Having now sorted out domestic arrangements I have now decided to convert
part of a garage to a permanent workshop and have started making the frame
for a workbench. Any ideas from the team on the best way/material to make
There are those amongst us who went to the store and bought
a solid core door. In our heads we used the thinking that
this would be a good "get by" but after a couple/few years
we joined the fraternity of Door Benchers.
UA100, Door Bencher since 1988...
I've been thinking about using a door -- but a hollow one. Hollow? But,
wait! The reason for the hollow door versus solid is that a solid door
will not stay flat -- that is, flat enough to be a good glue-up surface.
Or that is my concern. A hollow door will stay flat -- in theory, as it is
akin to a torsion box -- and, to keep it from being pierced, I was thinking
of wrapping it with 2" thick wood and then laminating 1/2" mdf top and
So, question: Has your solid core door stayed flat enough for a good
glue-up surface? My thinking is that a hollow-door will stay flatter than
a solid core door.
I am also thinking of the laminated hollow-core door approach as a
stable-flat base for the "Ultimate Tool Stand",
http://christophermerrill.net/ww/plans/UTS/Tool_Stand_1.html rather than
building the torsion box from scratch. Unlike using a solid core door as a
top -- and the frame of the table can help keep it flat -- in this tool
stand the "door" has to stay flat even if unevenly supported. -- Igor
I have used hollow core doors and laminated 3/4 MDF to both sides. My
current bench is 15 years old. I glued up 4x6 D Fir to make a top 33 inches
wide and 7 feet long. I have a pattern makers (Emmert) vise on one end and
two Wilton quick release vises on the other. Before I glued it up I cut
bench dog slots (1 x 11/2) in two of the edges that line up with the Wilton
bench dogs. The top was then run through a wide belt sander (both sides)
which cost me $25 to have done. The bench has been resurfaced twice in 15
years and is dead flat and weighs a ton so it won't move. Total cost back
then was $100. It is a beauty and gets lot's of compliments.
I do use an oil base poly on top so the glue never sticks.
My "solid core" door benchtop has stayed flat for a few years now.
Your idea of using a hollow core door, which uses a principle known as
"stress skin" construction to maintain flatness, should work well providing
you overcome the lighter weight issue (you generally want a heavy benchtop,
which the solid core door gives you) with additional "skins", as you
Let us know how is works out.
I'm thinking that one maybe didn't get baked quite long
I haven't a clue. Back in the day we used to make plastic
laminate tops with 1 1/2" hollow core metal substrates. I
have one of those that's 3' X 5' that I use for an assembly
table top. It's very flat.
In your post above I thought you said you indicated you used a solid-core
door as a benchtop. That's why I asked.
Well, that raises the basic question as to the effective difference in this
application between a torsion box and a typical hollow-core door --
especially after 1/2" or 3/4" mdf is added top and bottom. I don't have
any hollow-core doors in my house to try torquing. I can surmise that 3/4"
mdf as the internal grid in a torsion box could help resist torquing better
than the honeycomb inside a hollow door, but maybe the mdf is
overengineered for this - again, compared to a hollow-core door sandwiched
between 1/2" or so mdf. -- Igor
Sorry about that. I do have the Door Bench and mostly use
it to pile crap on. The assembly table is mostly where most
work gets done. That and the outfeed table for the saw but
I'm working on a New Year's resolution to not be doing
that/leave it alone and let it be an outfeed table.
By the way, I meant to ask, why do you feel it's so
important to have a "supeflat" surface for glue ups? Reason
I ask is I'm pretty certain that most clamps with out do
anything you put into flattening a top. This of course is
not to say I'm recommending that you use the drive way for
glue ups, just that I've never given it much thought/if I do
I'm pretty certain I'd be right back where I am.
As I'm on the early part of the ww learning curve, my concern is based on
some reading & research. For example this article on torsion boxes:
and this one on a rollable tool bench:
There is max's post in this thread which suggests an additional
confirmation of my concern. And, it makes some sense to me, especially
when gluing up cabinet boxes. Anyway, my sense is that there are MANY
variables when woodworking (as with many other things) and so I try to
reduce the variables where I think I can. For example, doing a TS tune-up
to a few thousandths of an inch, even though being off by 100th of an inch
is probably OK when it comes to many TS cuts. If you are asking if I've
had some experience that has taught me the need for a "superflat" top --
not yet. -- Igor
I will frequently glue up stuff on winding sticks. You lay two straight
sticks (key word, straight) on your bench and glue up on top of the sticks.
It doesn't matter if your top is cupped. The sticks work well.
OK, I'm with where you are but I can't help but to think a
thing or two about all of this. Firstly, wooddorking ain't
rocket science but one thing I do know is you ain't born
knowing all the variables that come into play (1).
OK, stop scratching your head and wondering, "Is he about to
go off on some ramble/when can I stop paying attention?".
I'll get there.
Torsion boxes are a great thing but aren't absolutely
necessary (2). I would start with a good and stout work
surface first. Two layers (or for a couple few dollars more
three layers) of MDF will make a fine surface to work from.
To that I would build a good base beneath it. Four by fours
and some aprons/rails going around or full blown cabinets
(storage/adds more mass), what ever you want/need. In the
end you are concerned about bowing/cupping/twisting you can
shim from underneath/pull up/push down until the top is
flat(ter). The point here is to have something that won't
go rolling around the floor.
As for tolerances, I'm of the opinion that you take a
string, pull it taut across the surface and get it trued up
by eye. Anything after that is working in the hunnerts of
an inch and not worth finding yourself puking up in the
corner of your shop over.
Now, something to think hard on, to "successfully" build a
torsion box you'll find that it's better/easier if you have
a flat surface to start with/build the torsion box on. I'm
not saying it can't be done without it, just that it will be
harder/you'll be fiddling with it a whole bunch more.
I'm going to interject a thought here on box assembly.
*Normally* a box isn't too huge. We occasionally do a big
item though really most projects aren't. When you assemble
a box you will/should be checking the parts and pieces as
they relate to each other, not to the assembly surface
below. In other words, are the sides square to the
bottom/top? You can have a gap big enough to drive a Buick
through in the table below but that doesn't matter as long
as you are squared up.
This is not to say it doesn't help/you shouldn't care, you
really should, but...
Now, having said all of that, boxes flex/have some give
during constriction. An example. You can put two sides
together along with the tops and bottom and depending on the
size of the box you can be out of square by a half an inch.
It's probably not going to matter because you'll go to fit
the back and pull it all to true during that phase of
Please do not think for a minute that I'm advocating bad
construction/it'll be fixed in the end, just that this is
one of the variables you will be thinking of during
There are two arguments on machine set up. One is that wood
moves enough to make any sphincter puckering machine set up
not worth the time and then there's the "I would prefer to
remove as many variables as I can from the equation/it's my
$150 and I bought a TS-Aligner JR so go piss off". I prefer
the latter over the former though I can't tell you that all
my processes are at zero, just that I'm as close to zero as
I can get so I'm not off in the corner of the shop puking my
(1) Whole books have been written on the subject/a life's
time could be spent studying it/I can't right off hand think
of a better way to waste my spare time.
(2) Torsion boxes are best suited for spanning long
unsupported lengths or when something needs to be light(er)
weight. They are fun to make and in the end you'll find
yourself showing them to anyone who will stop for three
minutes to hear you go on about them.
UA100, who really is agreeing with you more than you might
think but thinks that "dead flat" isn't anything to lose
(1.) "A man walked along contemplating suicide; at that very moment a
slate (roof) tile fell and killed him...."'
(2.)"Current plate movement can be tracked directly by means of
ground-based or space-based geodetic measurements; geodesy is the
science of the size and shape of the Earth. Ground-based measurements
are taken with conventional but very precise ground-surveying
techniques, using laser-electronic instruments. However, because plate
motions are global in scale, they are best measured by satellite-based
methods. The late 1970s witnessed the rapid growth of space geodesy, a
term applied to space-based techniques for taking precise, repeated
measurements of carefully chosen points on the Earth's surface
separated by hundreds to thousands of kilometers. The three most
commonly used space-geodetic techniques -- very long baseline
interferometry (VLBI), satellite laser ranging (SLR), and the Global
Positioning System (GPS) -- are based on technologies developed for
military and aerospace research, notably radio astronomy and satellite
(3.)"You can observe a lot just by watching."
Well, at his site he does say this: "I am a designer, woodworker who
specializes in high-end projects." If his clients pay enough for him to
have granite work tables, I s'pose so. (As if the photos of his work did
not provide enough evidence.) More power to 'im. -- Igor
From your earlier post in this thread,
Plamann thinks a flat surface is good. <g> Wanted you to know you weren't
OTOH here are a pair of Workmates.
(Yes, I have spent a lot of time at TP's site. ;-)
Well, they're not free, but if you have a quarry nearby, sometimes
they sell granite sheets with defects for a discount. But why not
just glue up a thick hardwood top and plane it down periodically? I
can't imagine that your benchtop flatness needs to be within .001"
unless you're making jet engines out of maple or something. I made do
with a bench made of 3/4" pine plywood and some 2"x4"s from the Borg
for several years, and it worked all right for just about everything.
I had to screw it to the wall to keep it from sliding around when
doing certain things, but once that was done, it was just fine- and
it's still flat, even after being moved a couple of times. Total cost
was about $40.
Aut inveniam viam aut faciam
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