Chris Schwarz's Blog

About Holes and Cracks and Benches

Question: A couple of questions regards to my Roubo bench project:
 
1. Regarding laminating the top: I’m not the best laminator in the world. I
have about a dozen small cracks on both top and bottom of the Southern
yellow pine top. Tried filling them first with Titebond III, then Hot Stuff
Special T (sold at Lee Valley), and the Veritas cabinetmaker’s glue. Mixed
results from all three products. Most common result is a crack that’s mostly
filled with small “swiss cheese” type holes in the dried glue. Can you
recommend anything for this dilemma that looks good once planed down?
 
2. Phil Koontz holdfast diameters: Just ordered the large holdfasts from
Phil Koontz and his (Jake) the Russian buddy. According to your article,
these work best in a 11/16″ diameter hole. According to one of Phil’s galoot
bulletin board messages, he recommends the large holdfasts go in a 3/4″
hole, and the regular-sized holdfast in a 11/16″ hole. Before drilling, I
called Phil. His bottom line is that hole size doesn’t matter; that if I use
a 11/16″ hole, I’ll wind up knocking the holdfast around a bit, till the wear
and tear of the hole loosens it up a bit. What say you?
 
Thanks again for your helpful advice, and the tremendous work you and your
team do at Woodworking Magazine! I’ll be in Afghanistan for the next year
(starting in January , I’m an Army Colonel ,trying to get this project
completed!), and won’t be able to do much woodworking, but know that your
magazine will keep me informed and entertained.


Mark in La Crosse, Wisconsin


Answer: On my first workbench I had an area where the top either delaminated or I didn’t fit the parts well. I filled the area with epoxy (you can buy it in a variety of viscosities). Once the epoxy dries, you can plane it flush with a block plane.

Here are some other strategies:

If the crack is too serious for epoxy, I’d glue a wedge in there. Or, if the crack is irregular, I’d run a handsaw in the split and then glue a wedge in there.

If the crack is too serious for a wedge, I saw the top apart at the lamination, dress the two edges and glue them back together.

Or (final option) accept the crack as a lesson learned on a workbench instead of a lesson learned it on a highboy. Every time you see the crack, you’ll be reminded to do better.

On Phil’s holdfasts: You need a tight hole on a thick workbench or one with softwood. If your bench is a la Roubo (4″ thick), then use the tight hole. If your benchtop is more … uh… modern in thickness (2-3/4″ or so and made from beech) then 3/4″ will work.

Here’s my best advice on that: Make a sample hole in a sample chunk that matches your benchtop in species and thickness. Clamp the chunk in a vise and try out the holdfasts.

But don’t worry too much. Phil’s holdfasts work great in almost any conditions.

Good luck overseas!

Christopher Schwarz

One thought on “About Holes and Cracks and Benches

  1. Alan DuBoff

    In theory, the size of the hole for the holdfast doesn’t matter, in the sense that the diameter of the holdfast is a variable.

    It should be possible to make any size holdfast for any given hole. By saying you need a tight hole on a thicker workbench would imply that the holdfast needs to be a slightly larger diameter, for the same size hole of a thinner benchtop.

    Anyway, it would appear that if you had a holdfast which was 1/16" larger in diameter, it would fit a 3/4" hole on a thicker benchtop.

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