Tenon length

[Philip Berman]

hi -

I'm building an outdoor serving table using meranti. Legs are 3x3 posts with rails approx. 4.5" wide. Overall size of the piece is to be 72"longx24"deepX34"tall. The rails are 3/4 or 7/8 thick. The top is a piece of 3/4"thick granite. How long must the tenons into the legs be? I'm trying to bang this out quickly and so would like to do the mortises with the router, but I can only go 1" deep with the bit I currently have. Would this be adequate? I can't envision this thing being moved around due to the weight and because it's been sized for a specific location, so for the most part, the stress will be downward more than sideways as in dragging the table.

Thanks for the suggestions.

Phil

[Jamie Buxton]

Yes, tenons that are an inch long should do you just fine, presuming they're a nice tight fit. If you're routing the mortises, you should be able to get a nice fit. You'll have a good big glue area, and the forces on it will be in shear.

Do use an outdoor glue. I'd use epoxy. Many folks use Titebond II or III and say that it works.

[Frank Drew]

Phil

For this table I'd be happier with a longer tenon, more like 2+" than 1", but in any case both tables and chairs really benefit from corner blocking - mitered blocks glued and screwed to the rails on each side of the legs.

[Cliff Rohrabacher]

out of doors?
I'd make 'em bigger than one inch.

Take a warning about epoxy on an out-of-door dark lumber piece of furniture unless it will spend its life in the shade. Don't use it for the same reason you don't use epoxy on the wood mast of a sail boat that may possibly sail tropical waters. The heat on the dark wood will soften the epoxy which will go to pieces rather quickly once temps get past 120 F. This causes the masts made by epoxy gluing to delaminate. The hot sun won't help out door furniture glue joints either.

Consider using resorcinol glue.
The hot sun on dark wood won't cause resorcinol glue any issues at all. It can take boiling just fine.

Resorcinol has two drawbacks (only two). One is temperature. Your shop and the lumber all must be at some temperature around 70 Deg F to use it and the other is pressure of clamping and tightness of the joints. The glue needs R-E-A-L-L-Y tight joints and high clamping pressures. If you can bring that to the party, you are golden.


I have glued Adirondack chairs with Titebond III painted 'em white and left 'em out all year in the sun and snow. They are holding up well some two years later.

[Frank Drew]

The heat on the dark wood will soften the epoxy...

Interesting; I didn't know that about expoxy, Cliff.

If the table is outdoors but for the most part out of the weather I'd also consider using brown glue (Weldwood's Plastic Resin, for example.)

[Philip Berman]

for sharing your thoughts on this. Went with 2" tenons afterall.

Phil