Good flat surfaces are not as common as you may think they are. 

Do you think your table is good and flat? Try pouring some water on a large container all the way to the edge and see if it spills. Odds are you’re going to have one side lower than all the rest and it will spill over. This issue comes up pretty often at the shop, like when we are casting things like epoxy or silicone. Recently while prototyping, unleveled surfaces kept being an issue, so we got to building a solution.

So, a Table

A flat piece of wood will not be completely straight most of the time. You can check this yourself even.  If you buy a ply sheet of wood and lay it on the floor you will probably notice it won’t lay completely flat on its own, it needs to be held down by something.  A normal table won’t always achieve being flat believe it or not. With a normal table, your tabletop will only be attached along the edges to the legs and or frame, allowing it to bow in or out everywhere it is not attached. So If you tried to pour something on top of a table that is bowing your pour will be tilted slightly. Depending on what you are doing this may not be a big deal, but if you are looking for precision this is not ideal.

So, how do we fix this?

A Torsion Table

The way a torsion table achieves a flatter surface is through several attachment points through the tabletop. The inside frame of the table has a grid, you can think of it as a waffled interior.

If you were looking down on the frame of your typical torsion table it will likely look like this.

With this pattern on the inside, we are able to attach the tabletop to the inside, preventing the wood from bowing away.

Multiuse! Vaccum table!

So we were building a torsion table. And wouldn’t you know it at the same time we were looking into vacuum forming, so then what? Well making the torsion table double as a vacuum table of course.

The idea is that the table could then suction down, enabling it to vacuum bag things as a form of a clamp. Furthermore, in the future, it could be used as a vacuum table for thermal forming with acrylic.

The adjustments needed for this weren’t difficult, just cutting perforations on the tabletop and channels on the rows of wood waffling the interior of the table. You can see this on the pieces we cut out.

Then it was just a matter of assembly and testing out the table. We carefully put it all together, glued and secured with nails to make sure nothing would shift while the glue dried.

We then sanded down the top smooth, leaving it ready for testing.

Testing

To test we used some prototypes we were working on. Two sheets of wood needed to be laminated flat together, perfect to test the table. With the vacuum, we were able to get a plastic sheet to press down the material together and leave it running for about ten to fifteen minutes while the glue set enough to keep it together.

We have not yet used it for vacuum forming, but based on its performance I think it will work. For now, it is handy to have to evenly distribute pressure on things, also a good flat surface.

Ill do my best to keep you all updated on anything we may end up using the table for. Until next time.