The new Bessey STC-HH70 auto-adjusting clamp.
I was recently in touch with Bessey Tools North America. They were offering some clamps for me to try out and asked if I would write a review of exactly what my thoughts were- good, bad, or ugly.
The clamps are a new style of toggle clamp that allows for a range of auto-adjust clamping. I was curious how they would work, because others that I’ve tried required me to change the height of the clamp whenever my material dimensions changed. And being that I work with a wide range of thicknesses, I have never had luck with other toggle clamps.
My first impression of the clamps is that they were bigger than I expected. The particular one I tested recently, the STC-HH70 (pictured), is listed as having up to 550 lbs of nominal clamping force and 700 lbs of holding capacity, so I guess they would need to have some heft to them with a length of about 8 ¼”. There were 2 styles of clamps I was going to try: one that has the clamp come down onto the work piece from above, and one that pushes forward against the work piece. I had intended on starting with the one that pushes forward, but it was just too long to fit into my crosscut sled. I was, however, happy to find the other clamp was a perfect fit.
Bessey auto adjust clamp holding down a pen blank on the table saw crosscut sled.
There are a few adjustments you can make to the clamp. The most obvious is probably the height adjustment, the threaded part with the shoe that comes into contact with the work. But that also slides forward and backward, which is really quite convenient when working on multiple pieces of different widths. The last adjustment is near the base of the handle. It is a small screw that lets you adjust the clamping pressure. Some pieces require a more delicate touch, giving just enough pressure to hold it in place, and this really helps find that balance of good strength, but not crushing strength. This is especially important for me when working with softer wood.
My first try was on a piece of Red Mallee Burl, which was going to be used for a high end fountain pen. Because of the size of the finished pen, the holes that need to be drilled are rather large (37/64”), and any wandering of the drill bit can make one side too thin to be turned into the finished pen. I used the clamp to cut a perfect 90 degree angle, which will later stop my drill bit from trying to wander. The wood clamped in easily and was held rock-solid.
The Bessey clamp holding the now-cut pen blank in place.
My second attempt was a piece I really wasn’t going to try at first. It just seemed kind of risky and I figured I might be better off cutting it on the bandsaw like I usually do. It is a 1 ½” acrylic cylinder, and after giving it some more consideration, I figured it would be a great test.
Bessey clamp holding down a cylindrical piece of acrylic.
Close-up of the Bessey clamp securing the work.
As you can see in the picture, the part of the clamp that comes into contact with the cylinder is able to pivot. That, coupled with the automatically adjusting clamping height, allowed me to literally swap out the Red Mallee for this without any adjustments to the clamp. The Red Mallee was 1” thick and square, this is 1 ½” thick and round. Before I fired up the table saw I gave the acrylic some really good tugs and pushes to see if I could get it to pop loose. When I saw it wasn’t budging, I went ahead and made the cut.
- The acrylic stayed in place perfectly throughout the cut!
Part of me was surprised with the cut. There was no wobble, there was nothing that made me think, “Oh man, this was a bad idea.” Another part of me wasn’t surprised at all. Bessey has been making clamps since 1936, so it’s not far fetched to think they know what they’re doing. Ultimately I couldn’t be happier with the clamp I was able to test. I hope to get some other jigs made in my shop in the near future to utilize the other style, as well.
Oh, and that Red Mallee Burl pen I was working on? I’d say it turned out pretty nice, I hope you think so, too
Red Mallee Burl Fountain Pen by Greco Woodcrafting.