Vise design question

[Dennis Aspö]

I just bought a trapeze thread (metric acme equivalent) and nut to make a leg vise with. It's basically all I got hardware vise. I'm just not sure what the best way would be to hold the vise face captive without purchasing hardware or turning to a machinist. I would like to skip such steps to be honest.

As I've planned it out on my head, I'll just drill a hole in the workbench leg for the nut and epoxy it into place. Could also recess it and the area around it and fit a square washer for looks and durability. If you epoxy on a big wooden nut with a hole for a dowel on the threaded rods end, then you have a setup that'll push on the vise face when you close it, but it'll remain in place when you unscrew it. How can you "capture" the vise face so it also opens? And are there better methods than what I just described (that don't involve purchasing a bunch of hardware).

Maybe a bit hard to explain what I'm after here, and its almost midnight here and I am tired so I am probably not at my best, so good night, any answers appreciated.

[Jim Matthews]

You will need a front guide bushing with some "play" to allow the
chop to align properly at the last, when applying clamping force.

Cut a recess into the rear of the leg that will house the Trapeze thread nut.
If you can make it hexagonal, and drive it into the leg as a housing
the tension of closing the chop will pull it in tighter, each time.

The following picture of the Benchcrafted Moxon vise shows a square
recess in the rear chop to house a nut, as I've described.

You need to put this into the leg that will work as the fixed half
of your leg vise - on the side opposite the clamping face.

302985

[Charlie Velasquez]

If you have a lathe, or use a drill as a reasonable facsimile, mount the screw. Then using a file remove the threads for maybe 3-4mm at the spot that is about a couple of mil past the nut, whatever head you construct for the handle and maybe a washer or two. You will then make a skirt to capture the de-threaded screw and secure that to the chop. The skirt is usually a rectangular washer cut in half.

edit- when you remove the threads you also need to reduce the diameter of the rod a smidgeon, else the skirt will catch on the threads. You want the skirt to rub against a smooth piece of metal.

[Dennis Aspö]

Thanks for the tips, I now have a pretty good idea how to make this vise. Good idea about cutting a square washer in two, that's exactly what I was puzzling over how to solve...

[Jim Koepke]

As always, pictures help.

I started a response then realized I am not sure if this is a wooden or metal screw. Because it is like an Acme thread I would guess it is metal.

The piece that holds the moving face (chop) of a vise to the screw is often called a garter. It rides in a slot machined into the screw. They can be mounted in a mortise in the face. The can be made to be decorative and mounted on the front of the vise.

It can also be incorporated into the piece that holds the handle for the vise.

jtk

[george wilson]

You could recess an enclosure on the back side of the face of the moving jaw. screw a nut,perhaps with a washer under it into the recess,and epoxy it into place on the THREADS,not into the wood. The nut needs to turn freely and it will pull the jaw out as you crank the screw. That is not the best way in the world,but it can be done without a lathe.

[Jeff Wittrock]

I did pretty much what George suggests about using a second recessed nut. Only instead of epoxying it to the screw, I drilled a hole through the nut and screw and inserted a roll pin.

I'm not sure how hard the acme screw is, but it might now be to hard, with some care, to just file a shallow slot all the way around and use a garter in the slot as other suggested. I've done this before on some other things (not an acme screw). No need for a lathe, just some manual labor :).

[Jim Ritter]

Any chance you can post a photo of the screw at the handle end? We might have some other ideas if we can see what you are working with. You got good advise so far, but there might be others.
jim

[george wilson]

I did not suggest drilling a hole and inserting a pin though I thought about it. It might be difficult to insert the pin(and get the hole to align!) when the nut is threaded into the carved out recess for it. Perhaps a hole drilled just BESIDE the nut through only the screw would be sufficient,and reachable. I'm not really crazy about epoxying the nut actually. If the hole was drilled right up next to the nut,it would still keep the nut from turning. Excessive backlash needs to be avoided else your vise will forever seem sloppy and unpleasant to use.

[Dennis Aspö]

I had not seen there where further replies to this thread, but I am wondering about bronze bushings, I'd like to install one on the leg and perhaps on the chop as the washers I use bind it rather than help it glide, they are thin enough that they get sorta trapped on the threads and it makes the vise not as pleasant as I think it could be. A thicker bronze bushing would be the ticket I think and I can get those for 5-9 euros a pop. At least on the leg I think it'd be good to have one, but I don't think that it would hurt to have on in the inside of the chop either.

My main question though is, I have a 24mm thread, should I go for a 24mm bushing, or should I go 1mm larger?


Jim Ritter it's just a threaded rod with a nut, there's no handle end, either side would be as much that end as the other.

Edit: Also I'm sorta contemplating adding a linear bearing and rod instead of the old fashioned parallel guide, as the same place has a 20mm interior diameter bearings for 14 euros, and I have lots of 19mm piping. Question though is if 1mm of slop is too much. I remain undecided.

[Curt Putnam]

Talk to Jim Ritter about his chain guide. He sells a slick product for not much money - should be cheaper & easier than trying to rig a linear bearing.

[Dennis Aspö]

I don't think it can beat 14 euros, but if it wasn't already obvious I'm not for buying ready made systems, if I was I wouldn't have bought as bare a setup as I did. But how else am I going to learn to do things myself without some challenge?

This is also going on a rough bench with an OSB top of all things, not a nice joiners bench, and is made mostly out of surplus spruce and pine construction lumber. Practice before building a roubo style bench, just one of many skills I want to acquire.

[Phil Stone]

I hope this won't be considered a thread hijack, but I'm designing a leg vise as well, and I've looked at Benchcrafted's designs quite extensively. Could somebody explain to me the use of the delrin guide bearing on the front of the bench leg? It looks like the most recent BC designs for this bearing have the hole that the screw passes through elongated in the vertical direction, so that it seems that this bearing only prevents the vise screw from moving side-to-side. Is this correct? Does the bearing have no support function for the screw?

More generally, is some sort of support bearing in this position advisable on a thick-legged bench?