Get a quick, firm and fuss-free hold on workpieces on your work table or workbench! It is easy to do with these types of clamps, known generally as holdfasts. They insert into a round hole in the work surface, and with a thumbscrew or a simple tap with a hammer or mallet will hold a plank, jig, or various table-top tools and stands, just about anything, as if it had been nailed in place.
These kind of clamps are produced in Canada and the USA. Because they are made mostly for the American market, they are sized in inches. One inch equals 25.4 mm. They are designed to be inserted into holes with a diameter of 3/4 inch. 3/4 inch is 19.05 mm. But it doesn’t really matter whether you make your holes 19 mm or take the trouble to find a 3/4 inch drill bit: the tiny difference in diameter will make no difference at all when using these bench clamps. All of these tools are made slightly under diameter so they will not bind in the holes unnecessarily in use or if the benchtop swells with changes in humidity. Drill bits at 19 mm and 3/4 inch can be found on our drill bit pages. Drill Bit Pages.
We have often been asked if these holddowns and holdfasts will also work in 20 mm holes. I will say here again clearly, no! It is a bad idea to use over-size holes as the contact between the shaft of the clamps and the bench top is much reduced if there is too much play in the holes. This both reduces the available clamping pressure that is possible, and will over time damage the edges of the holes, decreasing still further the holding power of the clamps.
JUUMA Holdfast for round 3/4 Inch (19 mm) Holes
This solid, cast iron holdfast is essential for any workbench. The large, ergonomic grip is made from two-component plastic. It easily yields high clamping pressure with just a few turns. The large rubber pressure plate ensures non-marring clamping of the workpiece and has a diameter of 44 mm. The fluted shaft securely fits into any 19 mm i.e. ¾ inch hole, which has become a standardized size due to wide-spread availability. It is galvanized and has a length of 155 mm. Clamping depth is 125 mm, measured from the middle of the pressure plate to the inner leg of the shaft. Maximum working height is 115 mm, when shaft immersed 60 mm into hole. Great value for money!
Weight 750 g.
Dog Hole Bushing for 3/4 Inch Holes
These 19 mm hardened steel bushings help you make an accurate dog-hole drilling guide using any 38 mm (1-1/2 inch) thick board.
Knurling on the bushing provides a mechanical lock when installed in a 25 mm hole, and a projecting rim ensures that it rests perpendicular to the jig's surface.
If you don't already have a bit in the required size, we offer a 25 mm forstner bit that is 90 mm long overall.
For drilling the dog holes, we offer 3/4 Inch (19 mm) drill bits that are 190 mm long overall, enough to go through the jig and a thick bench top. The lipped brad-point style scores the perimeter of the hole for clean entry and smooth sidewalls.