Making An Edge Clamp Clamps & Vises
Ready for another homemade clamp? This one is special: it’s used for clamping solid wood edge banding onto the edge of a plywood panel.
My upcoming drill press cabinet project will be made with plywood, banded with solid wood on the edge. Rather than glue and nail it on, as I’d normally do, I thought I would use edge clamps to glue it on.
So, I needed some edge clamps and I figured ten should be enough for the majority of my projects. A trip to my local hardware store to see what they had proved fruitless – none in stock. A trip to one of the “big box” stores had me leaving empty handed as well – they only had one on the shelf of reasonable quality. I looked online and came up with slim pickings – some really nice ones that cost more for one than I would want to pay for all ten.
With time ticking away, and thoughts of how I would make such a clamp taking root in my brain, I started in on a design. I tried a few different ideas, but settled on the one presented here. It’s relatively simple and not very difficult to build, using small pieces of wood and common, inexpensive hardware.
Here’s what I came up with:
To get started, the clamp screw and pad need to be made. I’m using 1/4″ threaded rod as the clamp screw, with nuts and washers to attach the clamp pad:
The two nuts closest to my thumb in the picture below will be tightened against each other later. The one on the other side of the washers will be inside the clamp pad, and to keep it in place on the end of the threaded rod, I pounded the end of the rod for an interference fit with the nut.
The belt and suspenders approach, I use polyurethane construction adhesive as insurance against the nut coming loose. The nut is threaded over the glue and tightened up to the end of the rod:
The two jam nuts are then threaded ahead, leaving enough space for the washers to turn freely.
The clamp pad is 1/2″ thick plywood. I cut two strips and drilled 1/2″ counterbores:
The fender washer is used to draw the circle on the pad.
Using my disk sander, I sanded them down to the lines:
To secure the pad to the washer, I’m using polyurethane construction adhesive. Epoxy would work here also.
This assembly is set aside to cure overnight. This is very important for slow set epoxy and construction adhesive, as they will not be anywhere near their full strength until the next day.
Meanwhile, I got started on the frame of the clamp. I’m using maple for this, and have cut all of the pieces to the right size:
These are joined with open mortise and tenon joints. I made the cuts with my dado blade on the table saw, using a jig to hold the parts securely as they were cut.
The clamp screw threads into a t-nut, and to make it work better in the 3/4″ thick stock, I clip two of the prongs off with my metal snips:
This leaves two prongs to dig into the wood, to stop it from turning.
For a nice tight fit, I measured the outer diameter of the t-nut and used a 19/64″ bit to drill the hole:
The vise is used to press the t-nut into the frame arm.
After all of the t-nuts are in, the clamp screw and pad are threaded into the frame arm:
The frame can now be glued together.
The clamp screw and pad hold the clamp on the panel, and to clamp the solid wood banding to the panel, I decided to use a cam clamp. The cam (cams, actually: there are two, one on each side of the frame) pushes against another pad, and that pad looks like this:
It fits between the arms of the frame and is free to move.
Before doing anything else, the clamp frame is sanded smooth and the corners rounded:
There is a pad on the other frame arm and it is glued in place.
Here I’m using the clamp as a clamp to clamp it while the glue dries.
To keep them compact, I made these clamps to fit a maximum thickness panel of 3/4″. I normally work with 3/4″ or 1/2″ thick sheet stock, so these clamps will be suitable for either thickness.
The attached SketchUp model has this limit slightly larger, with the maximum thickness of 1″. If an even greater capacity is needed, the parts can be scaled up.
For simplicity, the handle is formed by heating and bending the threaded rod over to 90 degrees:
This works well. The rod must be heated prior to bending, or it will break. I used a torch and got the area right where the bend will be red hot. After the bend was complete, but before it cooled, I hammered the bend with it flat on the anvil to relieve the stress, then cooled it with water.
The cam is laid out on 1/4″ plywood. There are two marks, one is the centre of the circle, and the other is the cam pivot point. The pivot point is 1/8″ closer to the edge of the circle and it is at this location on the cam where I’ll drill a 3/8″ hole:
I need a total of twenty of these cams for the ten clamps.
Drilled and cut out:
They were then sanded to the line on my disk sander.
The corresponding hole in the clamp is laid out and drilled:
The hole in the clamp is 25/64″, slightly larger than the 3/8″ dowel, which was cut with my dowel maker. This is to allow the cams to rotate easily. The cams are simply glued to the dowel, being careful not to get any on the clamp frame.
The cams may not look substantial, but they are very capable of applying adequate pressure for the task. I was somewhat concerned about the attachment to the dowel, thinking this will not be strong enough, that maybe it should be reinforced in some way. Early indications show that this is not the case, and that the cam to dowel glue joint is quite strong.
I made a simple rack to hang them on.
It was an interesting challenge to come up with a design that would meet my needs, yet still be relatively simple and easy to make. I now have ten very capable clamps to work with on other projects.