Jeff Oberg wrote: "I have managed to source a 6' long, 6" thick, 23" wide slab
of live
oak. So my next project is likely to be a Roubo style bench made of live oak.
I'm not sure where this is going to take me. I'm considering vice
hardware for the bench..."


A couple of thoughts which you are free to disregard. With this rare a slab you
won't want to trim off anything beyond what you absolutely must. I know I
wouldn't. But 23" is very wide for a bench top, maybe too wide if you end up
liking a bench that sits up against a wall. I'd say, don't cut it narrower now,
but don't choose a design that makes it hard to cut it narrower at some future
date. A full-details Roubo design with massive legs morticed through the top
will be hard to re-do. If you choose a simple, fast, cheap undercarriage with
the top held in place by its own weight and by a couple of dowels sticking up
half an inch, then it will be easy to re-do in future and it will be ready to
use sooner now. And you will always be able to do the massive Roubo legs at a
later date if you want. The simple undercarriage also means you won't be stuck
forever with an uncongenial bench height.And don't plan permanently attached
under-bench drawers;
apart from the fact that they don't go with holdfasts, they too would get in the
way of modifications.

Its great to have the 6" thick top, but its also going to restrict you in a
couple of ways. Most styles of vise aren't going to work well with a 6" thick
top, so you would either have to cut away most of the thickness in the area of
the vise, or you would have the vise screw so low that it would rack unduly. You
will probably find that a leg vise is about the only built-in style that will
work well without massive surgery. However, a leg vise has the advantage that it
can be added with relative ease long after the bench is made (especially if you
plan in a leg wide enough to accept one), and this too will help to get a
functional bench into use as soon as possible.


A natural choice for a massive-top bench would be a "Moxon vise" (I hate that
deceptive name, but that's another  matter) or better yet a selection of them in
various heights, widths, and lengths. The (very modern) design which has spread
recently is basically a dovetailing fixture, very tall to get the dovetails
close to the eye (and notice that Chris Schwartz, who has done so much to spread
the modern version with all its faults, is an uncommonly tall man). A lower,
wider design (say, cheeks of 4" square rather that 1.5" x 6") will be more
versatile and also easier to make, and won't tend to rack the way Chris' tall
design does. Don't forget that you can use a clamped-on vise entirely on the
benchtop if the workpiece doesn't stick out below the vise cheeks. And you might
find that other clamp-on styles are useful, like the gunsmith's vise that Bill
Ghio recently posted about.

With a massive top, holdfasts will be one of your mainstays for workholding.
Remember that a holdfast depends for its grip on being at a certain slant when
tapped into place; and that if it is slanted too much or too little it won't
grip. Most recommendations for holdfast holes seem to assume a bench around 2"
thick. For a 6" thick top you will probably need a larger hole, ind it isn't
clear just how much larger. It will be a lot easier to make the holes the right
size from the get-go, than it will be to enlarge them later on. So don't make
lots of holes in your top in places you think may be useful; make one or two,
use them for a while, and then you will have a much better idea of where you
want more holes and what size they should be.

Wow, its a lot more fun planning someone else's bench than it is to actually go
and make something for myself. Ask again in a couple of weeks and I'll have
another, completely different, set of suggestions for you, all of them worth
exactly what you paid for them.

Tom Conroy