Introduction: Pivoting Arm Vise Mount Build

About: I was pfred1 but moved, changed my email address, and lost my password. I suppose worse things could happen.

In this article I will describe how I made this pivoting arm vise mount for my workshop. First I might as well try to explain why I might do such a thing. Because many might ask why would you want a pivoting arm vise mount? I think it is a completely valid question too.

For the longest time now I've wanted a metal vise over on my electronics workbench. Because every now, and again, my little Panavise with plastic jaws just doesn't cut it for some of the things I might do working on some of my electronics projects. Then I have to get up, and go over to my metalworking corner, and use one of the vises over there. I know, the horror of it!

Now to further compound the issue my electronics workbench is also my desk, so I am not too keen on just drilling holes in it, and mounting a vise regular style on it. Not that I really have a suitable place to do that anyways. All of these various factors converged into a need for a pivoting arm vise mount for me. Well plus the fact that this spring I picked up a little bench vise at a yard sale. So the time was ripe for this project over here.

Step 1: A Plan Was Hatched

I went out on the net and looked at all sorts of different specialty vises. OK maybe four, or so. Then I got to sketching a bit. I did more sketches on paper, but this was a picture I tried to draw on my computer. I think we can see the design elements taking shape here.

There is going to be a clamp on the desk, with a pin coming up, off of it, with a cylinder around the pin, that is boxed, then a swing arm coming off of that, with the mounting plate on the end of it. Sounds reasonable.

Step 2: Step 1 Make the Clamp

In this step I have added two pictures. One is an early picture of the clamp just done, with no pin on it yet. We can notice the cramped space I am working with here too. The second picture is the completed clamp assembly after being painted.

Now I will describe how I made the clamp. First I took a suitable piece of angle cut off, my piece happens to be around two and a half inches long (2.545 to be precise) with what looks to be about 3.5 inch long legs (3.600). I welded a thicker piece of scrap to that piece of angle to make a C shape, and I also added some bracing for the belly of the clamp too.

In the next step I will discuss the moving parts of this clamp.

Step 3: Clamp Movable Parts

I took the clamp pad off to get a detail shot of everything going on here. The pad is held on by a little 6-32 button head Allen screw. There is a counterbored recess in the pad for the screw head. I should add that there is another counterbore on the other side of the pad for the adjusting screw to sit in too.

I found a washer that is a good fit on the 6-32 Allen screw. I put that in there so the pad does not unscrew the screw while in use. The pad itself needs some thickness to it, to accommodate the various machining operations it has to. So the pad is made out of half inch thick stock. It was square, then I clipped off all of the corners, to give it an octagonal final shape. For the screw handle I put another nut onto the adjusting screw, and drilled through it, and the screw. Then I found an appropriate nail, and put that into the hole. I peened one end of the nail so the tommy bar handle would not fall out of the screw.

The adjusting screw itself is a piece of 1/2 x 13 UNC threaded rod. All of this works well together.

Step 4: The Pin and Cylinder

These are odd pieces of stock, so I had a good look through my junk collection to find them. The pin is the nose of an old, and dead, air chisel, that I had lying around. The cylinder I had cut off the frame of a basketball net support years ago. It was some kind of pivot for the apparatus. You never know when these things will come in handy.

Anyhow, they were both excellent pieces of steel, and they fit together well too. The pin measures about 1.538 of an inch in diameter. The outside of the cylinder is 2.260 inches. This is the only picture I have of the pin, and cylinder together. I took it while I was priming them.

I trimmed some of the excess off of the air chisel nose before I welded it to the clamp. The pin has some thread on it that screwed into the air chisel body, I left a bit of that on, as a shoulder, for the cylinder to bear upon. Anyone using plain round stock is going to have to take this into consideration I suppose.

The overall length of my pin is close to 2 and 3/8s of an inch (2.310). It is not critical, it is what it is.

Step 5: The Cylinder Box

In order for this whole contraption to work I need to make a translation from the round of the cylinder, to a square shape, that I can attach the arms to. Now in a perfect world the simplest solution would have been to drill a huge hole into a large chunk of steel. But I can't drill a hole that big, and I do not have a piece of steel stock quite that large either.

So I opted to weld a piece of angle, and a flat plate to the side of my steel cylinder. A word of caution; the two opposing box sides that the arms are going to attach to have to be in parallel planes to each other. So to manage this I welded them as closely as I could, then I milled one face flat to the other. The plate I put on was a bit thicker, and I took some meat off of it machining them closer. I got the two faces to 0.006 of an inch flat to each other, which turned out to be close enough.

I figured if it wasn't I'd true it up a bit more. But everything works fine, so that is the tolerance here. I think the plates are pitching apart towards the mount. Initially I was going to assemble things opposite of how I did, but I like this way better. Plus I figured better the arms spread, than pinch. File all of this under this is how it worked out for me.

Then I had to locate where one of my pivot bolts would go in the boxed cylinder, and drill a hole for it. I have a whole box of these 5/8 x 11 bolts, so I decided to use a couple of those in this project. I picked the loose clearance fit for those, because that is the twist drill I have, and used it. That is 21/32nds of an inch.

Step 6: The Vise Mount

We're in the home stretch now! This is the last complicated major assembly to make. We'll still need the arms, but they're pretty plain compared to some of these other pieces. This piece is actually the most complicated of them all, but it was surprisingly easy to make. Well, it went together fairly straightforward at least. It did take me a while to make though.

Here is my assembly after I welded it up, and am in the process of cutting it to match the vise base. I welded it up out of 2 pieces of angle with a flat plate in the middle. When I had everything sized correctly I clamped everything to another heavy plate of steel, to keep everything aligned while I welded it. Of course the tabs on this piece have to correspond to the box section already made on the cylinder box. This is done by sizing the center plate correctly. Trim, and measure, trim, and measure, until it fits. I trimmed the plate by milling it on my mill. I took multiple light passes, sneaking up on the final measurement.

More about this part in the next step.

Step 7: The Vise Mount Continued

Here we can see the mount saddle upside down. I put a bar across the tabs, so the pivot bolt would not be able to crush the tabs in. There is also one place here that I would do a bit differently if I had it to do all over again. I would have put my bolt hole a bit further up, and away from the the mounting plate than I did. What I did works, but that hole out some more would work even better.

It was just something that I noticed when I put everything together later on.

Step 8: Cutting Out the Vise Mount

This was a step that I was really apprehensive about. I wanted the vise mounting plate to follow the contours of the casting on the bottom base of the vise I was putting on it. But this ain't soft pine wood we're working with here. I do not have a plasma cutter either. So I went with chain drilling, then cutting it out with my band saw. I still had some pretty tight curves to deal with though.

I came up with a technique that I am going to share here, where I cut the web between each drill hole twice, to completely remove it. This gave me a wider slot to work in. I stopped working, just to take a picture of what I mean. I would cut one side of the web away, then back out, and cut the remaining web side through, dropping the whole web away. That wider slot I made really gave me room to move making the cuts.

I still had to attack these cuts going in from both sides, and meeting in the middles.

Step 9: Contouring the Vise Mount

Chain drilling, and cutting the excess away with a band saw will only get me so far. To get a more refined edge I am going to have to use an angle grinder, and some files too.

Once the mount is contoured to the vise base I clamp the vise base to the mount, then using a transfer punch I mark where the mounting holes need to go. Those are drilled, then tapped. I used 5/16 x 18 UNC bolts for that.

Step 10: Designing the Arms

We're really in the home stretch now. All of the complicated pieces are made, and now just the connecting arms need to be done. At this point I felt the need to play test things out a little. I setup my clamp and pin, with the boxed cylinder piece on it. Then I bolted my vise to the mounting base I had made for it, and placed the vise on the workbench, in some proximity that looked about right, to the clamp and cylinder box section.

I then loaded the pivot holes with bolts, and measured between them with some inside calipers. Taking that figure I'd established, and doing some napkin calculations I arrived at arms 11 inches long. Which was considerably longer than I'd earlier guessed the arms would need to be.

But I had an idea at the time that when not in use I would want to pivot the vise overhead, and out of the way. When I was done with everything I found that idea impractical, and I just swing it out of the way in practice. But at the time I had other ideas. Those ideas were what I was working with too.

I also only had a piece of angle 20 inches long that I'd planned on cutting my arms out of too. Time to break out my angle iron stretcher I think? Because I can't quite get two 11 inch long arms out of a piece of angle only 20 inches long. One arm would be two inches too short. This step was supposed to be easy, what is going on here?

Finally after a lot of hemming, and hawing, and even dragging another piece of angle up off my stock pile, I abandoned everything, and went back to my original 20" long piece, and just decided to cut it in half, and those would be my arms. Because the other piece of stock I'd dragged up had legs too long, and I'd have had to trim that down, blah, blah.

It turns out that my initial swing the vise over the top plan was stupid anyways. If anything the 10 inch long arms are even a bit on the long side, but OK I suppose. So sometimes it pays to abandon ideas. Here I'm just going to put a vise swung out of the way picture. I will get into fabricating the arms on the next step.

Step 11: Making the Arms

OK so now I have a piece of angle about 20 inches long and I am just going to cut it in half. Easy enough. But not so fast, because these arms need to be exactly the same size. So I am going to cut the angle about in half, then clamp them together, and trim them square, and precisely the same size.

My band saw does not cut things perfectly square. I could probably fiddle with it, and get it closer, but the fact is it tracks off a bit. I accept this, and just cut everything, and expect to lose a little trimming things up. So after I cut my angle in half I spent some time making the pieces even with each other. I found the best match I could standing the angles up on a flat surface (I used my anvil as a surface plate), Then I clamped them up with a C clamp, and put them into my tripod vise, and had at them with an angle grinder.

Checking every now and again with a combination square I eventually got the arms about even with each other. All of this will pay off later drilling the bolt holes in them.

How I determined where to put my bolt holes. I picked out some appropriate washers, then laid them down on the inside of the angle iron, past the web, where they laid flat. Then I scribed where the inside hole of the washer was, on the angle. From there I scribed some cross hairs, and eyeballed where the hole belonged. I then centerpunched that spot.

I only marked one angle, and bolted the pair together, outside, to outside. When I drilled them I set a stop, so when I flipped the angles over I would have another hole in the exact same spot.

In the pictures for this step I am showing the spud I used to get my initial alignment. Then a center bit, that I used to start each hole, and finally the finished bore.

On my initial trial assembly I noticed I was not getting the pivot on the mounting plate piece like I expected. The corners of the arm angles were hanging up in the inside webs of the mounting plate assembly. Remember how I said I found out my hole was a little low? Well this is when I found that out. I just knocked those corners off with an angle grinder, and it is fine now. I actually scribed around the washer, then disassembled everything, and ground to the mark. Perfecto!

Step 12: Finishing Up

I do mean finishing up too. By finishing up I mean prime, then paint everything. Give everything a good cleaning, then wipe it off with a solvent. I used acetone. Once dry, assemble, and enjoy!

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