Hardwood clamp, Dubuque Variable-angle Wooden Clamp

I noticed these clamps mentioned by Bob Rozaieski on his Fine Woodworking internet site when we were in Spain this year. I researched the design and started to try and find sources for the hardware, mainly rods that had right hand and left hand threads on the end of each rod. As you can see below, the jaws can be angled for clamping and are also useful for holding work pieces above the normal bench vice, e.g. when making dovetails. The clamp can be operated by holding one handle and turning the whole clamp to speed opening and closure.

Variable-angle wooden clamp. This is the one that I made and gives an idea of the components and operation.

I eventually found a source for the threaded rods at "fine-tools.com" (shipped from Germany) as they sell the clamps and also supply kits that can include the rods, four swivel nuts, ferrules, two rolled spring pins and instructions. These kits are made by "Micro-Moose" of Dubuque, Iowa in USA. They also have the handles available but I decided to make my own, in fact this was the first thing I did. Both were from odd left-overs from green woodworking projects, one of Ash and the other Silver Birch and even though they were dry, it was easy to use the pole lathe to turn suitable handles that fitted well into my hand. One end was turned so that the ferrule fitted snugly but as far as I can see the size and design is up to you.

I made the clamps with some solid Beech (obviously a hardwood is necessary) about two and half inches square. I made the largest one available for the ironware kits from "fine-tools", i.e. 14 inches arm length and 10 1/4 inch jaw opening. Other options are 4, 5, 6, 8, 10, 12 as well as 14 inches. I am not going to go through the details of the dimensions etc but feel free to contact me if you need that kind of information. I will just go through some of the construction not covered in detail in the instructions.

The stock was easily prepared to the dimensions using a Fore plane and Jointer plane to get flat surfaces. The holes for the barrel (or swivel) nuts were made with a 5/8 inch brace and bit, drilling from each end to meet in the centre to get a good alignment. The angled mortices were made by the traditional way with a chisel and mallet but using an angle square to judge the correct  orientation, e.g 

After drilling the holes for the barrel nuts, the angled mortices were chiselled using the angle-square set at 14 degrees. These mortices allow the threaded rods to swivel and so aid clamping non-parallel surfaces.

I found it important to get the correct steep angle so that the rods did not jam in the mortice. I checked the barrel nut and rod at each stage and made adjustments when  needed. It is also important to accurately match the position of the last barrel so that they are in-line and correct for the noses of the jaws to meet.

Marking the positions of the holes for the barrel nuts. The pencil lines indicate the angles of the long and short mortices.

The assemble of the clamp was straight forward noting that the threaded bars are of different length with the longer bar at the front and also that the wooden handles fit on the side with the longer threaded section. I found the best way of checking the set-up was to wind the jaws fully open to get the opening to about 10 1/4 inches (mine managed 10 1/2 inches) and then mark the position of the handle so that the threads couldn't be unwound completely. This gave a thread depth into the handle of 1 1/8 to 1 1/4 inches. I also checked that the clamp could be fully closed, i.e. the thread reversal on the bar was at the centre between the jaws.

The last stage was to attach the handles by drilling a central hole with a 7/16 inch drill and as a tight fit, screwing the rod into the handle with the ferrule attached. I did this with the jaws fully open to ensure the handles were fitted to the correct depth. A pin was fitted by a 4 mm hole passing through the ferrule and threaded rod. Finally the wood was treated a couple of times with boiled linseed oil.

To operate the clamp quickly you can hold one handle and rotate  the other handle to get an opening close to what you want and then make a final turns on the appropriate sides to tighten the grip.

I have another one to make in the future so may add some additional tips later.....and here it is. Straight forward and nothing really to add to the description. I did use a hand drill to make holes to start the larger mortices and found this helped the process.

My second clamp with ash handles turned from green wood. The arms are made from beech and treated with linseed oil. It is nice to be able to turn handles to a shape that fits your own hands!!