If anyone remembers my festival of shop made bar clamps from a few years ago, you may be surprised to learn that they weren’t perfect after all. True I’ve used them as much as I could over the intervening time, but I was always contemplating on how to make them better. I even came out with an improved clamp a little while ago, but it too was not quite there.
My improved clamp sports a stronger screw (3/8 in. instead of 1/4 in.) and the movable stop is much better, depending on detents and an arm instead of a bolt in a hole and some good wishes. I don’t like the handle for the screw, but we’ll deal with that somewhere in the future.
So if for some reason you’ve made my original bar clamps, here’s how to make them much better.
[Below] My original clamp had a movable stop that held its position via a bolt which went through a hole in the bar. The probem is that the stop head wobbled and sometimes glue ups were not held as tight as I would like. The object being clamped would also ride up off the bar.
[Below] So we take that stop off, salvage the eye-bolt, washer and T nut and chuck it away.
[Below] We’re going to replace it with a thinner, triangular black with metal arms. Here’s what I used.
[Below] And here’s how it all goes together.
[Below] Now we’re going to make some alterations to the bar of the clamp. This first step isn’t REALLY necessary, but since I did this to most of my other clamps, I’ll show it here as well. I’m marking for a hole into which a dowel will be glued. The dowel will keep the new movable stop from sliding right off the bar onto the floor whenever you tilt it the wrong direction. (If you like when that happens during a glue up, don’t put the dowel in). Basically I’m using the width of the bar to create a square, then finding the center of the square to locate where the dowel would go. Then I drill the hole for the dowel, in this case a 1/4 in. hole. Alternatively just glue the dowel in the very last hole.
[Below] Now we create the detents. I’m using the spacing of the holes to place the detents. First I make a shallow kerf for each one. (Note: make sure you are doing this on the BOTTOM of the bar, not the top. Happily I’m not speaking from experience here.)
[Below] Now, using a nifty rat tail rasp I got off of eBay for about $0.05 I hog out the detents, bringing each one to the depth of about half the diameter of the rasp.
[Below] Now back at the workbench I’ve put the new stop on the bar and fastened the bolt through it. To keep the nuts from loosening I’m putting a dent in the groove between the threads of the nut and bolt with a punch. This is the best way I’ve found to do this.
[Below] Now I glue in the dowel and set it with a mallet.
[Below] And Bob’s your uncle! It’s done! (Note the kerf I made, but didn’t make into a detent because the new stop won’t work there. I put a detent half way between them which is usable.
-- Ni faru ion el ligno!