Chris Schwarz's Blog

Questions on Glue, Nails and Drawbores

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.

– Christopher Schwarz

8 thoughts on “Questions on Glue, Nails and Drawbores

  1. William Duffield

    A cross-pein hammer is also a blacksmith’s tool, used for narrowing and spreading the end of piece of hot iron. See Fred Holder’s definitions, at http://www.fholder.com/Blacksmithing/article8.htm

    What you have there is a Warrington pattern hammer, and a quite elegant one, designed for the exact purpose you describe. It works just as well today for wire brads as it did for cut and forged nails.

    Peace,
    Sir William of the Cohansey

  2. Chris Somers

    Chris, thanks. Makes sense on the ball peen, as this also was my grandfather’s and he was a machinist in the US Navy, and a tool and die maker afterwards. -C

  3. Chris Somers

    Ah! Duh! Of course there was that article – but at the time, I really focused on the cut nails part of it; I ended up making the Dining Tray project from that issue. Now I’ll go back and absorb the part on hammers :) I actually do own a Maydole claw hammer that belonged to my Mom’s father. It’s just the head now, as the handle broke years ago.

    Follow-up Q, then: what’s the design reason for a "ball peen" hammer, then?

    -C

  4. Christopher Schwarz

    It’s the cross-pien (sometimes called the cross-pane or cross peen). It is used to start nails that you are pinching between your fingers.

    The form is more common in English tools than American ones. I wrote a good deal about hammers (and cut nails) in the issue with the Shaker Enfield Cabinet on the cover if you are interested.

    Chris

  5. Gary Roberts

    Chris

    On the topic of nails, there is to my mind a difference between wire nails and cut nails. Our familiar wire nails split the wood fibers whereas cut nails shear on their way through the wood. The use of wire nails is often the reason for the poor reputation of nails in general. Or at least that’s my take on it. I tend to look at things from the restorers viewpoint also. I’ve restored more pieces of furniture (or tools) than I have made them from scratch.

    A piece of furniture that lasted for 400 years could be one of those that was made correctly. We don’t see the ones that failed as they found their way to the garbage dump or the fireplace. Sort of like antique tools… they incredible failures are considered rare because no one wanted to buy one… or they where so delicate they self-destructed.

    And that is one nice hammer in the photo.

    Gary

  6. John Leko

    Reading question #3 about the soundness of drawboring, my first thought was of the original upon which Graham Blackburn’s "Bishop’s Throne" (or "Gothic Armchair" in his book "Furniture Design") was based. This chair, now in the Metropolitan Museum of Art, was made sometime in the fifteenth century constructed with drawborn frame and panel techniques. For this piece to hold up after 400 years, I would think would be a fairly convincing argument for the practice of drawboring.

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