Twin-screw vs leg vise

[Randy Klein]

A while ago I wrote about a leg vise I made by using a typical quick release cast iron vise on its side and bolting it to the bench leg. I've been experimenting with different bench configurations on this cheap solid core bench before I build a real bench.

If you look at the thread, you can see that it has a few advantages:

1. With no screw in the way, it can clamp straight to the floor. This is useful for long boards and panels.
2. The parallel support bar can be used to support long boards as you plane the edges.

But there were also a few disadvantages:

1. Due to the offset screw, the vise wanted to rotate all funny like. I imagine if you put the pivot point bar through the leg it would prevent this. But I didn't do that.
2. Having to adjust the pivot point for different thicknesses, while easy and not required that often, was kind of annoying.

So this weekend, I made a twin-screw vise to replace the leg vise. I haven't had a lot of time to test it out, but I can see these attributes:

1. Like the leg vise, you can clamp boards/panels less than 25 inches straight to the floor. But the leg vise clamps practically the entire board to the leg, where the twin-screw has only clamping power at the top.
2. Long boards are easily clamped above the screws, very securely.
3. Panels wider than 25" would have to be clamped outside the screws. There is ample clamping power there, but will still need a clamp on the panel's opposing side.
4. The twin-screw sticks out farther and consumes a much larger portion of the bench, than the leg vise. I think this will get in the way for planing, but I haven't decided on that yet. But this may be negated by a much longer bench.
5. Adjusting the screws, while holding the piece, will take some practice and I need to make some real handles first.

I'm not sure which one is more preferred, I'll need more time. I may redo the leg vise with a typical face vise (still turned on its side) instead of the cast iron. And I'll probably try out a shoulder vise as well. Hopefully by then, I'll know what I want...

[Chris Friesen]

My first instinct is that you have too much space outside the screws. As you say the primary purpose for that area is just to clamp one side of a really wide panel...so you could move the left screw almost to the end of the bench and then leave maybe 4-6" past the right screw. That would gain you back some space for planing.

Also, you might consider boring some holes in the leg to take a dowel or holdfast. This lets you support a piece being sawn from underneath while the clamp just holds it in place.

[Randy Klein]

... you could move the left screw almost to the end of the bench and then leave maybe 4-6" past the right screw. That would gain you back some space for planing.

I considered that and I may still do that. But after looking at Chris Schwarz's Holtzapffel, his vise was offset on the leg as well. I thought he did that for 1 of 2 reasons:

1. He was trying to get the left screw as close to the leg as possible and purposely pushed the vise to the right. This would allow wide panels more clamping area to the lower stretcher. Since on the other side of the leg, there is no stretcher, and the bottom side of a panel would be unsupported.
2. The length of his bench (6 feet) dictated it.

I plan on making a 10 foot bench, so that will leave me about 6 feet of "no twin-screw vise" area. So this may not be an issue in the end.