Router table top

[Dick Holt]

I want to make a router table top. Most plans for router tables show the tops as one or two layers of MDF. A few show plywood. Plywood is not usually dead flat like MDF. MDF is flat, but doesn't hold screws well. I was wondering if a combination of the two would be good. I am thinking of using plywood for the bottom and MDF for the top. The bottom plywood would hold screws well and the top would be dead flat. What do you guys think? If the top is covered with plastic laminate, should the bottom also? What kind of glue would you use, yellow or contact cement? Thanks for your help.

Dick

[Anthony Whitesell]

I used two layers of particle board (my straight edge said it was flat) with a 1/2 plywood bottom and a laminate top. It's probably 3-4 years old and still flat. I don't think I would use a thick plywood for the bottom, for the fear it may warp and if it does it may have enough strength to warp the whole top. I don't think 1/2 plywood has enough strength to warp 1 1/2 of particle board. I used contact cement all around. I found it less likely to puddle and what puddles there were are not as tall as those formed by a yellow glue.

[Victor Robinson]

I used two layers of MDF (glued with yellow glue) and plastic laminate on both sides (contact cement). It has only been a year, but the thing is dead flat.

What ate you wanting to screw into the top? There may be other types of fasteners you could use. For example, I used threaded inserts in the top and bolts to float the top above my cabinet on some foam.

[glenn bradley]

MDF, while flat is malleable. If your ply is uneven and you laminate the MDF to it under pressure, the MDF will be more likely to adapt to the plywood's landscape than vice-versa. MDF holds screws fine in this scenario. Its not like you will be lifting a router table cabinet by the top held only with screws ;-) I have an MDF top that has been in place for years. The previous MDF top is still fine and serving another purpose elsewhere. You'll have 1-1/2" of MDF to screw into from below. Use screws or counterbore to allow 1-1/4" of screw to go into the MDF. Drill a pilot hole that goes 1-3/8" into the MDF just a bit longer than the screw) and is sized so that only the threads cut into the material. This provides a good grip, no danger of split or malforming. Pretty much the standard method of using screws in MDF. Similar to the method to properly seat lag screws (as opposed to just slamming them in with an impact driver) ;-) Your real concern should be the supporting ribs under the top. Give yourself lots of support to avoid eventual sagging.

Granted this info is from folks who have a vested interest (http://www.norbord.com/images/screws-MDF.pdf) in making us like MDF . . .

"The use of pilot holes is strongly recommended forMDF applications requiring screws. Pilot holes are
required when drilling into the edge. Pilot holes should
be between 85% to 90% of the root-diameter of the
selected screw and drilled to a depth equal to or slightly
more than the screw’s driven length, especially on the
edges."

[Andrew Pitonyak]

I used 1" MDF and I did not laminate two sections together.

I used a laminate for the top and bottom (chose the cheapest at lowes so I have a bunch left.... if only you lived closer).

I built a lattice out of oak to support the bottom to prevent sag.

I built a frame out of oak and I routed lip and then I dropped the MDF top into it. I set the depth so that the edge is exactly flush with the MDF.

I wanted to screw into the MDF so I

Drilled a hole into the MDF.
Tapped the hole for a screw.
Drizzled in some CA glue to solidify the MDF.
Re-tapped the hole in case glue was where it should not be.
This worked very well. I also did some tests using some coarse thread screws (think pocket hole screws) and those seemed to held very well. Regardless, I recommend that you perform a few tests so that you understand how much abuse your MDF will take.

[Larry Frank]

One way of making screws hold better in MDF is to drill the hole and then put super glue into the hole. It will soak into the MDF and make it much harder and stronger.

[David Micalizzi]

I have to try the super glue idea that sounds interesting...:rolleyes:

[Andrew Pitonyak]

I have to try the super glue idea that sounds interesting...:rolleyes:
Try it on scrap..... Try all your fastening on scrap first. I blew out a few pieces on scrap before I had set my drill that I was using to drive screws so that it would not cause a problem. And yes, love that whole glue thing to make it stronger.

[pat warner]

"What do you guys think?"
********************************
Let the frame support the top (http://patwarner.com/images/selecting4.jpg).
Get all the sticks in the same plane and screw the top down on to them.
It will not move, it will not cup. I'm using a 5/8" thick slab of Medite brand MDF.
Has lasted >10 years without formica. Loaded with antique oil and wax, however.
Castings of either a 7518 or 5625 can be directly screwed to the fiberboard, no inserts.
Why complicate things?
******************************

[Kevin McCluney]

For the first router table I built many years ago I used two layers of particle board glued together, edge-banded with 3/4" oak, with laminate on top (contact cement), and painted on the bottom. It eventually warped over a period of years. Even though heavily painted on the underside, it was insufficient to prevent the moisture from reaching the MDF. For my current table the construction was similar - I used two layers of 3/4" MDF glued together with yellow wood glue, banded with 3/4" maple (including the hole for the router), and with laminate on both sides. I also inset maple where I later installed the aluminum tracks for the fence and the miter slot (I'd leave the miter slot out if I had it to do again) - see the first pic below. The second pic shows the top after the laminate was applied and with the miter track in place; T-slot tracks went in the other two slots. The maple eliminates any worries about the screws not holding. The new table's been in use 7 years with no warping so far.

224321224322

[glenn bradley]

and with laminate on both sides.

Good reminder for those who often ask "do I have to do both sides?". Answer; only if you want your efforts to last. Thanks Kevin.

[David Micalizzi]

Try it on scrap..... Try all your fastening on scrap first. I blew out a few pieces on scrap before I had set my drill that I was using to drive screws so that it would not cause a problem. And yes, love that whole glue thing to make it stronger.

Thanks for the tip Andrew! I like using MDF because of the cost, and how flat it is. Hate the dust it produces and the fact it doesn't hold screws well. The glue trick though it takes more time helps deal with one of the draw backs.

[Don Morris]

Minimun 2 layers of 3/4" (1" better) MDF glued. Laminate both sides, worked well for years. In the Kreg DVD on building your own router table, they say to buy a top because there are too many good ones out there cheap enough, so that making your own is not terribly cost effective.

[Greg Hines, MD]

Screws into MDF: One technique I have seen was to use your Domino to cut slots and then glue in the Dominoes, and then put your screws into the hardwood of the Domino. I don't have a Domino, but I have used large dowels in one project for the same reason.

[Jim Andrew]

The last router table top I built, I used some ash 1" lumber that had been sitting in my wood rack for some time. Just one layer, put poly on both sides. And it is staying good. Don't think I would have had great results if had just purchased the lumber and built it right away, but the wood was used to my shop already.