The Holdfast
Holdfasts are an old form of clamp that work like magic. Hit them on the top and they clamp down on whats beneath them. Hit the back and they release. They are fast and flexible. I first obtained a pair when building my moxon vice and now they are my preferred work holding mechanism when I can make them work. Commonly available in 3/4 and 1 inch sizes, they turn any round dog hole into an awesome workholding device.
To give an idea of holding power, with 2 holdfasts holding my moxon to my bench, I can life myself up on the front jaws of the vice without it giving or moving, and I can drag my bench around by the moxon.
I glued a little bit of gasket liner material to the faces of mine. Stops them marking work pieces and makes them a little grippier. I use the Simon James holdfasts available from Workshop Heaven. They come with a drill bit for creating correctly sized dog holes, which is handy.
https://www.workshopheaven.com/simon-james-holdfasts-with-free-19mm-auger.html
(Disclaimer, I work for Union, Workshop Heaven is one of our official retailers). In the US, I hear very good things about the Gremercy holdfasts.
https://toolsforworkingwood.com/store/item/ms-holdfast.xx/holdfasts_by_gramercy_tools
I’d love to hear from someone who has tried out the Petrograd Toolworks holdfasts, because they look so damn pretty!
https://www.workshopheaven.com/petrograd-hand-forged-holdfast-type-1.html
There are a lot of articles insisting on minimum/maximum bench thicknesses for holdasts to work. If I believed them, then my bench is too thin, they work great for me. If in doubt, see if you can borrow some and try them out. You do need clearance underneath the bench for the posts to go, so if you have cabinets underneath your benchtop they may not be for you.
I only have a little clearance under my bench, so I often have to stick scrap on top of my work pieces to use my holdfasts. They are still useful as hell, but If I get around to building a new bench, getting full clearance for holdfasts will be a priority.
Finally, a common storage method is to drill holes in the right hand bench leg to store them. This has ht eadded use of allowing you to clamp one end of a long workpiece in your vice, and the far end can be pinned to the side of the bench with the holdfast.
Some useful links:
Wood by Wright on Holdfasts
https://www.youtube.com/watch?v=tYNwPt4GUqg
The Renaissance Woodworker reviews Holdfasts
https://www.renaissancewoodworker.com/holdfast-reviews/
iPlenty of good information on holdfasts in the Anarchist’s Workbench, which can be downloaded for free.
https://lostartpress.com/products/the-anarchists-workbench
The Simon James holdfasts, my own choice.
My Moxon vice being held down by holdfasts with the aid of a piece of scrap.
The Petrograd Toolworks holdfast
Gramercy Tools holdfasts
A facevise and holdfast cooperating to hold a long workpiece
