Mortise?

Racking often occurs when you place a small piece of wood near one end of a vise without a similar piece on the other end. As you tighten down, the open end tries to close down more than the end holding the piece, so the vise sides are no longer parallel, and sometimes this can twist the work piece, or even damage the vise mechanism or the wood in the vise itself. It is undesirable at any rate, given the amount of force a vise can apply. Add the second piece to the other end of the vise and it won't rack.

The photo is of a little jig with several thicknesses of ply you insert to avoid racking. Without the jig inserted, tightening enough to work the piece on the left would possibly twist the workpiece a bit, making it harder to cut the dovetails 90 to the board's surface. which would produce a useless joint that cannot mate or glue up properly.

I'm beginning to acquire the materials to build the side vise. I've been thinking about this part of the project from the beginning and I'd really like to make a vise that's not complicated, economical, made of readily-available materials and will be rugged enough to do the job. I've already acquired the bench screw from Grizzly so that part is chiseled in stone. There is also the possibility of cutting an Acme-thread hardwood dowel for the screw if someone would want to try that. The rest of it, however, has been the subject of much thought, many revisions, redesigns, etc.

But now I've pretty much settled on Doug fir for the jaws with hardwood faces. The vise framing will be integrated into the bench frame and will also be Doug fir. There will be a steel plate on the front that will perform two functions: 1) Hold the adjustable jaw square with the rear jaw, and 2) capture the bench screw. The guide rods are plainly going to be an experiment and may have to be redesigned somewhere downstream.

I intend to make them out of 3/4" hardwood dowels that ride inside sections of 1" Schedule 40 PVC pipe. The PVC has an inside diameter of just over 3/4" so that seems OK. The outside diameter of the PVC is just a hair under 1-1/16" so I will have to acquire a 1-1/6 (27mm) Forstner bit (if I can find one) or a 27mm hole saw (which are available for about $6-8). There will have to be sufficient framing to prevent the guide rods from racking and/or binding...I hope.

It'll be interesting...wish me luck. I'll get started on it shortly and I'll post progress pics.

ADDED: I should make it clear that what I'm trying to accomplish is design and build a cheap, usable vise that someone of modest woodworking skill can copy with readily-available materials. For those of us with relatively modest means, dropping about $150 on the materials for the basic bench is tough enough without having to pony up a similar amount for a side vise. I already made a cheap Moxon-style end vise out of a couple pipe clamps and it works very well. If you missed that, here is a link.

Got started on the side vise today...began by boring the holes in the front and rear jaws and the rear support. Pictures below. The jaws and support are Doug fir, the outside of the guide rods are 1" Sched 40 PVC and the inside guide rods are hardwood dowel. We'll see how this works.

You may notice what look like square holes in the rear jaw. That was the initial design but I changed it to make it easier to build...and easier for anyone to replicate. The initial holes were square and 7/8". The current holes for the guide rods are 27mm (1 1/6") and the PVC fits very nicely. The hole for the bench screw is 1", the actual diameter of the bench screw.

The jaws were bored by carefully measuring the first one and then double-sided taping the other two...one at a time...to it and using the first holes as guides. It came out nearly perfect...I will need to do a TINY but of sanding on one of the holes.

The finished vise will have hardwood jaw faces. I haven't yet determined what species...I'm leaning toward maple or beech but I'll have to see what the comparative costs are.

I'm hoping this will serve as an example at the kind of work that is possible in a small, modestly-equipped shop with mostly older, low-cost machinery and tools.

Here are the pics:

Got a little farther on the side vise...notched the top and edging so the vise would be flush with the top and bored the holes in the skirt. Chamfered the front jaw and dry-fitted the parts. Still need to acquire a steel front plate to capture the bench screw and distribute the force evenly to all parts of the jaw. Here I'm thinking of a readily-available 3 1/2" fender washer with a 3/4" hole. I'll cut it in half, mortise it into the front jaw (it's 1/4" thick) and drill holes for screws. And I still need to cut the PVC and epoxy the guide rods into the front jaw. It's coming along...here's a couple pics to show progress. In the first pic the vise is not assembled correctly but I wanted to show the perspective of the bench with both vises visible.

Today's work is not visible so no pictures. Fitted and refined the under-bench support for the guide rods in preparation for epoxying the outer guides into the rear jaw and under-bench support, and epoxying the inner guides into the jaw. The work was tedious and took about three hours. There was a lot of fine tuning and tweaking. I did install the threaded flange for the bench screw in its final location but have not fastened it to the support yet. I took the opportunity to clamp a small board in the vise. Even without the steel front plate it holds TIGHT. I didn't want to tighten it too much and damage the jaw but that brief test was very encouraging. The next increment will have to wait until I have acquired the front plate (a 3 1/2" fender washer, 1/4" thick with a 3/4" hole). I'll cut it in half and drill and countersink screw holes. Then I'll mortise the front plate into the jaw, install the bench screw and do the epoxying. That should finish it off except for the hardwood jaw faces. Pics to follow where feasible.