Tailscrew ..... leg vice .......advice needed

Rob Keeble

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GTA Ontario Canada
Hi All

I need some input please and all opinions welcome.

I bought one of these (a lee valley tail screw vice) to use for the main screw in my leg vice on the new workbench.

So i am getting ready to do the drilling and mounting of the chop to the bench and the leg that is going to be used as this vice.

If you take a look at the picture on the lee valley site you see the back end where the screw goes through has a extension to the base. (very difficult to describe what i mean here).

The base is counter sunk on what would appear to be the underside of the side that i was thinking of fitting flat down on the rear of the "fixed leg" part of the "leg vice"

This got me to thinking perhaps i was doing something wrong.

So my questions are (that is if you understand what i am saying)

Which way should i mount this rear essentially screw bearing?

What clearance would you think i need on the screw hole going through the chop. Should it be a snug fit or say a 1/8 clearance all round?

Do i put the "NUT" thats the best term i can think of on the rear of the leg or make a huge hole and sink it into the face of the leg jaw and use the countersunk holes.

Since i am using a approx 1.5 inch piece of Brazilian Oak mounted to the existing leg as the rear jaw I do have the option and was thinking of mounting the nut on the rear of the "leg side jaw" and doing so by countersinking on the face of the jaw and putting quarter inch bolts all the way through. Thinking here being that when the vice pulls up tight the nut is on the other side of the two pieces of wood being clamped together so the nut is not being "pulled out" so to speak.

But i have see the leg vice that i am imitating has the bearing nut mounted in the front face of the leg jaw side they also speak of clearance and the screw running free and only on the nut.

HELP? I am slightly concerned and need some reassurance or alternative thoughts here please.
 
My gut says the "nut" should go on the rear in the position shown in the picture. That is; countersunk into the leg from the rear so that the square mounting plate sets against the leg. Kinda sorta like (sorry for the crude drawing):
 

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Thanks guys thats just what i feared. :( Thanks for the drawing Glenn explains it perfectly. What stopped me is the thickness of the add on leg piece. Its thinner than the nut. Can you see any reason why I could not mount it the other way other than resulting in a narrower opening of the vice by the length of the nut.?

I could also add a block to that area to thicken it up and do it the correct way. Way i see it that would get the thread of the nut all the way through the leg jaw.:huh:
 
That's a good question. I'm planing mine and was wondering the same thing. Is there any reason to mount it countersunk verses turn it around and surface mount it. Rob mentions loss of a bit of capacity, but beyond that?
 
Glen's drawing is the way to go. It is how I did mine. The nut goes on the rear face of the leg. You want to countersink it or so it doesn't freely spin.

Did I understand you to say that the leg isn't deep enough to countersink the nut? I'd just add a block to make it thick enough.

Pictures?!?
 
I don't see anything wrong with mounting it the other way around other than the loss of the lateral support of the countersunk "neck". I would consider grinding the neck down or adding a spacer before I would consider turning it around and losing that support as you describe. JMHO. Are your workbench legs really that thin or is that neck longer than it looks?
 
Thanks all. Yup Carol i think i go that way. Add a block. Glenn has a good point about support.

Bill what a goldmine this place is for information. Thanks for the search and pictures. I see he mounted it the same way i was going to and then says in hindsite he should have done it the other way.

So i will add a block and do it the "right way".

Thanks all.
 
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