Tools of the Trade: The Holdfast
Now that we’ve covered sharpening and layout, one might think we’re ready to set to work, but first we must find a way to keep our workpiece from moving under our tools. For 18th-century woodworkers, this was done with a holdfast.
What is a Holdfast?
According to the 1765 Complete Dictionary of Arts and Sciences, a holdfast is “a tool used by joiners, carvers, &c. which goes through their benches, to hold fast such work as cannot be finished by its being held in the hand.” It’s effectively a roughly L-shaped piece of iron, which can clamp anything to the workbench. Moxon, in his Mechanick Exercises, illustrates one (labeled b) set in the workbench, resting and ready for use.
We use these almost every day in the Millwright shop, and they are certainly an essential piece of our tool kit. This is one that was made in the blacksmith shop at Newlin Grist Mill, based off of Moxon’s illustration.
How do they work?
Let’s first take a look at how Moxon explained their use--bear in mind, this is essentially a late 17th-century technical manual, so I’ve paraphrased what he said below the direct quote. Feel free to skip any and all of Moxon’s writing. I’ve included it as I feel it’s important to show where we’re getting this information, but I’ll always provide an explanation after.
[Holdfasts perform their] Office with the knock of an Hammer, or Mallet, upon the head of it; for the Beak of it, being made crooked downwards, the end of the Beak falling upon the flat of the Bench, keeps the head of the Hold-fast above the flat of the Bench, and the hole in the Bench the Shank is let into, being bored straight down, and wide enough to let the Hold-fast play a little, the head of the Hold-fast being [knocked], the point of the Beak throws the Shank a-slope in the hole in the Bench, and presses its back-side hard against the edge of the hole on the upper Superficies of the Bench, and its fore-side hard against the [opposite] side of the under Superficies of the Bench, and so by the point of the Beak the Shank of the Hold-fast is wedged between the upper edge, and its [opposite] edge of the round hole in the Bench.
Essentially the holdfast acts as a wedged clamp; when you strike the head with a mallet, it creates three points of pressure between it and the bench. The hole needs to be slightly wider than the shaft, so that there’s enough play for that wedging action to occur. I’ve included the image below to help explain. The arrows point to where the shaft and beak are pressing against the bench or workpiece.
How they work in practice:
At rest on the bench, you can see that the hole is just slightly larger than the diameter of the shaft, allowing for the wedging action to occur with just a quick mallet strike.
Here, the holdfast is clamped down on a piece (the smaller piece of pine is there as a sacrificial pad, the holdfast tends to leave dents on your workpiece if you’re not careful). You need a large mallet (like the one in the background) to really drive the holdfast home and get a good grip.
Here, the holdfast is clamped down on a doe’s foot (the board with a “v” notch cut into it), which allows you to hold a workpiece against a planing stop.
While essentially just a piece of bent iron, holdfasts are incredibly useful tools, allowing the worker to quickly and easily secure anything to their bench.
Again, I would normally invite everyone to come visit us in the Millwright Shop, but it’s currently closed due to COVID-19. We will be continuing to post here on the blog, and we’ll be doing more Facebook Live videos, so be sure to follow us on Facebook. Stay safe, and check back here next week!
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 Croker, Temple H., Williams, Thomas and Clarke, Samuel. The Complete Dictionary of Arts and Sciences Volume 2. London, 1765. Accessed April 30, 2020 “Hold-Fast,” Google E-book
 Joseph Moxon. Mechanick Exercises: Or, The Doctrine of Handy-works. London: D. Midwinter and T. Leigh, 1703. Accessed April 30th, 2020, Pg 68, Google E-Book
 Joseph Moxon. Mechanick Exercises: Or, The Doctrine of Handy-works. London: D. Midwinter and T. Leigh, 1703. Accessed April 30th, 2020, Pgs. 64-65, Google E-Book
Croker, Temple H., Williams, Thomas and Clarke, Samuel. The Complete Dictionary of Arts and Sciences Volume 2. London, 1765. Google E-book, accessed April 30, 2020, https://www.google.com/books/edition/The_Complete_Dictionary_of_Arts_and_Scie/uHNEAAAAcAAJ?hl=en&gbpv=0
Moxon, Joseph. Mechanick Exercises: Or, The Doctrine of Handy-works. London: D. Midwinter and T. Leigh, 1703. Google E-Book, accessed April 13, 2020, https://books.google.com/books?id=t_IRCzjTf08C&newbks=1&newbks_redir=0&dq=Joseph+Moxon&source=gbs_navlinks_s