That’s Not a Holdfast
Christopher Schwarz and Lucy May are pleased to announce the newest addition to their family. Length: 18”. Weight: 9 lbs., 4 oz. Birth date: Feb. 15, 2012. Delivered by: Peter Ross, blacksmith and white smith.
After more than seven years of searching, I have finally found a bench holdfast that works effortlessly with a French-style 18th-century workbench. This gestation period for this project (longer than an elephant!) has been both frustrating and instructive. Here is the short version of the tale.
When I began getting seriously interested in workbenches, I began investigating and buying holdfasts – the primary workholding tool on a traditional bench. To my surprise, most holdfasts were crap. Breakable crap, actually. And I shattered quite a few gray iron versions in my early investigations.
Eventually I found holdfasts that worked, though they all seemed to lose their grip in thick workbench tops, especially anything thicker than 4”. Andre Roubo, the 18th-century French wunderkind, said benchtops should be 5” to 6” thick.
This didn’t make sense to me – until I realized how puny modern holdfasts were.
Here’s a translation of Roubo’s 18th-century writing on holdfasts:
Holdfasts are tools made of iron and are used to hold the work on the bench firmly and stably. They are ordinarily 18” to 20” and even 24” long in the shank; their thickness must be between 12 to 15 (1-1/16” to 1-5/16”) lines, and the curve of their paws is 9” to 10” long by around 10” high. They must be of very soft iron, forged in one piece so they don’t break. All their strength is in their head. That is why we will observe that from the head g to the paw k, they get thinner so that their extremity only has two lines (3/16”) of thickness at the most, which will make them more flexible and increase their pressure.
We must curve them so that when they are tightened they will only grip by the tip of the paw, because if they would carry more pressure in the middle they would ruin the work and hold less firmly (figure 4).
Yup. The holdfasts he is describing are as large as a newborn baby. They wouldn’t fit into a 3/4” hole in the top of a workbench. The holdfast Roubo is describing is just undeniably massive. How do I know this? I asked Peter Ross, the former blacksmith at Colonial Williamsburg, to make me one that was an exact copy of the one shown in Roubo’s books on woodworking.
It took months of research, planning, searching for materials, sketching and whacking, but Peter finally was able to fashion a wrought-iron holdfast that looks like it leaped straight from the pages of Roubo. He delivered it to me in February, but I’ve been too busy with other projects to tinker with it – until tonight.
The primary question at hand was: What diameter should the hole be in the benchtop for this holdfast? The shaft of the holdfast was about 1-5/16” in diameter where it pierced the bench. But I don’t have a bit that size. I have a 1-1/4” and 1-3/8”. So I drilled the smaller-diameter hole to start the process.
Of course, the holdfast got wedged into this too-small hole and wouldn’t come out. It was too tight.
After staring at the hole for a half hour, I decided to ream out the hole like a mortise through a chair seat. This made perfect sense in my head. The shaft of the holdfast is tapered. The mortise through a chair seat is tapered. When you drive a holdfast into a benchtop, it should tighten up like a leg into a chair seat.
So I fetched a tapered reamer and reamed out the hole in the benchtop. It tapers so it’s wider at the top and narrower at the bottom – just like the shaft of the holdfast.
After reaming, the huge holdfast dropped right into the hole with its pad just touching the bench. I took a mallet and tapped the holdfast. It immediately cinched down. Thrilled, I started securing thick pieces of work to the benchtop with the holdfast. It worked without complaint. It released without too much effort.
I don’t know if holes in old benches were tapered, but it sure worked for me.
If you are interested in having Peter Ross make you the ultimate holdfast, contact him through his web site. His work is beautiful, and extremely functional. I could not be happier with the tool – and the fact that a seven-year journey is at a clear end.
— Christopher Schwarz
If you want to read about benches and holdfasts, may I recommend my book: “Workbenches: From Design & Theory to Construction & Use.” It discusses all my theories on workbench design, and I hope to someday add a revised section on holdfasts with this big monster in it.