tenons, called stub tenons. are quite commonly used where needed and they don't significantly undermine strength in moderation, as part of an overall structure where there are other joints. – Graphus Dec 03 '17 at 12:42
  • @Graphus - Thank you, that makes me feel better about the "stub" tenons. I've added renders of some of the key pieces. – rcampbell Dec 03 '17 at 13:25
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    Sweet renders! Now that I can see it, yeah, that'll be more than strong enough. People put together benches and work tables of similar kinds intended for heavy use (e.g. for engine work) without any proper joinery, using for example pocket screws or simple metal brackets/strapping to hold the leg assemblies together and have no issues with how they hold up to both heavy static loading and occasional dynamic loading. – Graphus Dec 03 '17 at 14:14
  • Agree with Graphus... – Aloysius Defenestrate Dec 03 '17 at 21:57
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    Side note, if your top is lumber (not plywood), you'll want to let it float a little to allow for seasonal expansion/contraction. Would suggest biscuits/dominos to help hold your joints together regardless of the material. – Aloysius Defenestrate Dec 04 '17 at 01:09

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This design is plenty stout and has lots of extra strength built in to cope with material inconsistency and intermittent stresses put upon it. Those are excellently beefy pegged mortise and tenon joints in good proportion to the project. This method of joinery has been the gold standard for hundreds of years of solid furniture making and if built with even a minimum of care, this desk will likely outlive you and some number of descendants.

Otto
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