Torsion box lattice sizing - Woodworking Talk - Woodworkers Forum
 
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post #1 of 6 Old 08-24-2015, 10:25 PM Thread Starter
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Torsion box lattice sizing

I am building a couple of outfeed/assembly tables, and plan to build a workbench as well. I plan to use torsion boxes for the work surfaces. However, I can't find a lot of information on sizing the webbing. For example, I have a 30"x60" top, 1/2" Baltic birch skins. I will likely use poplar around the outside as the outer edge of the webbing. I am making the webbing of old 1/2" ply cut into 2" strips. My question is how many webs I should use. Should I space them 5" apart? 10"? 15"? If there are some typical dimensions or a good rule of thumb, that would be great.
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post #2 of 6 Old 08-25-2015, 02:16 AM
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sounds about right to me

My outfeed table is 120" X 30" and I used 3/4" pine for the webs, about 10" or so centers with 3/4" particle board skins.

http://images.search.yahoo.com/yhs/s...&hsimp=yhs-006

Here's mine:
I made this one from 2 pieces of 3/4 particle board 10 ft x 30" for counter tops. It's also got another 3/4" piece on top for a replaceable work surface. So far I haven't needed to flip it over. I sealed it with shellac which make for a really smooth slippery surface.... not always good when trying to hold something down with a clamp.

It's very strong, heavy, level, flat and stable. I flattened out the first 10 ft sheet and then glued the sides on using a 10 ft long 2" x 2" aluminum tube for straightness, one side at a time. I then added the center long strip and then filled in between with short ones, all 3/4" stock ripped to the same dimension, about 2 3/4". When everything had set up I coated all the exposed edges and then plopped the top on and used everything I had to weigh it down as well as clamps along the edges:
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The answer to your question will only be as detailed and specific as the question is detailed and specific. Good questions also include a sketch or a photo that illustrates your issue. (:< D)

Last edited by woodnthings; 08-25-2015 at 02:18 AM.
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post #3 of 6 Old 08-25-2015, 03:40 AM
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When I built my 3'x3' table I went with a 3 inch square grid. No real reason, but its worked pretty well for me so far. I've yet to come across any hard and fast rules, but my intuition says that somewhere in the 3 to 9 inch square grid range is the sweet spot for a 1/2 to 3/4 ply web. If you're using 2x4s like wooden did, you could likely get away with a larger spaced grid die to added stiffness of the material

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post #4 of 6 Old 08-25-2015, 07:12 AM
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not 2" X 4" ...

Quote:
Originally Posted by epicfail48 View Post
If you're using 2x4s like wooden did, you could likely get away with a larger spaced grid die to added stiffness of the material

I used 3/4" ripped to 2 3/4" wide... as stated above....

....."and I used 3/4" pine for the webs" .....


" all 3/4" stock ripped to the same dimension, about 2 3/4"."



You can tell from the photos it's not 2" X 4" stock.

The answer to your question will only be as detailed and specific as the question is detailed and specific. Good questions also include a sketch or a photo that illustrates your issue. (:< D)
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post #5 of 6 Old 08-25-2015, 08:56 AM
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I recently built one. 5/8 MDF with grid around 8" square for a 96"x36". Has worked out really good so far.

I think more important than the grid size is what you build it on. Ensure its flat so the torsion box is flat.
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post #6 of 6 Old 08-25-2015, 09:18 AM
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I built a 5' by 10' torsion panel screen for my home theater room. It's hinged at the top to access the storage shelved behind it. I wanted something that was strong, yet not to heavy. I also didn't want it to be very thick.
So here's what I did;

- Luan panels for the front and back
- 1"x3" hickory laid flat
- made a boarder ("frame") around the entire perimeter , and (only) three rows in between.

When it's raised perpendicular to the floor, there is very little bow across the 10' width.
Over all thickness is just a hair over an inch. Weight is a bit heavy, but I am able to "bench press" over my head.

That would definitely be strong enough for feed tables, but not for a workbench.

Hope that helps, and gives some perspective.
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