Adrian Mariano writes: I just watched your DVD (“Forgotten Hand Tools” from Lie-Nielsen Toolworks) in which you advocate the use of nails and drawbores to overcome the flaws in the glue. And there were a couple things I was wondering about.
One is the question of glue longevity. If I glue together a tabletop with hide glue will it fall apart in 100 years? Two hundred? Or do glue joints only fail if they are stressed? (Presumably the side-grain-to-side-grain joint of a tabletop creates very little stress in the joint.) I haven’t heard of people, say, putting together tabletops using sliding dovetails to ensure strength.
Answer: Any good glue joint can last centuries. Its life will be shortened by moisture, heat and stress. Moisture on a tabletop is a common factor. Heat can be. And tabletop joints are stressed at the ends by the migration of moisture through the end grain — that’s why antique tops split on the ends typically.
Breadboard ends and cross-battens are typical and historically correct methods of helping to keep a top together.
Question No. 2: Why are nails better than screws? I haven’t tried to use nails in cabinetry, but I’ve tried to use them in carpentry and my experience has led me to hate nails and to use screws instead whenever possible. They bend over, they split the work (sometimes even with a pilot hold), and hammering them in can be very loud, and it subjects the work to stresses, possibly causing parts to move or shift. Maybe a screw head is harder to hide than a nail head. But is there some other reason to prefer nails?
Answer: Hmmm. I don’t consider nails to be better than screws for all occasions. But there are some advantages to using nails at times. Nails will bend to accommodate wood movement. Screws won’t bend. They’ll split the work. Nails are smaller and can be used in places that screws would be ugly (nailing on face frames and moulding). They are inserted faster than screws (removing them sure is slower!). And they can be historically correct in pieces, which can be important to some woodworkers (such as myself).
Question No. 3: Another thing I was wondering about is that I saw an article a few months ago (which, alas, I have not been able to find again). This was an article by Bob Flexner on furniture repair and restoration in which he claims that the use of metal fasteners guarantees problems down the road, and I recall that he said pinning a mortise-and-tenon joint would cause it to split eventually. He seems almost directly in opposition to the use of nails and the drawbore, and justifies his position based on the types of damage he sees in old furniture. Do you have any thoughts on how to reconcile this with your claims in the DVD?
Answer: Bob is one of the people I highly respect in this business. He also comes at this problem from a restorer’s viewpoint. It’s more difficult for him to disassemble a joint pinned with a mechanical fastener, be it a wooden or metal one. His comment was aimed also at people who nail a loose joint instead of disassembling it and regluing. That is indeed bad practice.
I don’t think a pinned joint guarantees joint failure at all. I have seen pinned joints that are 400 years old and are completely sound. Drawboring is a sound practice for certain kinds of applications where mechanical strength is key or you are working under unusual conditions (wet wood, long spans and no clamps) or you are striving for historical accuracy.