Mounting MDF router table

[Rick Huelsbeck]

As many of you know I've been in the market for a router table. I've been pretty much convinced I really don't want a folding table, saw a couple over the weekend and was not impressed. I'm going a different route :D as it were, I've gotten a pinnacle offset table top (MDF), Pinnacle Premium Positioner Fence System (got the incra templates to go with it too), and pinnacle aluminum mounting plate (guess where I was on Sat :D) Ok, I'm going to break down and take the time to build my own work stand for it, it's going to have wheels so I can roll it off to the side when I'm in need of some more room. Anyway what I want to know is how would you mount an MDF top to a 2 x 4 frame? A thought I've had it to glue wood to the underside of the table that will match to the frame to keep it from sliding on it, maybe put some screws from the wood on router table into the frame. I hate the idea screwing into the mdf as it may weaken it, plus it really makes a mess if a screw pulls out of mdf.

[Jim Becker]

Screwing up into the MDF is not going to weaken it and if you use appropriate fasteners, it's going to hold just fine. What's most important is that you provide good support for your MDF table including "inside the lines". You want a framework that will keep the table from sagging over time from the weight of the router and other gear.

[glenn bradley]

Jim is right on this one (as usual). As an 'experienced' MDF top user I have been down the road of "there's no way that will not stay flat". The support frame is critical. Joint the surfaces that will contact the top from underneath. Spend an inordinate amount of time with a builder's level or straight edge and shim material to assure the frame is flat across it's surface. Do not leave any span of 12" or more of your top unsupported by at least some part of the frame.

All that being said, I screwed into my MDF from underneath using coarse thread screws (McFeely's washer head IIRC). Usual MDF screwing rules apply: Drill the pilot hole deeper than the screw will penetrate, size pilot to fit the screw's shaft so that only the teeth cut into the MDF, countersink the hole where it will contact the underside of the table to avoid 'volcano-ing'.

I have had no problems for years and have had the table off and on several times.

[Harley Reasons]

One other thing you can do to strengthen the screw holes is to put a few drops of CA glue in them and let it dry for about 30 seconds. It will provide a lot of additional holding power to your screw holes.

[Rich Engelhardt]

Hello,
I asked the same question about a month ago.
I was advised to use Kreg coarse thread pocket hole screws - which I did.
Worked like a charm.

Shimming is highly recommended.

Also - keep checking level as you drive the screws home - I didn't and have to go back and redo mine. <-- the bad news.

The good news - there's a slight "crown" in the top. If I place a 4' straight edge across the top, I can see a little daylight on both ends.
From what I've gleaned, that's ok.

[glenn bradley]

One other thing you can do to strengthen the screw holes is to put a few drops of CA glue in them and let it dry for about 30 seconds. It will provide a lot of additional holding power to your screw holes.

Harley, I have wondered about this. Can you easily back the screws out for shimming and adjustment after using CA? Does it "glue" the screws in or just soak into the MDF material and create a more solid material? I guess the basic question is what happens when you back the crew out? I guess I could take my own "oh-so-frequent" advice and just try this out on a test piece :D. Funny how we think of these things as we're typing :).

[Myk Rian]

I drill a pilot hole then use a countersink. That way, the MDF won't puff out. I also use sheet metal screws. Works great.

[Alfred Toy]

Build a torsion box to support the top. This fella built the router table project (http://www.whitemountdesign.com/RouterTableProject-1.htm)from April 2005 Popular Woodworking. Compact, brawny accurate and cheap.
Link at the bottom to go to start of project.

"Another decision was to build the router table top as a torsion box with glued and screwed internal supports or webbing, this to eliminate any possibility of table sag. The torsion box will be very rigid and unable to sag due to its inherent I-beam design characteristics."

I would be inclined to build the torsion box with top over hanging the torsion box to match the size of the pinnacle top, then remove t-tracks and drill thru the pinnacle top, add propell nuts counter sunk (t-nuts without the spurs). Replace T-Tracks. Then use threaded knobs to thread from under the torsion top. If you decide to remove top, spin off knobs. The torsion box top eliminates any chance that the Pinnacle will sag, considering the cost of the Pinnacle. The threaded knobs only hold the Pinnacle in place. Rather than taking a chance of screwing in to the Pinnacle with screws that may strip or bulge or pull the Pinnacle so that it bows.