Torsion Box as Router Table Top to Accept Router Lift

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Forum topic by BigMig posted 10-15-2017 05:53 PM 3740 views 0 times favorited 7 replies Add to Favorites Watch
View BigMig's profile


474 posts in 3389 days

10-15-2017 05:53 PM

Topic tags/keywords: router table top torsion box router lift ribs baltic birch

I want to mount a router lift in a router table top and I can’t spend the dough for a premade router table top. So, I feel like making one is a viable option. And the “torsion box” seems like it could be a great way to go to handle the weight of a lift plus router.


1. Am I correct in that the torsion box will work well as a router table top using a lift?

2. What thickness should the “skins” be made of? I assume they will be from Baltic birch, and the top one laminated with Formica/Wilsonart, etc. to ensure that material slides well.

3. What should the internal ribs be made from? Hardwood? and if so, what dimension? 1” x 1” for example? I have some baluster material that’s straight, about 1” square, and could make good ribs. Or, do I need something more dense – like oak?

Lastly, all the plywood I get tends to have a slight bow to it. In making this top, I assume I’ll place the curves in opposition and screw/glue them to the ribs to “cancel” each other out. Will this be an effective solution to slightly bowed plywood?

Thanks to all!

-- Mike from Lansdowne, PA

7 replies so far

View Rich's profile


5619 posts in 1365 days

#1 posted 10-15-2017 08:46 PM

There shouldn’t be a problem with a torsion box table top. Regarding dimensions, thicknesses etc, I’d recommend getting your lift first, then build the box to fit it.

-- Half of what we read or hear about finishing is right. We just don’t know which half! — Bob Flexner

View tmasondarnell's profile


130 posts in 2565 days

#2 posted 10-15-2017 10:10 PM

Is there a particular reason you are thinking about a torsion top?

I doubled up 2 layers of 3/4” MDF (glued and screwed), laminated it with some white Formica and called it good.

My concern with a torsion top is that the router will transmit vibration from the lift to the box. You will need to do some fairly significant reinforcement around the area for the hole for the lift.

View ArtMann's profile


1480 posts in 1591 days

#3 posted 10-16-2017 01:51 AM

1. I have made a router table torsion box and it works extremely well.

2. I used 1/2 inch Baltic birch top and bottom and I would recommend it. You could use a cheaper material if you are planning on using plastic laminate on the top and bottom. I finished mine with several coats of polyurethane and it has not worn excessively. One word of warning. If you laminate the top, you really need to laminate the bottom too. That will go a long way towards preventing warp.

3. The internal material isn’t very critical. I used MDF on this project because I didn’t care as much about weight. I also built an 8 foot long by 24 inch wide torsion box shelf that supports about 300 pounds in the middle with no supports and I used 1/2 inch plywood for the grid spacers because it is so much lighter than MDF. Hardwood is completely unnecessary unless you have lots of it to spare. I used 1 inch separation between the top and bottom of my router table and I thing the spacing was 4 or 5 inch squares. That will yield a very stiff and strong table.

Some people prefer a slight crown where the bit goes through the table but I like it to be as flat as I can make it. If I were building another table, I would try to locate flat plywood. I would build it on a very flat surface like a table saw or big flat workbench. I didn’t use screws to secure the skins. I used an 18 gauge brad nailer and lots of glue. I don’t know if you will have time to apply the glue over the whole grid and then drive screws through the skin fast enough to prevent the glue from setting up prematurely. Screws are not necessary for strength and are not desirable in this application my opinion.

Edit: I was just reading tmasondarnell’s post and he makes a good point about using MDF. I built my torsion box table top as a torsion box because it is a lot lighter and I designed my table to tilt up at the front. If you don’t need the lightness of a torsion box, there are other ways to make a good router table.

View Fred Hargis's profile

Fred Hargis

6245 posts in 3269 days

#4 posted 10-16-2017 10:52 AM

I wouldn’t go torsion box. Besides being more work, it’s also a little thicker than the 2 pieces of MDF…or 1/2 of a solid core door (my top). If you do the solid top thing, a good support gridwork under it will keep it from sagging, mine is 15 year old and still as flat as the day I made it. I agree with laminating both sides, though there are those who see it as overkill. Mine sits on a cabinet with that supporting grid and nothing but it’s weight holding it in place. there are cleats in each corner on the bottom of the top to keep it from sliding around (this is a Norm type cabinet).

-- Our village hasn't lost it's idiot, he was elected to congress.

View Redoak49's profile


4743 posts in 2764 days

#5 posted 10-16-2017 11:03 AM

I think using two 3/4” MDF or Baltic Birch would be better and cheaper. My router table is made of two pieces of MDF with Formica on top. I used Formica that was a solid light color that I can write on. I mark the fence location and other things and easy to clean off.

View BigMig's profile


474 posts in 3389 days

#6 posted 10-16-2017 11:45 PM

Thanks to all for your thoughts and ideas. I am considering the torsion box because I have read that MDF can sag – and in fact, I’ve had it happen on a top I made a few years ago. Perhaps the sagging on my table occurred because I installed t-tracks (in routed slots) that the fence attaches to. These run from the back and about halfway to the front, and these sides drop off (slightly).

The T channel I’ve used is from Rockler and it’s 3/8 thick – so embedding it in 1/2 ply doesn’t work very well. But it could work if there were a “rib” underneath the skin of Baltic ply.

Also, I could use a fence that runs on hardware that attaches to the sides of the table and eliminates the need to embed t track in the top for the fence.


-- Mike from Lansdowne, PA

View Loren's profile


10477 posts in 4423 days

#7 posted 10-16-2017 11:51 PM

Sag control can be as simple as screwing some
angle iron to the bottom.

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