Lost Art Press

When Holdfast Holes Shrink

Posted on by Lost Art Press
You can open up your holdfast holes a tad with a slightly oversized bit.

After a few years of drying, my workbench’s benchtop shrank a bit. It’s not a big deal, but the drying process also shrank my 1” holdfast holes. And with a few of the holes it became difficult to insert the holdfast’s shaft.

There are a few ways to open up the holes a bit. Reaming them out with a 1″ drill bit and “wallering a tad” works, but it can take some effort to get the middle section of the hole to size. 

A second expensive-but-precise method is to use a tool called a “bridge reamer” or “car reamer.” These construction tools have a slight taper and are used to correct misaligned holes in steel construction and the like. These cost $100 or more, which is a lot for a single task.

The third option is to buy an inexpensive 1-1/16” drill bit such as this one. Before running this drill bit into your holes, I recommend you open up the top rim of the hole with a rasp so the bit won’t tear up your benchtop’s surface.

For drilling, use a corded drill with a side handle, especially if your benchtop is made of a hard wood. Yellow pine is especially tricky because of the differences in density between the earlywood and latewood. Take your time, don’t rush and you’ll get through it.

Holdfasts work best where there is a close fit between the shaft and the hole, so don’t over-do it.

— Christopher Schwarz

17 thoughts on “When Holdfast Holes Shrink”

    1. That’s exactly how I have started the holdfast and dog holes in the three benches I have made. It gets you down perfectly plumb for the first couple of inches to help guide the bit to finish it up through the rest of the thickness. It’s a bit slow, but after all the time spent making the bench, absolutely worth the extra time imo. Glad to know someone else thought the same way as me.

  4. Why go oversize? If the hole has shrunk why not just chase the hole with the 1″ bit that was used to drill the hole initially?

    1. I agree, it’s not clear to my why any solution other than this one would be required…

      There’s also the old “40 grit paper wrapped around a 3/4 dowel” trick that just never gets enough screen-time…

  5. I would not drill freehand from the top. I would fear, the drill catch wood and wander all over the top. So I would use my drill stand and fix it to the top. Or the Yankee Drill I bought because you told me they are the best. :o) (Just kidding, I sold that one because the “Flott” are better.)

    Cheers
    Pedder

    1. I have just looked up Flott drilling machines, they are very nice, but very expensive, I have an old Startrite Mercury bench/pillar drill, a bit old and worn to be honest.
      I would think the Flott are a bit over the top for hobby use given the price.
      I do admire the German engineering though.

    1. I wouldn’t have thought so, the hole may be too large to start with to be any use. After the shrinkage it still may not be optimal as shrinkage is not consistant around the holdfast hole. Timber shrinks very little in the length of a board but more so across the board so you may end up with an oval hole.

  9. That’s what I’ve done as well! Takes about 30 seconds of sanding to open up a dog hole.

  11. In my experience holes in wood only go one way, and that is larger. Dog holes, screw and nail holes…when the wood moves or shrinks holes get bigger.

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