Introduction: Custom Bench Dog Clamps
I needed... nah, wanted more ways to clamps things on my workbench (see the instructable for the workbench here and read about it on my blog here). So in this small instructable I'll be showing you how to convert a set of cheap clamps to clamps that can be used with dog holes.
Materials you'll need:
- cheap clamps that are somewhat long
Tools you'll need:
- A welder
- A grinder
- A miter box/saw with a metal cutting sawblade
Let's get started.
Step 1: Removing the Bulky Head
In order to customize these clamps so they would fit through the bench dog holes I had to take off the bulky cast iron heads and make new heads. For this purpose I choose long clamps. Usually these clamps come at a set price, like a set of 4 regular clamps, or 3 slightly longer ones, or 2 very long ones. I took 2 sets of very long ones.
Initially I started off with a grinder to cut them away, but since the clamps were so cheap there was no pin through the head, and I found out I could also just take a hammer and hammer the heads off. This saved a lot of time and a grinding disk or two.
After the heads were removed, I'd cut part of the rod at a 45° angle so when I turned the cutoff around and attach it again by welding, I would have a nice clean 90° angle. It's important that the new head is at least as long as the old bulky head was, to ensure the clamps don't get skewed when tightening.
I measured out how long I would have to cut the rod in order to make the new head just as long as the old head was, and I took it to the miter saw. You can cut it with any saw that does 45° angle cuts through metal, but try to get it as straight as you can. I used a manual miter saw that I got while renovating a house. Not the easiest way, but it worked.
Step 2: First Welding
With the 45° angle cutoff pieces, you are going to make new clamp heads again. I didn't have a steel area handy to weld on, so in order to distribute the head I put a little sheet of metal on a kind of workmate, and welded on top of that. You want to make sure the angle you're welding the cutoff back on is nice and square at 90°.
Step 3: Adding "extras".
Technically after the previous step the clamps worked, but since the new head is very small, there's not a lot of clamping area and I didn't want the head to "dig" into the wood. So in order to redistribute the pressure somewhat, I wanted to add some extra flat pieces at the end.
I made a big mistake here. I wanted to have the new flat side at the same depth as the actual rod, so I took the grinder and started to grind away material at the rod. Instead I should probably just have welded on those extra supports right away. Because it's very easy to grind away too much material, so when you want to have the new plates level with the rest of the rods, you'll have to add in/weld in extra material again.... which I did. You can see on one of the photos that I had to fill up the gaps from grinding away too much. If I had just welded the new plates on straight away I wouldn't have had to put so much effort in them.
Having said that, even with the new plates flush with the rest of the rod, the heads were too thick again, and couldn't fit through the bench dog holes, which was the entire purpose of the clamps in the first place. So I took out the grinder again and started grinding down the head and tip of the head, so that I could get them through the bench dog holes.
Another thing when you have gaps is that it's hard to weld it close again because the material gets so hot it melts and drops away. If I'm left with a sizable gap I usually look for scrap pieces, such as old pallet nails to fill the gap before I start welding again.
Step 4: All Welded and Ground Down.
- hitting the head off from the original clamps
- cutting the clamp rod at a 45° angle
- welding that cutoff piece back in a 90° angle
- add extra support on the head
- grind everything down again good.
We've finished our custom clamps. I've made them quite a while ago actually, and they've proven to be extremely useful to the point where I use less clamps than I did before. Where before I would use 2 big clamps to clamps things on the edge of the workbench, now I often just use 1 of these smaller clamps.
I hope this instructable was useful. If you have any questions or comments I'd love to hear them.