torsion box router table anyone

[Adrian Anguiano]

I have an incra router table system and was doing some dovetails and ran into issues because my table dips in the middle. Incra brand too, but I got it used from a neglected owner.

So I was wondering if anyone has made a torsion top for a router table.

Pictures welcome

[Doug Herzberg]

I made something like that in the form of a wing for my table saw. I ripped some 3/4 plywood into 3-1/2" (or so) strips for the framing and used a sheet of melamine surfaced 3/4 mdf for the top. Edged with some oak I salvaged from a flooring job. Routed in for a cheap router plate and some T-tracks for a fence and miter slot. I haven't checked for flatness since I put it on the saw. I don't do a lot of precision work with it, but I haven't had any problems so far and don't have any reason to suspect that it has moved.

If I had it to do over, I would probably make a thicker top and close the bottom to complete the box. I didn't really pay a lot of attention to design and I'm not sure I even knew what a torsion box was at the time. I'm sure you can do better. Good luck.

[ian maybury]

I've made a rip table for my table saw by similar means - 3/4 in birch ply top and bottom skins (thick to prevent the strips telegraphing through) glued up over roughly 2 1/2 in wide strips of the same and then skinned with formica top and bottom. Very rigid, very flat and stable so far after about six months.

That said I have an Incra table which has stayed dead flat too, but it's in a dry shop, and is well supported with lots of steel angle and a birch ply dust chute from underneath. It started with a very slight curve which resulted from my storing it leaning against a wall, but pulled straight on assembly with no problem. The core is MDF, so it seems like damp conditions and minimal support would likely to lead to sagging. Screwing down to an irregular or flexible base cabinet probably wouldn't help either.

It's basically a decent table though. Perhaps yours would pull straight by similar means Adrian.....

[HANK METZ]

That type of construction is all I use for my saw table tops. It's stability and load- bearing characteristics are out of this world, and construction is easy, usually with just scraps laying about the shop. Here's a video demonstrating it's construction- adapt to your needs.

- Beachside Hank
Improvise, adapt, overcome; the essence of true craftsmanship.

[pat warner]

So I was wondering if anyone has made a torsion top for a router table.
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Very hi strength to weight ratio but not something that can be counted on to start out flat, say + or -.004-5". I would not use it for joinery; not an issue for decorative cuttings or any cuttings where variability can be tolerated.

[ian maybury]

You're probably speaking from experience Pat, and i'd agree. That said (and it took an lot of checking, sweating and care) I had good luck in producing a very flat table for my Hammer K3 saw as in the photos below. It ended up well within the limits you listed measured with a straight edge and feeler gauges. Not sure exactly how well it's stayed that way 6 months later - I'd have to check - but it seems fine. The risk is that it could develop some rippling over the open areas - even with 3/4 in top and bottom skins. I'm hoping that the birch ply should be relatively stable.

It's skinned with formica which probably helps slow any changes in moisture content. Plus the skins are phenolic coated which might help too. I U turned and put formica on the top (and on the bottom to balance the construction) because the phenolic seemed a bit soft and easily dinged.

What is clear is that if there's to be any chance of getting it flat in the first place the birch ply has to be top quality, of uniform thickness and not have any ripples or anything in it. Plus when gluing it up a reliable flat surface and loads of uniformly distributed weight are needed. I used a liquid polyurethane adhesive (which also bonds well to the phenolic if you first solvent wash and then sand it) as i was wary of a white/yellow glue creeping...

ian


low res ts ls overall view.jpglow res k3 table honeycomb.jpglow res k3 table glue up.jpg

[Adrian Anguiano]

Ian I'm sure I could probably shim the middle to make it flat but I was thinking of creating a cabinet anyways for it to sit on so it would be a good time to start from scratch.

Pat, I'm not sure why a torsion top would not stay flat. If its made of MDF then how would that be worse than just an MDF router top?

[Kurt Cady]

I built mine out of mdf. 1.5" thick. What I did different is put in specially located supports to directly support all four edges of the router lift. No real stress goes into the table from the weight of the router.

[pat warner]

If its made of MDF then how would that be worse than just an MDF router top?
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Because you've 25 elements to manage vs. 1. Which is easier to control/create & maintain?

[Bob Potter]

This is for Ian Maybury
Not trying to start another thread but I noticed that you have an Incra L.S. fence on your Hammer saw. Did you not like the fence that came with the saw?

Thank you, Bob

[Thomas Hotchkin]

Adrain
Take a look at this post. Tom http://www.sawmillcreek.org/showthre...uter-table-top!

[ian maybury]

It was a little accidental Bob. I bought the TS LS to fit on a Robland combo, but eventually decided to upgrade to Hammer separates.

I'd by then figured that I liked the idea of the Incra positioner (the ability to set and especially to return to or to use the clicker to creep up on a given dimension). The DIY rip table followed because it made mounting the fence easier, and seemed nicer than the perfectly functional stock sheet metal table. The latter has a reduced area outboard section which didn't lend itself to mounting the back rail of the Incra. It seems fine, and is way ahead of what I had before - but so far hasn't done enough work to be really sure.

The very early (1990s) Hammer saws were criticised a bit for their rip fence, but so far as I know the current model is rock solid and gets excellent reviews.

Feel free to PM if you want to discuss more.

ian

[Jim O'Dell]

Adrian, I built a grid out of 3/4" ply, with 3 layers of MDF over that for my router table, but didn't skin the underneath side. I did not make a full torsion box because of the issue of the chamber to house the router. But on retrospect, could have with that one grid enlarged to accommodate the plate size and routed out the opening for the underneath side. Remember the 2 cabinets on the west side of my shop for the infeed/outfeed of the slider? Both of those are Torsion boxes, as are the extension tables for both table saws, the mobile outfeed table and the new assembly table. One word, if you decide to do this for the router table, and I think it would work fine, use your TS to assemble it on. My first attempt at the new assembly table was done on the base I built for it...big mistake. I destroyed 65 bucks worth of MDF. The replacement was built on the 691 and came out perfect. Come by if you want to look at mine again. Jim.

[Bob Potter]

Thank you Ian
I have an Incra L.S. on my table saw and also love the repeat ability

Bob.

[Darcy Forman]

I have an incra router fence positioner, and a Incra router lift. I built my own table from scratch which is 32" wide by 48" deep. I built my own top out of two layers of MDF glued together. Then covered both sides of the top with formica. Then I built a torsion box out of 3/4" by 2" oak. with truss stips spaced every 6" with a long truss running down the middle. It was a little overkill I admit. I think you could walk a D8 over it with no issues. The result was no sag issues at all. Was a little bit of work and my table weighs a ton, but I enjoy the quality of work it produces.