Over the years I've made a few different types of bar clamps and while they all worked I thought I could improve on them. All the ones I've made were out of wood, they could apply a fair amount of pressure but I wouldn't say they were heavy duty. Also they all required a pin or some sort of nearest adjustment stop and then tighten up to that, which I found annoying - especially in the middle of a difficult glue up. My new clamps are heavy duty, fast and extremely easy to use.
Step 1: Preparing Parts
The decision to make 8 clamps made this a fairly time consuming project.
There was a lot of cutting and grinding, mainly the side walls of the head and foot of the clamps.
The adjustment of the clamp works with a threaded rod welded to the underside of the main bar (steel box section) where a nut cut in half attached to the foot engages the threads.
Step 2: Welding the Foot
I used a mig welder with flux core wire for this project. This obviously worked but was not a good option. It was messy and there was a lot of clean up. A Tig welder would have been my choice, I think that would have really helped the project out.
In the first step I drilled holes in the side walls of the Head and Foot pieces to aid in lining up the parts to weld. Then I used the holes to spot weld the part and finished off welding with a bead along any seams.
To centre the half nut on the base of the foot I made a jig out of a few scraps of wood and hot glue. I also used blocks of wood to clamp the parts around to line everything up. On this foot section the box section running through the middle is set on an angle and the only way to get the wood out was to make it in 2 parts.
Step 3: Clamp Screw
The screw, for tightening of the clamp was made with M16 (5/8') threaded rod. M12 (1/2") could've been used but I'm hoping the threads will last for years to come with the bigger threads. There was just enough room after grinding the nuts down to turn inside the head of the clamp.
Step 4: Welding Head
This was similar to welding the foot but the screw needed to be attached. I also added runners to sit under the main bar to keep the head from racking.
Step 5: Making Main Bar
This is pretty straight forward, I made a jig out of wood scraps and hot glue to keep the bar centered while being welded. This worked out great.
The threaded rod was left about an inch short at the foot end to leave room to put an end cap on.
Step 6: Attatching Head to Main Bar
I made four clamps where I welded the head directly to the bar and four more where the bar could be removed to use with longer bars. The removable heads were welded to 20mm box section that slid nicely into the main 25mm bar then bolted with a single bolt. I made the inner bar fairly long 250mm (10").
Step 7: Handles, Clamp Faces and End Caps
Next I put a bit of paint on the Head and Foot, I chose a bright colour but it wasn't until I put the paint on I realised it was Ryobis colour. Then my 9 year old boy comes home from school, first thing he says when he sees the clamps "Ryobi".Rather than making round handles I kept them square to help with grip when tightening. On past clamps I've drilled a hole large enough to accomodate the threaded rod but even though glued in I've had the handle slip on the rod. This time I drilled the holes smaller (15mm to accept 16mm rod) so I had a tight fit to screw the handles on. The holes were a little to tight and the handles wanted to split (only slightly) so I filed a groove into one of the clamp head screws and tapped all the handles. With epoxy they are going nowhere.
Clamp faces were made from wood and hot glued in place.
The end caps were made from a short piece of 30mm box section with a cap welded on, these are to stop the foot from falling off the bar. I screwed in from underneath with a self drilling screw.
Step 8: Finished Clamp
Thats about it. To use the clamp the foot needs to be lifted a little and will freely slide along the bar up to the workpiece then it can be clamped with the clamp screw.
I hope this is useful to someone! Any questions just ask.
The video shows it better in action.