# Building own router table



## the_nite_owl (Oct 19, 2009)

Hi everyone.
First time post in these forums. Just getting into more detailed woodworking and trying to improve my knowledge and tools.

I am trying to make my own router table and am having a problem with flatness.
The table is going to be about 32" by 42" to fit the top of the steel frame my table saw came packed in. 
I cut two pieces of 3/4" MDF to size and glued them together screwing them together from the back side to help keep them tight while drying but at some point during the process they warped on me and I now have a very heavy thick slightly curved slab.

Can anyone reccommend some good techniques for making certin I end up with a nice flat surface before I attempt this again?
Or is there a better material or combination of materials for me to work with?
The only really flat surface I have to work on is my table saw which is granite topped so should work well as a reference surface. I have to buy a bunch of clamps if I need to clamp down to the table saw though and the dimensions for the table are a bit wider than the table saw.

Suggestions appreciated.


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## bobj3 (Jan 17, 2006)

HI 

Try it one time but DON'T use any screws,,the screws lift the MDF up and you will little speed bumps that can't be compress down..

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the_nite_owl said:


> Hi everyone.
> First time post in these forums. Just getting into more detailed woodworking and trying to improve my knowledge and tools.
> 
> I am trying to make my own router table and am having a problem with flatness.
> ...


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## xplorx4 (Dec 1, 2008)

Greetings and welcome to the router forum.


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## TRN_Diesel (Feb 24, 2009)

If you drill MDF while they are clamped together you will have to flip the top piece over and the use a small countersink bit on the other side of the exit hole to get rid of the "bump". 

It is time consuming but you will find it will allow the two pieces of MDF to mate nicely and thus produce a flat top. (Popular Wood Working had a good video showing this technique while building a work bench with a MDF top made of two pieces of 3/4")

The other thing you could do to ensure a flat top is to build a Torsion Box for the top of the router table. (Wood Whisper has a good how to video on this torsion box build)


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## Cassandra (Mar 15, 2006)

Hi Nite Owl:

The technique that I used when gluing my 3/4" MDF pieces together was to essentially build the core of the torsion box, using screws as height adjusters for the long pieces. (I had jointed the poplar pieces before making the frame.) Using a Tilt Box inclinometer, I got all the long pieces level with each other. This provided a flat "surface", with the frame pieces about 10 inches apart.

From what I have read, here and elsewhere, screws are best kept away from MDF. As Bobj and Dan have said above, screws cause bumps that need to be dealt with. Best to deal with them before they occur.

When I get home tonight, I'll post a pix or two.

Cassandra


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## curiousgeorge (Nov 6, 2006)

Another suggestion; Use contact cement to laminate the two pieces of MDF together. You just have to be sure the two pieces are oriented the way you want before contacting by using stickers between them. With this method there is less moisture than regular glue and no screws are needed. Simply place on a flat surface and place something heavy on top until cement has set. At least that's what worked for me.


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## Cassandra (Mar 15, 2006)

Hi Nite Owl:

Well, I'm home and as promised, have uploaded a couple of pix.

In the first picture (cr_000.jpg), one sees the frame that I built to support the MDF core. The two outer long pieces fit snugly in the two cross pieces. The third long piece sits a bit loosely in the cross pieces. If you look at the cross pieces near the long pieces, you'll see a screw in each corner. These four screws allow me to level the two outer long-pieces, with respect to themselves and to each other. The center long-piece is shimmed into a level state with the outer two long-pieces. Simple but effective.

In the second picture (cr_001.jpg) one sees my MDF core clamped, after a generous coating of PVA glue. This technique worked well for me.

A side benefit of this technique is that the jointed poplar used for the cauls/frame will be cut and used to make the permanent mounting frame for the router table top.

Cassandra


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## Dr.Zook (Sep 10, 2004)

Welcome to the RouterForums Trent.


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## BigJimAK (Mar 13, 2009)

curiousgeorge said:


> Another suggestion; Use contact cement to laminate the two pieces of MDF together. You just have to be sure the two pieces are oriented the way you want before contacting by using stickers between them. With this method there is less moisture than regular glue and no screws are needed. Simply place on a flat surface and place something heavy on top until cement has set. At least that's what worked for me.


That's what I did too on my 30x52 (34x56 before trimming). I had a 30x60 folding table with a MDF top that was very flat to work on, so all I did was place weight on top. It worked great!

Be caseful not to overload the contact cement though. I did in one place and it too a bit of clamping and time for the cement to shift enough to become completely flat.


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## the_nite_owl (Oct 19, 2009)

Thanks everyone for the suggestions. I am going to make another attempt this evening.

Cassandra, what is the point of the torsion frame for this application, is it just to provide a solid flat surface to setup and glue the MDF together or is it intended to become a permanent part of the table itself?
My table saw is a good flat surface to do the gluing, I just need to make sure everything stays flat while it dries.
If pressure is applied against the top of the MDF while the contact cement dries, will it cause any type of spring back of the MDF when pressure is released? I would think the MDF is stable enough but I am not an experienced wood worker.

Once the MDF is ready I will be laminating both sides to provide a smooth surface on top and to help keep it flat.


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## bigmacattack (Oct 1, 2009)

The first on I built, I didn't use screws either.. Rather, I glued the pieces, and set it to dry between the left over 3/4 MDF between two more pieces and used yard decorative bricksfor press weight to keep them level while the adhesive set up.. Also remember not to let any other moisture than humidity afterward to get to the MDF.. This will definitely give you buckling and bumps which will make it impossible to use...


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## TRN_Diesel (Feb 24, 2009)

the_nite_owl said:


> Thanks everyone for the suggestions. I am going to make another attempt this evening.
> 
> Cassandra, what is the point of the torsion frame for this application, is it just to provide a solid flat surface to setup and glue the MDF together or is it intended to become a permanent part of the table itself?
> My table saw is a good flat surface to do the gluing, I just need to make sure everything stays flat while it dries.
> ...


A torsion box adds rigidity to the table top and thus prevents warping and sags in the table top. I have added a link below which outlines the premis behind the design and shows how to make one.

18- Assembly Table Torsion Box | The Wood Whisperer Woodworking Video Podcast and Blog


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## Cassandra (Mar 15, 2006)

Hi Trent:

When I designed my table and cabinet, I incorporated a frame on the bottom of the laminated MDF core. This was to provide stiffening long-term to the core. Not really needed, since the core is 1-1/2 inch thick, but the frame also provides the means of fastening the top to the cabinet. Dan's comments are right on the money here. 

The idea for my using a frame came directly from Bill Hylton's book _Woodworking with the Router_. 

Since I was going to build the frame, after jointing the pieces, it wasn't much of a stretch to realize that before cutting the frame member, I could use them in the fashion I have used. Two birds, one stone sort of thing.

As for using contact cement between the MDF layers, I haven't. I use PVA glue, which has worked well for me on the top.

Cassandra


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## the_nite_owl (Oct 19, 2009)

I like the idea of the torsion box but in my case I will be mounting directly to a steel frame that is already at height for what I need. For the time being I will have to rely on the thickness of the MDF to keep it flat. Once I have the router plate on hand (aluminum plate front WoodPeck.com) and a router installed I will be able to determine how best to support the table from underneath to prevent the middle from sagging from it's and the routers suspended weight.

I will be inlaying a combo T-Track/Miter channel across the width of the table and some T-Track to mount the fence to. I have no yet come up with a design for the fence. I do not have enough router table experience to know what will work best for yet but it seems basic enough in design that I can upgrade it as needed.
I will need to build some sort of dust collection under the table but I need to see how the router/plate/table are going to work for me to know what I can get away with without causing myself a lot of extra work.


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## dodo (Sep 15, 2009)

hello , I'm also new in this forum , and I'm also bulding my first router table.
Form my expirience , It's almost impossibile to glue two pices of 3/4 MDF or HDF or other material with help of the "home tools " and get realy flat surface
( I tried to make the fance that way - big mistake)

I* strongly recomend to use 30-40mm (1and1/2") beech plywood as the material for the table*If you can afford you can buy Phenolic resin plate , then you can reduce the thickness of tha table plate to 15-20 mm (3/4") , but it's realy expensive stuff


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## the_nite_owl (Oct 19, 2009)

dodo said:


> hello , I'm also new in this forum , and I'm also bulding my first router table.
> Form my expirience , It's almost impossibile to glue two pices of 3/4 MDF or HDF or other material with help of the "home tools " and get realy flat surface
> ( I tried to make the fance that way - big mistake)
> 
> I* strongly recomend to use 30-40mm (1and1/2") beech plywood as the material for the table*If you can afford you can buy Phenolic resin plate , then you can reduce the thickness of tha table plate to 15-20 mm (3/4") , but it's realy expensive stuff


I did manage on the second attempt to get a nice flat surface but only because I had a nice flat granite surface to clamp down to. You really need to have a dead flat surface to start with.

That beech plywood would certainly be a lot lighter than than the 3/4" MDF but so far my table is coming out pretty good.
I have made a number of newbie mistakes as I go. The mitered corners of the hardwood edging is not perfect and I mis-measured for the miter slot groove and have an extra cut from the end about 1/8" deep and 3/4" long on one end of the table but all in all it is coming out pretty nice.

I now have to router out the recess for the router plate that arrived yesterday. I just did not have enough scrap pieces to make a good level template around the plate so I have to either pick some up at the store or cut down some of the MDF scrap I have to suit the purpose. I do not trust the longer pieces of MDF to remain straight though as I have seen some bowing in the middle. I have to buy a good long straight edge.


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## anotherBob (Oct 28, 2009)

Just wanted to throw another option out there... have recently built a small torsion box table using Phenolic Faced MultiPly: woodcraft.com/Product/2003958/9104/Phenolic-Faced-MultiPly--34-x-24-x-48.aspx

This stuff is really great to work with, resists warping, and doesn't look too bad.


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## Dr.Zook (Sep 10, 2004)

Welcome to the RouterForums Dodo.


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## anotherBob (Oct 28, 2009)

dodo said:


> hello , I'm also new in this forum , and I'm also bulding my first router table.
> Form my expirience , It's almost impossibile to glue two pices of 3/4 MDF or HDF or other material with help of the "home tools " and get realy flat surface
> ( I tried to make the fance that way - big mistake)
> 
> I* strongly recomend to use 30-40mm (1and1/2") beech plywood as the material for the table*If you can afford you can buy Phenolic resin plate , then you can reduce the thickness of tha table plate to 15-20 mm (3/4") , but it's realy expensive stuff


Looks like I can't post link here yet... google for "woodcraft+Phenolic Faced Plywood"

This is some really nice stable stuff to work with. I recently made a small table with this stuff using the torsion box idea & formica on the top surface. The table is kinda small, but dead flat from corner to corner... flat is good.


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## Cassandra (Mar 15, 2006)

Phenolic Faced Plywood - Woodcraft.com


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## anotherBob (Oct 28, 2009)

Ahh, thanks Cassandra... that's the one.


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## AxlMyk (Jun 13, 2006)

dodo said:


> It's almost impossibile to glue two pices of 3/4 MDF or HDF or other material with help of the "home tools " and get realy flat surface


Actually, you can.
Many times you can look at the MDF and see that there is a cupping to it. The idea here is to glue the CONVEX )( faces together. That will cancel out any cupping in both pieces and leave a dead flat surface.

Welcome to the forum.


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## Cassandra (Mar 15, 2006)

*Hi dodo:*

The important things to remember are:

1. When clamping the MDF together at glue-up time, make sure that the reference surface is flat and will stay flat, regardless what the MDF might want to do. That is, prevent the MDF sheets from cupping during glue-up.

2. Per Mile's excellent suggestion, if the MDF is already cupped, put the CONVEX faces together. And then go to rule 1.

I glued two pieces of 24x48x3/4 inch MDF and got a flat 1-1/2 inch top. It was easy since rules 1 and 2 were followed.

*anotherBob:* You're welcome.

Cassandra


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## Kenman101 (May 24, 2009)

I am a big fan of MDF, you can get it at any home improvement store, gluing two 3/4" pieces together makes for a super sturdy core. I let it dry overnight and then laminate the top. After that I cut out the insert. Pretty simple and not very expensive.


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