Drawbore M/T
By all means pin your tenons...
especially on a bed that'll get bounced on....those cross grain glue joints will eventually fail in a generation of so and a good drawbore M/T will allow that piece continued use to your grandchildren or great grandchildren without damage.
The "modern glues" logic applies well to short-lived kitchen cabinets but not heirlooms....
all cross grain glue joints will eventually fail....flexible epoxied joints may not, but just try to repair them one day without total destruction of the joint. Less-flexible PVA's and polys certainly
will fail eventually in a cross grain application.
Drawbore the tenons.
Dry assemble the joint....drill through the cheek until the drill bit just puts a mark on the tenon....disassemble....drill thru the tenon a 32nd-16th or so
inboard of the mark toward the tenon shoulder....then drill thru the other mortise cheek without the tenon installed.
Use a speed square to line up your drill instead of the drill press. How far into the joint do you drill? Depends on the size of the tenon and the thickness of the mortise cheeks that'll take the pressure of the drawbore. Try one first on similar-sized scraps if you are unsure. 2" thick maple legs like on my hunt table below allow the pinhole to be as close as 3/16" from the tenon shoulder. When in doubt, give yourself a quarter inch or more...it isn’t critical if you can drill a plumb hole.
Then point some dowels...glue and assemble the joint...use glue as lube for your pointed dowel and drive it through. Use small size dowels, allowing room for a descendant to make a repair one day using a dowel of slightly larger size.
Simple, fast, and pulls the joint up so tight you may not even need to clamp it.
Disassembly for repair one day? Steam the dickens out of the joint and drive the pin through with steel punches. Use a matching size punch to break the hot dowel free, then switch to a smaller punch to drive it through the offset drawbore holes.
Few joints are stronger....note the untrimmed pointed dowels on the inside of the legs about a quarter inch inboard of the tenon shoulder....each leg-rail joint has two drawbored M/T:
http://pic3.picturetrail.com/VOL12/1...5/36332508.jpg
You can also see the drawbore pins in this maple pedestal buffer stand that have withstood almost 3 decades of serious vibration successfully with casein resin glue.
http://pic3.picturetrail.com/VOL12/1...7/41748405.jpg
Quote:
Originally posted by....:
Thanks for the advice and vote of confidence. Good example given!
One other concern I have is having the pins break, crack, splinter, or mushroom while hammering them into the drawnbore tenon. Any tricks I can use; especially if I go with a small diameter pin (1/4" or 3.8" dowel)?
Don't use anything larger than a quarter inch in your dowels or a 16th in your offset and the pointed dowels lubed with your glue will drive in without splintering. Let them soak in the glue for a while to soften them if you are concerned about it. If one breaks, then drive it back out before the glue cures as I describe above.
I allow a 3-4 inch pin for a 2" joint to allow for pointing and any mushrooming...simply cut it flush when cured.
Also notice in my hunt table pic...I left those dowels untrimmed on the inside for a reason...so there's no doubt in the restorer's mind how the joint was made and they can be broken free easily one day for a repair.
Simple but practically bulletproof joints.
Quote:
Originally posted by....:
Ok, so I am also in the middle of a bed project. I have read and learned lots in this post about pinning tenons. Very informative, what I also want to ask is it ok to just put in a screw and the plug it? Will this do the same thing?
I wouldn't bother with screws:
1) They can't cleanly serve the function of drawing the joint tight....the main reason for pins in hard-used furniture, IMO.
2) A bunged one may confuse a restorer some day and the joint will be wrecked trying to dismantle it.
3) They make my teeth itch
I like drawbores even better than sliding dovetails in bed joints because when 2-4 children vault over the footboard, hopping on to bounce, every joint works in conjunction with the rest to resist the racking stresses.
Picture how the joints break down from that over time....one glue joint fails and the racking stress becomes proportionally more severe on the other joints...which fail in turn. If the failures go unnoticed or ignored for a few years, the bed may be used until it literally falls apart, by which time there may be such major damage to the joints that it will be discarded rather than restored.
Most of what my traditional joinery originally designed for weaker glues does is better the odds that a restorer will save the piece one day after decades of abuse....both because the joints will stand the stress without glue and that they are of such quality that the piece will be worthy of saving in the first place.
