# installing metal screw for leg vise



## dpjeansonne (Aug 8, 2009)

I bought a metal screw (LV tail vise screw) to use in my build of the leg vise on a new bench.

I am not sure about the orientation of the threaded nut/flange. There is two ways:
1) I think I saw someone install one by mortising a hole on the backside of the bench leg to accept the nut. This makes the flange face the rear of the bench. Or,
2) Looking at the nut flange it would be easier to reverse it and make the flange face the front of the bench which would not require countersinking the nut into the leg. The screw countersink holes would be backwards but it still can work.

Does the orientation matter?


----------



## knockknock (Jun 13, 2012)

option 1 (recommended):

a) You loose the thickness of the leg from your maximum vice travel/opening.
b) If the nut is counter sunk tightly, it will bear more of any downward or side forces applied to the screw.

option 2:

a) You loose both the thickness of the leg and the length of the nut, from your maximum vice travel/opening.
b) The 4 screws holding the flange to the leg, will bear more of any downward or side forces applied to the screw.


----------



## Smile_n_Nod (Jan 20, 2011)

When I installed the LV tail vise screw in the leg of my Roubo bench, I mortised the nut into the leg. If done correctly, this allows the leg to support the weight of the screw and vise, not just the screws that hold the nut in place.

Because the nut is tapered, you'll want the hole to be tapered as well. I started by drilling a hole with a diameter equal to the narrowest diameter of the nut (near the tip), to a depth equal to the length of the nut (measured from the flange). I then drilled another slightly larger hole over the first that is equal in diameter to the largest diameter of the nut (this hole was only about 1/4" deep). (Note: I drilled these holes with a drill press so they would stay aligned; if you drill them by hand, you'll probably want to drill the larger, shallower hole first.) I finished by using a Dremel tool with a sanding drum to grind out the inside of the hole to an approximate cone shape. The LV vise nut is covered in thick, green paint, so you can jam the nut into the hole, twist it a little, observe where the green paint rubs off on the inside of the hole, and then grind away the wood at that location. It's hard to explain with words, but hopefully this description gives you a sense of what I did.

I can open my vise now to 8"-12" without any noticeable sag because the tapered hole in the leg provides good, solid support for the nut. The screws only have to hold the nut in place and are not forced to support the weight of the nut, screw, and vise. The vise opens almost effortlessly, even without additional support for the parallel guide.

It would be even easier, though, if the LV leg vise nut had a constant outside diameter so we could drill a single hole for it and screw the nut in place. (By the way, I bought longer screws, too; I don't think the ones that come with the vise are long enough for the pine I used in my Roubo bench).


----------



## dpjeansonne (Aug 8, 2009)

Brett
I understand how you accomplished the tapered section. For the remainder of the hole going towards the chop, did you continue the smaller diameter in the rest of the leg or did you use a diameter slightly larger than the screw?


----------



## Smile_n_Nod (Jan 20, 2011)

Yeah, I forgot about the hole for the screw itself. That hole was drilled with the smallest-diameter Forstner bit that allows the screw to pass through. I had to drill that hole from the front of the leg, but since I had squared up the legs pretty well, it was aligned well with the larger holes I drilled from the backside for the vise nut. I reasoned that if the vise sags a little, the hole might support the screw and keep it from sagging even more.


----------

