Veritas 24" twin screw vise vs. dead man??

[kooshball]

Ok, I know some of you have the Veritas 24" twin screw vise; so is the assumption true that unless you are trying to support an entire tree that a dead-man becomes unnecessary?

I know the official answer is "it depends" but give me some context as to what you have successfully secured vs. what still needed additional support.

Thanks!!

 

[bigcat4t9r]

The Schwarz held like a 10-11' board on edge with his twin screw. On my Holtzapfel, I can always use a holdfast in the other leg as a board jack.

I've plane 8'+ boards on edge with no issues.

 

[cptully]

No experience, but having taken Statics and Dynamics in college, one point of support is fine for short cantilevers, but for longer ones even a small down force will over come surprisingly large clamping forces. Take as an example the center lug nut on a 1960's VW Beetle. My dad one time had to get one off and found that it was frozen... After breaking his 1/2 Craftsman breaker bar and having it replaced with a 3/4" breaker bar, he slipped a 6 foot iron pipe over the handle of the breaker bar and stood on it - the nut did not break loose, the car tipped up instead!

Based on my experience with my 5" bench vise (you know the kind that sits on top of the bench and swivels on it's base), I can clamp, for example, a piece of copper pipe in the vise to saw it off, but if I try to get the saw more than 3-5 inches from the vise I have problems. If I have more than 3-4 feet of pipe I find I have to support the other end or I have troubles... Not exactly the same thing but my gut feeling is that you will be happier with a dead-man than without.

Chris

 

[froglips]

From my reading/viewing on that topic, a sliding deadman offers support under things that would not fit in a twin screw. (yeah,stating the obvious).

Say you wanted to edge plane a large carcass or long board (say for tongue and groove).

I think you'd find a leg or twin screw holds the work against the horizontal forces and the deadman against the vertical.

It is a moot point if your piece can be worked in the twin screw. But for anything longer or wider, the deadman seems a great option.

For some ideas, I found this podcast from the Logan Cabinet Shoppe to clarify workholding. He uses a front apron in stead of a sliding deadman, but in conjunction with a twin screw.

http://logancabinetshoppe.weebly.com/1/post/2010/05/episode-23-workbench-work-holding.html

Jim

 

[bigcat4t9r]

I agree that a deadman would be useful. Scharz's Holtzapfel build was worked to include one but he found that with the strength of the twin screws (wooden ones) that he didn't need it and never added it.

Personally, I like not having to move it around to get at my shelf under my bench. YMMV.
My $0.02.

 

[kooshball]

Thanks folks. Maybe I will try and save a few pennies and go with a cheaper vise but with a deadman in the event that I need that extra support.