Some Questions About Making Vises

[James White]

I need to make vises for my Roubo style bench. The bench top is 3-1/2" thick Ash. I have four of the Woodcraft bench screws that I will be using. They are 1-1/8" diameter by 19" long. The bench has a 5" wide leg centered on the face vise location and is flush with the face of the bench. I may add cogs and bike chain at a later time. Any ideas on how to do this?

How thick should the chop be for a twin screw vise on 24" centers? The chop will be Ash but I am not sure how tall yet. Would 8"be a good height? What size hole should I bore for the screws? Should they be snug so they support the weight of the vise?

I am not sure how to build the end vise. I do not think I want a twin screw there. So how do you build a vise with only one screw? I did not want a wagon vise since you lose some bench length. I have a small lathe and mill. But I am hoping that they will not be needed for this. Are there any plans for a basic single screw vise?

James

[David Keller NC]

James - I'm not why you'd want to retro-fit a set of gears and a chain to standard bench screws, unless the machine work necessary is just something you want to do. You'd have to cut off a section of the screw thread close to the t-handle end to mount the gears (and also machine a flat or a slot in the screw shaft to mount set screws or a slotted keyway to hold the gears still), then remove links to the chain to get the chain tight enough to function well.

One aspect of this is that you'd have to be certain of the vise screw's spacing before you mount the vise, whether or not you installed the ganged-screw function at the time of installation, because if your chosen spacing meant that one number of links in the chain was too loose, but one less was too tight, you'd have to change the vise screw spacing.

All in all, I'd think it'd be a whole lot easier (and cheaper) just to purchase Veritas' twin-screw set-up.

In regards to a tail vise, I don't know of any quick resources on the net that include plans, but there are a number of photos and drawings in Taunton's "The Workbench Book" that should give you some ideas to draft some plans of your own. One thought about tail vises vs. wagon vises - you still lose the area of the benchtop that the tail vise occupies, because chopping, clamping and other operations on top fo the tail vise chop is a no-no - it will cause the vise to sag significantly over time. That's one reason that Chris Schwarz has written that he likes wagon vises better - while you do lose some benchtop area, it's typically not as much as a tail vise, and installation is considerably simpler.

Tail vises are complicated beasts - I've made and installed 3 of them, both all-wood versions and a version built up from metal hardware and wood stuffing. Either way, the construction and fitment to the bench is fussy.

Personally, if I do it again, I'm just going to make my life much easier and install a Jorgensen quick-acting vise in the end position. Mounting is a matter of mortising the bench apron or end for the rear jaw, and 2 bolts and 2 screws - worlds simpler than building up a tail vise from a metal frame.

[James White]

Hi David,

I think I should have been a little more clear about my end vise. I am not looking to make a tail vise. I just want to make a simple end vise utilizing the screws that I already have. I am thinking that perhaps a 12" chop with the screw centered and one piece of 3/4" in black iron pipe on each end will work. Only am not sure how to secure the black pipe to the chop. Perhaps an press fit with some epoxy?

As far as my comment regarding the wagon vise. I was not concerned about losing bench top space. But rather holding capacity. My bench is 95-1/2" long. With a wagon vise I would not be able to hold an 8' board.

As far as the twin screw vise goes. At this point I just need to know if a 2-3/4" chop will be adequate for a 30" long vise. I have enough 8/4 to go thicker but I would just be wasting material if one piece of 8/4 + one piece of 5/4 will suffice. That would come out to about 2-3/4".

James

[David Keller NC]

"Only am not sure how to secure the black pipe to the chop. Perhaps an press fit with some epoxy?"

I think you may have difficulty getting the arrangement you described to work smoothly. Since the end of your bench/apron is wooden, the holes for the black pipe acting as guide bars will need to be at least 1/16" larger than the diameter of the pipe to avoid locking the bars irretrievably in the bench when the humidity goes down. Still, if you want to try it, I'd suggest drilling blind, flat-bottomed holes in the inside of the vise chop, then drilling a hole at 90 degrees to the seat through the top or bottom of the chop and black pipe, then pinning it with a piece of mild steel rod. That'll absolutely prevent a potential for the glue to fail and the black pipe not moving with the vise chop. Another advantage to this set-up is that it's easily taken apart if need be.

Regarding the chop thickness for your face vise, I think this depends on the material you plan to use. If it's maple, 2" should be enough to not flex too much when clamping smaller things (wider items like case sides will be closer to the screws, so flex isn't as much of an issue). However, if you plan on using a weaker/more flexible wood, I'd make the chop 3" thick.

I'm basing this on experience with a twin-screw Veritas vise that I installed on a bench I made 5 or 6 years ago with a screw width of about 20". The chop I used was 2" thick maple (finished dimension) that overhung the vise screws by about 4" on each side, for a total width of 28". I did see some flex in use, but I had to crank down really hard on the vise for that to be a problem, and it only showed up when gripping smallish pieces of about 4" wide - wider items didn't really flex the vise chop all that much.