|Project by danriffle||posted 09-11-2008 03:46 PM||20713 views||47 times favorited||19 comments|
I’ve made a bunch of these little handscrew clamps. Of course, you can never have too many clamps. I plan on making some larger clamps in the future but these have been working for me so far.
The construction is pretty simple. There’s nothing really tricky about making the clamp—just keeping the pieces consistent and holes lined up. Threading the dowels is done easily with an inexpensive wood tap/die set. Birch dowel rods thread really well—so does maple, oak does not. I used scrap pine for the jaws and handles on these. The soft pine jaws won’t mar the things that you clamp.
The handles were drilled, tapped and then the threaded rod glued in. That worked okay but cutting threads into the end-grain of a piece of pine was a waste of time. In the future I’d just leave the end of the rod unthreaded, drill a matching hole in the handle and glue it. The handles were shaped by making taper cuts of each face on the bandsaw freehand. Then they were shaped with a drawknife. I have turned complete handle and rod pieces, but for me it was a lot more work for something that I dropped and broke a few months later. (Half inch threaded dowel is somewhat fragile and will break if dropped, but it has a remarkable amount of clamping power. I’ve only dropped one…)
Makes a nice Christmas present for the other woodworkers in your life, but my wife wasn’t impressed ;)
UPDATE: here are some details for those wanting to make their own clamps.
1. You’re going to need to be able to thread the clamps. These were made with a 1/2” threader. The kits are available from a lot of distributors and they all look like the same thing to me. I like Highland Woodworking’s kit because it comes with 2 taps; standard & bottoming. (Sorry, no pic) When you get your kit, read the instructions (they are simple). Then play with it on some scrap—drill some holes & tap them. Get some dowel rods & thread them.
2. Cut the jaws. These clamps use a 1 1/2” x 1 1/2” x 8” pine jaw (perfect for using up 2×4 scraps). Obviously cut them in pairs. The taper that I put on the jaws starts 4” back from the front and tapers to 3/4”. I cut it on the bandsaw, but any saw will work—this is certainly not a critical cut. The inner jaw (non-tapered side) needs to be nice & flat so they fit together as nicely as a glue joint. You may want to ease the edges so it’s not sharp and could potentially ding a piece that you’re clamping.
3. Drill the jaws. This is the only tricky thing and even this is fairly forgiving (my first pair we’re exactly precise, but they still work okay, the jaw just don’t line up pretty when it’s closed).
Naturally, you want the holes perfectly vertical, so a drill press is almost essential, but a good drill guide might work if you don’t have a press (or if you’re a chairmaker, you may be that good with a brace & bit). If you’ve got a good eye, you’ll notice in the picture that the holes in the jaws are not identical. For the jaw on the left, the upper hole is a full 1/2” (even slightly oversized) the lower hole is 3/8” and only bored 1/2”-3/4” deep and neither hole is tapped (that is, threaded). For the jaw on the left, both are bored at 3/8” all the way through and then tapped. The holes should be placed on center about 1” & 3 3/4” up from the butt (non-tapered) end of the jaws.
4. Make the handles and rods. Starting with the handles, again I used 1 1/2” x 1 1/2” scrap pine about 4” long. Bore a 1/2” hole centered on one end about 1 1/2” to 2” deep. After drilling, I tapered the handles on the bandsaw and whittled them to a shape I liked with a drawknife. You could also turn them on the lathe or even whittle them with a pin knife. Next cut your rods to length. You want about 6” of thread plus unthreaded blank to go into the handle—so, 7 1/2” to 8” rods. NOTE ON THREADING: dowel rods can vary tremendously in diameter. To save some frustration, bore a 1/2” hole through a piece of scrap. If you’re dowel rod won’t slide easily though that hole, you need to sand it until it does (or take the scrap with you when you go to buy your dowels and only pick ones that are the right size). Of course you can always turn your own rod on the lathe…
Make sure to leave that bit of unthreaded stock at the end of the rods—glue that into the handles and let it cure. If you’re nervous about it coming loose, drill a tiny hole in the handle and tap a brad through the handle and rod—personally, I wouldn’t sweat it.
One rod needs to have a different end—the pusher rod. It needs to have a tip that will fit loosely into the 3/8” stopped hole in the jaw. So, whittle the end of one of your rods to size.
5. You’re ready for assembly. Take the jaw with the threaded holes and insert the pusher rod into the lower hole and run it almost all the way up to the handle.
Then insert the other rod through the upper (loose) hole of the other jaw.
Then line up the pusher with stopped hole in the opposite jaw and start threading the upper rod into the threaded jaw. After a dozen or so turns the assembly should be snug enough that you can “bicycle” the handles to close and open the jaws. VIOLA—a clamp!
Additional Note on Threading: a little parafin wax on the threads can be a good thing but I don’t apply any finish to the clamps at all. Don’t even wax the threads until you assemble the clamp and make sure it’ll turn smoothly. If it’s hard to turn and screams like a banshee, you may need to: 1.) sand the threaded rods a bit more, 2.) re-tap the threaded holes in the jaw, 3.) adjust the cutter forward in the threading box and run it back over your rods.