Saturday, May 31, 2014

Severed Tenon Repair: Part Two, Removing the Nail


There's the bugger.
Part One can be found here.

Now that a new tenon has been grafted, we turn our attention to the nailed mortise. Here is the culprit. The nail was driven into the tenon presumably during assembly (I assume because it was painted over). The nail faithfully held that tenon in place even when the stretcher was dissociated. Thanks, nail.

Nail removal is frustrating to me because there is no way I am aware of to remove a nail that has been hammered flush to the surface without further marring the surface. You’ve got to get under the head of the nail somehow. With this in mind we look for the least intrusive way to pull that nail out.


In my experience, I have found this nail puller from Lee Valley to leave a smaller footprint than others. In fact, I even ground the jaws narrower when I received it. You can see I made sure it was slightly smaller than my 1/8” chisel. 



I start by carving a small groove on opposite sides of the nail running with the grain. Don’t make it look nice and straight or abruptly end the groove. Visual regularity of fills only makes them stand out more in the end. You want it irregular because you eye will not detect it as easily. The priority here is to make sure you are deep enough and not longer than you need. 


Start by slipping the jaws underneath the head of the nail. You then may give a gentle strike on the top of the puller to get a grip on it. Hold the puller in place and hook the hammer onto the puller. There are two points on the puller which you could connect your hammer to. The lower one I am using here offers more control. When leverage is applied the jaws pinch shut. Note that the puller’s foot placed against the piece is covered in leather so as not to dent the surface. 


I know. It's not pretty.

Pull gently. Don’t let the hammer slip out once the nail comes free. On really long nails, I use pincers to incrementally pull it out of the hole once the head is above the surface. Pincers are less cumbersome and don’t have the aggressiveness needed in the first stage of nail removal. Just don’t pry directly on the surface. Get something protective between the piece and tool.

The mortise with the tenon fragments are cleared (which I now suppose I should have photographed as well) with an undersized drill bit, leaving a narrow ring of tenon fragment inside the hole. I then use a small carving gouge to separate the tenon pieces from the wall of the mortise. Try not to gouge the wall of the mortise. With a little pressure the tenon pieces usually pop right out of the mortise.



I finish sizing the tenon to fit with chisels, rasp, sandpaper, etc. The fit should be snug but not a bear to get in. If you tilt the piece down and the stretcher doesn’t fall out of the mortise by its own weight, you’re good to go.


Here’s the hole filled and inpainted. I often in these cases fill with a wax stick and inpaint with shellac. It is easily removable in the future and is very easy to execute. An alternative is Timber Mate Wood Filler. I use that stuff a lot too as it is also easily reversible.

4 comments:

  1. Not sure that it would have worked in this instance or met your conservancy standards but I probably would have ground off the head with a dremel and tried to push the nail though with another longer nail and pull out via the exit side. Excellent work here as always.

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    1. Thanks JMAW! I do that sometimes but there is a risk of blow out on the exit side. In this case the exit side is the outside of the leg (the nail was driven in from the inside of the chair). I also have sometimes had problems driving the nails straight and keeping the driving nail on the old nail's shank. I've ended up making more of a mess because once I got it part of the way, if it doesn't work out, then it's a really big mess to dig it out. All things considered I find this method guaranteed and the risks of driving nails too great to be routinely utilized. If I know I have a large nail in small stock (so I know for sure I can drive it through) where the exit side is not normally visible then I attempt to drive it through. Thanks for sharing your thoughts!

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  2. Josh, I am in awe of your restoration skills. Would it have been possible to drill the broken tenon with a small bit on either side of the nail?

    Then pick away the remaining fibers of the tenon until the nail is accessible. Once the nail is exposed, grab it with needle nose pliers and push it out from the inside.

    I think this would minimize the repairs around the nail head.

    Steve

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    1. Steve,

      Thanks for your comment! I love hearing from readers.

      To answer your question...Often the only way to get it out is pull it. Driving it through the other side causes breakout which makes it two places to repair... remember there still is material missing from the nail head being driven in. Additionally, filling and inpainting round or square fills are much more difficult than fills tapering with the grain (think: skinny football). This is one of those things I would have to show someone in person. I've tried it all and this works the best for me. And this is coming from someone who goes to far lengths to preserve as much original material as possible.

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