Twin screw face vise question

[Peter Tremblay]

Hello all,

I was wondering and wanted to ask the folks out there what their thoughts were about a twin screw face vise. I'm going to build a bench this summer and I want to put in a twin screw in the face vise position.

But I'm wondering about going with independent screws. Chris S has done this with the Holtzappel workbench and I think a couple folks here have done this as well.

So my question is: what are you thoughts on the independent screws? Are they fussy or difficult to use?
I like the cost (each metal one is about $40) and their simplicity but I'm also considering modifying the Veritas twin screw to add more chain so that I can get a full 24" between the screws. It would seem to me that in use the veritas twin screw would be easier to use.

Any thoughts or comments?

Does anyone have any experience with both or either?

Any ideas or suggestions are really appreciated.

Thanks
Peter

[Dewey Torres]

I have the Veritas twin screw vise and I will tell you a few things:

1) It is hard to improve upon the design of this vise (or make it easier to use). It comes with extra links for the chain by the way. Moving the screws outward will result in the beautiful cover (which also protects the chain and you) will not fit. BAD NEWS IMHO (Standard assembly will result in 15 1/2" between the screws)

2) This vise has a dis-engage capability that will allow the screws to turn independently and purposely rack the jaws. This is used to hold odd shaped pieces.

3) While I am not knocking the cost effectiveness of your single screw idea, there is no way it will result in an easier to use vise than the Veritas. I have been down the "cheaper" road so many times only to find that I should have went with the higher priced product in the first place. This could and will be a personal preference thing that only you will be able to decide. Good luck with your bench!

Dewey

[Wiley Horne]

Peter,

I have the Veritas Twin Screw as a front vise, and also as an end vise. You asked about the front vise installation, and other twin-screw options. In my opinion, the real option to the Veritas is not two metal screws, but two wood screws, approx. 2" diameter (if you search Chris S. blog, you can see them). The reason is that the wood screw set up will give you more clamping power at the top of the vise, owing to the fact that you have that large-diameter wooden cylinder that the vise handle goes through (what do you call that thing, folks, I'm having a senior moment about it?) driving the front jaw up against the work. Clamping power all the way to the top of the vise is very important--think planing a table leg.

So I suggest compare the Veritas chained twin screw with the wooden unchained twin. The decision may depend on the kinds of operations you will be doing more. The Veritas gives you very fast one handed operation, which means that you can hold and position the work with one hand, and open/close the vise with the other--all in one motion. For operations where you want the jaws more or less parallel, like most joinery sawing and planing regular boards or panels, you'll find the Veritas fast and powerful. There is some ability to adapt the Veritas to not-quite-parallel clamping--I get about 3/16" max. variation in clamping thickness from one end to the other. On the wooden twin screw, you'd generally have two screws to adjust independently, and it would be more fiddly in that regard. One thing I'm not sure about is whether the wooden twin has a faster screw--if it does, that would go some ways to offset the apparent speed advantage of the Veritas in normal (parallel) clamping situations.

On the other hand, the unchained wooden twin screw is going to excel at clamping eccentric or odd-shaped pieces. Like a small table leg which is, say, 1-5/8" square at one end, and say, 3/4" square at the other end. If I want to operate on that leg with my Veritas--and I did!--I needed to save my tapered offcuts to shim the vise with. Not a big deal, but the wooden twin screw would give you a lot of flexibility to clamp odd shaped pieces with little or no shimming. I suspect that the wooden twin-screw would also have less projection into the work area where your hip will sometimes be.

I'm very happy with the Veritas Twin, both as front vise and end vise. But I think for a front vise, it takes some thinking to decide between the Veritas and a wooden twin screw as shown on Chris S.'s blog (and probably in his book, which I would buy if I were going to build a bench).

Wiley

[Peter Tremblay]

Thank you Wiley,

I do have Chris S' book.

It never occurred to me that the wooden screws would be more powerful than the independent metal ones, thanks for pointing that out. I also did not realize that the Veritas could only skew that small of an amount. I appreciate your help.

Thanks
Peter

[Frank Drew]

Wiley

I think I understand your point about a 2" wood screw applying more force to the top of the vise simply because the cylinder of the screw is bigger, but steel screws are much stronger than wood and can crank down with much more force; the wood screw/nut combination, at some point, starts to flex, whereas an all metal vise set doesn't.

I'd think two independently operating screws would be a total PIA for anyone with only two arms and hands, for the reasons you gave.

[Wiley Horne]

Hi Frank,

No argument with anything you say! To clarify the point on clamping pressure at the top, I was comparing thrust plates more than the screw diameters. The 2" wood screw has a big round turnbuckle thingy driving it, that the vise handle goes through. That is effectively a 4" diameter thrust plate, which is integral to the screw. It shoulders against the front vise jaw. The thrust plate on a Veritas is stout too, and I have no complaint about it. I guess what I'm saying is that, if one is thinking about using two independent metal vise screws, take a close look at the thrust plate and think about whether it is has enough diameter and lack of play to really force the front jaw vertical for clamping horizontal sticks up at the top. The wood screws and their integral thrust blocks will do this. So will the Veritas. As a point of historical interest, the old tool catalogs have some really big fat bench screws. Greenfield's 1872 catalog offered hickory screws up to 2-3/4" diameter. Wonder whatever became of the machines or fixtures that turned those big screws.

All that said, I really like my Veritas with the chain linkage. This is because I mainly want parallel clamping, and appreciate the one hand operation, so I can stick the work in there with one hand and clamp it right now with the other hand. You can even skew it a bit one-handed when you get used to using it. But someone who who is going to clamp a lot of odd shaped things--tapered legs, cabiole legs, etc--might prefer independent screws cause they don't have a third hand to place the shims in position, and would rather adjust the two screws one at a time.

Wiley

[Wilbur Pan]

...that large-diameter wooden cylinder that the vise handle goes through (what do you call that thing, folks, I'm having a senior moment about it?) driving the front jaw up against the work.

Isn't that called "a big round turnbuckle thingy"?

[David Beverly]

Peter and Guys,
I recently finished a Holtzaffel bench with metal twin screw front vise and while I don't have a problem dealing with the two handles , Wileys comments are spot on in regards to "really forcing the front jaw vertical for clamping horizontal sticks up at the top" the vise is not very good in this regard, partly to my poor workmanship and partly to the small diameter of the screws. I'm contemplating designing a thrust/radial bearing made out of delrin to help the situation. If you follow Chris's advice on how he installed the vice you will have better results... I didn't becuase i was in a hurry and thought I would skip rolling the bench so the front was up.

Dave