Tuesday, August 11, 2015

Moxon Vice

My shop is growing like I think many shops on a budget grow: slowly, and as needed. The things I don't have, could easy furnish a very nice shop on their own. One of those things I don't have is a nice bench. Oh I know, its supposed to be first on the list, but the thing is, I do have a workbench, sort of.

It started out as homemade staging planks when I was fixing my house just after moving in. The planks I made are 10-feet long, and just over 2-feet wide, with 2x4 framing and 3/4-inch plywood tops. I set these on post jack staging and they were much sturdier than 2x12s. A few years later, I added some legs, some stretchers, some plywood scraps on the ends and across the stretchers and that is my bench.

Not very glamorous.

But I've mounted my grinder at the end, and then my drill press. So now its crowded too. But the wedge vice I had on there for a few years had some obvious limitations. I don't have a hundred bucks for a bench vise, and I've seen some nice Moxon vices on YouTube, and elsewhere on the internet and thought that a variation of that would work for me.

Moxon vices are typically a benchtop affair, set atop the bench and held in place with some clamps of hold fasts, and set so that the rear chop or jaw of the vice is flush with the front of the bench. This assumes you don't need it often enough to mount it, and because its raised above the surface of the bench, the height is more convenient for fine work like dovetailing, so you don't have to bend over.

My idea was to use it as a bench vice, set flush with the top of the bench, and add dog holes so I can also use it to hold items on the surface of the bench. So my Moxon is more of a hybrid between a Moxon and a double-screw bench vice.

Designing my vice started by thinking about it. I liked the idea of the heavy wheels that I saw on the nicer Moxon vices, they were weighty and you could give them a good spin and they'd tighten right up. But I also liked the wooden screws because they're bigger, and the edges of the threads aren't sharp like a lot of threaded rod is, so it doesn't cut into your work. Then it occurred to me: I've seen something like this before, when I was younger and used to lift weights.
After looking at the options, I was happy to see that there is a built in shoulder at the end of the thread to act as a stop for the rear chop, and they have these heavy steel floriform nuts* that take the place of the cast iron hand wheels in the fancy kits. And, they're threaded on both ends so I could cut one in half and $20 would give me enough for two vices! So wow, right? But the threads are little short, and if I'm going to make chops out of 6/4 or 8/4 hardwood, I'm no going to get much of a range with these things from they way they look, and there aren't any good dimensions on how long those threads are on the various places I looked online. So it was off to the store to see if I could find the dumbbell handles with the longest threads, and what do I find? This crazy thing:

Golds Gym 5-foot Weight Lifting Bar


Its a weightlifting bar that comes in three pieces. The two ends are solid, 1-inch diameter solid steel, threaded, with an integral stop like the dumbbell handles, The center piece is a hollow pipe, that slips over the end bars, and is fixed in place with set screws or something. Seems like a crummy idea for a weightlifting bar, but great for a vice! The threads are like 10-inches! This bar was about $25 at Walmart (corrected).

There are 3 of these with holes lined up. 2 under, and 1 in front of the bench.

So, I came up with a simple design to hold the threaded rods in place, so I can install this under my bench, and feed it through corresponding holes in the 2x4 holding up the front edge of the bench. Its a few pieces of 3/4-inch plywood, with holes large enough to allow the rods to slide in and out, but small enough to catch the raised stop at the end of the threads, and two side pieces of plywood  to hold them together makes a rectangular frame. [Let me know if you'd like to see a SketchUp model]

The completed Moxon vice with board clamped in place

I assembled the plywood frame, with the two threaded rods inserted. They don't fall out because the raised stops hold them in. There are corresponding holes in the front of the bench, so I slipped it in from below, and screwed the frame in place to the bench skirts. Then, with the two rods sicking out of the bench front, I slipped over the last piece of plywood, with holes aligned, and then the 8/4 white oak front chop and the nuts. Basically done.


BONUS: The rods slide back, out of the way, when not in use.

A couple of items to note: The rods slide in and out in the frame, so when the vice is not in use, I can spin the nuts out to ends, and then slide the rods away so I don't walk into them. The 8/4 chop is about 4-inches deep so I get an 1 1/2-inches or so of grip above the rods. Since I finished, I've added a couple of dog holes to the chop so I can use it to clamp work onto the surface of the bench too. Lastly, I made a 'wrench' out of pine that has a matching corrugated (floriform, right?) hole that fits over the spin nuts, and a short handle so I can torque the nuts tight.

I'm thinking about making some hand wheels out of heavy hardwood with the floriform shaped routed out, so they'll slip over the spin nuts. If I do, and they work, I may glue them on there (and I'll post it here.)


* floriform = flower shaped. The dumbbell folks call them threaded collars, spin collars, or star collars. They look more like flowers to me.