In the next few days, I intend to build a 4 X 8′ cutting/asembly table. I plan to use a 4 X 8 sheet of 3/4″ MDF as the top.
When I built my home, I was introduced to a product called “Sturdi-floor” Instead of conventional 2 x 12 floor joist, Sturdi-Floor is a “joist” made by using plywood as the center of an “I” beam and is said to be much more rigid and straight than a 2 x 12 conventional joist.
I am thinking about using that technique in building the support for the table.
Has anyone on Knots built such a table and what is everyone’s opinion of the plan?
Replies
Hi coolbreeze ,
Maybe around the perimeter , that is way overkill imo , even 6" tall will be more than stout .
I built a professional drapery fabric cutting table that was 63" X 144" . I used 8" X 3/4" plywood frame members in the 63" direction and doubled up the perimeter to make it 1 1/2" thick with 4X4 legs 3 on each side , 3/4 plywood top with padding and canvas stretched over that .
dusty
Dusty, I did not mean that what I would do for the table would be anything like 12". I felt I had to talk about 1 X 12 floor joist because I felt folks would wonder about me using 1 X 4 or 6 joist. LOL
I really an considering using the technique. If I do, I would top and bottom out a 4" strip of 3/4 plywood with a dado'd 2 X 4. Seems to me to be a good plan. I just need some concurrance.
Among the things that I find important in an assembly table is a surface that's dead-flat and easy to keep clean.
Have you considered making a torsion box with a melamine top?
-Jazzdogg-
"Don't ask yourself what the world needs. Ask yourself what makes you come alive, and go do that, because what the world needs is people who have come alive." Gil Bailie
The reason I am considering plywood "sturdy-floor" setup is that it shouldn't sag and has a chance to stay flat. I'm also leaning to a Festool with the 108 fence for cutting ply. if I use it for cutting, would I be wise to top with melimine? I like melimine because it is a slick surface. MDF is fairly slick but would not take the use melimine would.
I have to show my lack of experience in asking you what torsion box??
I like your suggestion of a torsion box. When making a surface for vacuum pressing I used 1" paper honeycomb from http://www.vacupress.com so that it would be strong and light. The issue always is a very flat top surface, and I don't think the construction method impacts this too much. The challenge is to make the top dead flat after gluing it up. That requires either very skilled use of straightedge, winding sticks and plane; or a monster wide belt sander. If a torsion box, the surface skins usually are 1/4" plywood, which leaves little allowance for flattening.But I've found that a double 3/4" MDF top 42"x96" would match the twist in the concrete floor supporting its 2x6 frame. So even "dead flat" doesn't always remain so.Ah, the joys of working with wood ...
I use something considerable less grand than a torsion box.
It is basically to sets of saw horses -- 4' long, 20" high. The tops are half lapped to accept 3 2 X 4's, which are half lapped to fit over the horses.
I use this set up to breakdown sheets of ply (with a Festool), and I cut right into the 2 X 4's (about 1/8 to 1/4")
For use as an assembly table, I have three pieces of Birch VC ply which I have varnished -- each is 4' wide X 32". Three pieces make it easy to set them aside to use the thing as a cutting rack. Ordinarily I don't have to, but I do have countersunk holes in the ply pieces so I can screw them down to the 2 X 4's.
This arrangement has the advantage of being able to move it out of the way if I need the space for something else.
If you end up with a more permanent arrangement, people with Festool or the EZ Smart system often use a piece of 4 X 8 insulation as the sacrificial cutting surface. I use 1" thick (3/4" will do) stuff with the aluminium foil.
If you buy the Festool, instead of buying the 108" guide rail, you might consider buying an extra 50" rail with a set of connectors. The saw comes with one 50" guide rail. The guide rails are rather fragile for my taste, and I didn't want a 9' rail that I might kick or bump, and thus bend. If you have a good place to store it, then this would not be a problem.
I ended up with a total of 3 50" guide rails and one that is 30", which covers all my bases.
The connectors, BTW, work very well.
********************************************************
"It is what we learn after we think we know it all, that counts."
John Wooden 1910-
Nikkiwood, I am quite serious about getting a Festool.
I have wondered about the use of the foam under the piece to be cut. Where do you get your foam? Why the aluminum skinned? How long does a sheet last?
I know the Feswood has a good dust collector but how does it handle the foam and aluminum?
Cool
Any sort of foam insulation will do, and there are three types available at any home center: bead board (the cheap white stuff), styrofoam (a little more dense, usually blue or yellow), and the stuff with aluminum foil (even more dense, called polyisocynurate -- sp?). Each is available in 3/4" or 1" -- which is all you need for a cutting surface.I reasoned that the aluminum foil version would stand up better to handling and cutting into it. The styrofoam stuff would probably work just as well. I think I would avoid the bead board insulation, since it is not very strong, and the edges tend to break off as you handle it over time. You're only cutting into the insulation about a 1/4", and this doesn't have any effect on the dust collection. How long the sheet lasts will of course depend on how many cuts you make on it. If you're not using it everyday, I would guess it should hold up for at least a year or two. Remember too, this insulation is realy cheap.......Using insulation for a cutting surface is not my original idea. I first heard about it from other Festool saw users, and it is a fairly popular way to go.********************************************************
"It is what we learn after we think we know it all, that counts."
John Wooden 1910-
Cool,
My local Home Depot has 1" thick foam (pink) in 4 X 8 sheets for $10.28 each. It's in the bldg materials section, usually by the insulation rolls
Lee
Lee,
Thanks for the tip. I will look for it.
coolbreeze,
Several Festool saw owners use foam insulation as a cutting backer. You only cut into it a tiny amount, scoring-cut depth.One of the people who first popularized this idea was John Lucas, who has a great woodworking site with a Festool section.Here's one of his Web pages where he describes the use of foam as a backer material:
http://www.woodshopdemos.com/fest-3.htm
I too have an assembly table. But I wanted it to be height-adjustable - very handy when work ranges from 30" tall buffets to 18" high balnket boxes or smaller. One of the big box stores, I think it is HD, has height adjustable sawhorses. They are sturdy, collapsable and adjustable from about 24" to 36".
Frosty
Frosty, how do you make it adjustable? I have always said that woodworking is 80% problem solving. I have given thought to making the table adjustable. I just have not put my mind to the construction plan.
In what increments does your table adjust?
The saw horses are black plastic. The top section can be raised in increments of 1" - when the legs are folded flat. Once the feet are spread, the height can not be changed.I just went to the shop and checked: the adjustment range is 30" to 37"; they are manufactured by Stanley. I'm pretty sure they came from HD - you can recognize them by the yellow bend of inch increments. They are solid as a rock.Good LuckFrosty
Thanks, Frosty
I printed the message and have it in my file for near future ref.
Cool
I'm on my third 4 x 8 cutting/assembly table. Its 4 x 4 legs and a 2 x 4 frame that allows the top to overhang about 4". I have 2 additional 2 x 4's as cross pieces. I used mdf which was not a good idea so I replaced it with 3/4" birch.
I also bought, from Grizzly, some 4" wheels that lock both ways and they are great. I can move the table anywhere I want it within the area that it lives and the locking wheels prevent the table from moving when I want to do something that otherwise would move the table, planing for example. Its also good to move someething heavy to or from my truck.
Loading a heavy piece of furniture or unloading sheet goods. I just back truck up to the overhead door and move the table in place.
Nothing like not naving to manhandle 4 x 8 sheets of MDF or plywood.
John
I built a 4*8 table from four 25mm sheets of baltic ply. I used two for the top and two for everything else. I cut 150mm planks from the sheets to make a ladder frame and legs to support the top. All the sheets are screwed into the ply edge grain - use modern screws, drill a pilot hole and fix a clamp over the hole while screwing, and it works very well, not a loose screw after 5 years. One sheet screws down onto the ladder frame. I screw up through this sheet into the top sheet, making a 50mm thick 8*4 table. This way, I can easily replace the top sheet if it is damaged. The whole weighs about 250kg, and is flat to within about 0.5mm across the whole asembly. And it folds up on hinges against the wall of my garage on the odd occasion I might actually not be needing it!
Personally, I'd recommend cutting planks from sheet to make straight lines, rather than using engineered I-beam sections, providing you have a saw which can cut straight.
David Marks has offered a tosion box design that I plan to build on a 4 x 4 frame.
http://www.djmarks.com/stories/djm/Torsion_Box_Assembly_Table_94697.asp
Coolbreeze,
I think there a lot of good tables you could make using those engineered joists ( they are often called TGIs ). They come in hieghts down to ~9" (mabey less, I don't know). If you check around w some local lumber yards, or local framing outfits, you might be able to pick up some 8' and under cheap.
H
This forum post is now archived. Commenting has been disabled