Another Workbench Question

[David Castor]

I'm slowing building up a workbench top and building up a lot of hand planing practice hours. But I have a couple of question regarding design of the base.

I plan to use a Jorgensen quick-release vise as an end vise (and another as a face vise). To use this Jorgensen as an end vise, the top will need to overhang the base on that end by about 16 inches in order to not hit the top side stretcher. I'm wondering if this much overhang (cantilever) is an issue? The top is Douglas fir, about 3-inches thick (assuming I don't plane it away trying to flatten it) , 24 inches wide x 72 inches long.

If I lowered the top stretcher about 4 inches, the vice screw and support rods would clear it. But in all of the designs I've looked at, this side stretcher is always right at the top, so I figure there must be a reason. Is it best to keep the top side stretcher right at the top of the base?

The other end of the benchtop will need to overhang the base by 11 or 12 inches to allow for installation of the face vise, so I'm concerned about overall stability and rigidity as the base length shrinks in relation to the top.

Thanks,

Dave

[Jim Koepke]

The overhang is a matter of leverage. Too much overhang on the face vise end will tend to cause the tail end to lift off the ground when planing longer boards. Of course if the weight of the top at the tail end is enough, it will hold itself down when planing.

I just looked up > Jorgensen quick-release vise < and did not find one that looked to need 16" of space. When some wood is added to the face it will take a little off the total length of screw and guides under the bench. Lastly, would it be possible to bore some holes in the stretcher to for the screw and guides to pass through?

I think the reason for a stretcher being at the top is to support the top between the legs. Many of the articles I have read indicate this is the area one wants to use when chopping a mortise or dovetails.

Another thought is some use a pin in the center of the stretchers to hold the top to the base. This allows for wood movement in the top without any force being transfered into the base.

jtk

[Jessica Pierce-LaRose]

The larger of the two Jorgensen quick release vises (http://www.leevalley.com/US/wood/page.aspx?p=65572&cat=1,41659) requires 17 3/4" inches for the guide rods - maybe he's added a chop that's an 1" and 3/4"?

What's the design of your bench? The longer your bench the more overhang you could get away with before things get less stable, and the thicker your top, the less you need to worry about how stretchers are placed, and the more resistant the bench would be to deflecting if it has a long unsupported span in the overhang.

Looking at my Jorgensen vise, I'd be tempted to go with what Jim recommends - simply drilling holes through the stretchers to allow the rods and screw to pass through. Make sure they're oversized enough to allow the rods to pass through without binding if things move a little bit. May want to bump up the thickness of the stretcher to compensate for having three decent size holes in it.

It makes the geometry a little weird, but I've seen small benches where one leg was moved in a bit to help make enough clearance and overhang for vises, the other leg pushed back out. Any stretchers were then going diagonal, of course. Lets you get enough overhang to mount the hardware you want without sacrificing the stability of a small bench.

[Sean Richards]

Hi Dave,

I use a quick-release style vise for a face vise (very unfashionable I know) and it is mounted with the guide rods and screw through holes in the front apron - this is a pretty standard way of mounting them. Maybe you could post a quick sketch of your bench design?

Sean

[David Castor]

Thanks for the responses. Yes, I have the large Jorgensen (10") vise. The 16" clearance is probably conservative. I figured to add a wooden jaw, but let in the back portion of the vise into the end of workbench. I did think about putting holes in the top apron as another alternative. I'll definitely consider that. The bench will be about 72" long and 23" wide - the top about 3" thick.

I'll plan on keeping the top stretcher at the top. I guess I need to sketch up a couple of alternatives. Someday the top might actually be finished and I'll have to make some decisions on the base. 8-)

Dave