Router Table Extension Build-Advice Needed.

[Andy Maldoror]

i'm about to begin making a router table extension for my table saw and looking for some advice.

will two sandwiched pieces of 3/4 mdf make for a more solid top or just more weight that could lead to sagging? does it all just depend on the bracing underneath?

i've seen mentioned that it's necessary to put formica on the underside of the mdf if you put it on the top. is this true? i've seen 4-5 shop-built router tables in professional shops with formica tops that don't have it underneath.

lastly, i have been planing on installing the router towards the outside of the table and mounting the 17" incra fence towards the inside. will it be tedious removing the fence every time i need to use the tablesaw and should i consider mounting the fence towards the outside and the router towards the center. this would make for a slightly longer table and would take away the convenience of standing on the end. any thoughts on this?

appreciate any help,
andy

[Ben Hatcher]

My top is an old countertop. I don't have any deflection in my setup because I built an enclosure that goes all the way to the mobile base that the saw sits on. If you have a heavy router you may want to consider making the top a torsion box. If you're really worried about the table length, you could always locate the router in the left side wing instead of the right side wing.

[ron ogle]

I made my table with a frame out of red oak and 3/4 plywood for a top covered with formica on one side. I routed parallel slots on my table and fasten the fence with tee-slots so I can remove easily. Also found that you need a metal plate or you will get sag in the middle over time. Hope this might help a little. Ron

[Myk Rian]

will two sandwiched pieces of 3/4 mdf make for a more solid top or just more weight that could lead to sagging? does it all just depend on the bracing underneath?

It will make a much more solid top.

i've seen mentioned that it's necessary to put formica on the underside of the mdf if you put it on the top. is this true?

Moisture creates warping. It is always SUGGESTED to laminate both sides. Take your pick.
I just use furniture paste wax.

lastly, i have been planing on installing the router towards the outside of the table and mounting the 17" incra fence towards the inside.

You need to have enough room on the outside to support the work piece. Don't cut yourself short there.

[Andy Maldoror]

anyone know of any plans on the internet?

what i've got sketched up now is an oak or maple frame..so no exposed mdf edges. 2 pieces of mdf for the table. formica top and bottom sealed.

i've seen the torsion box and the type where the mdf is attached to the top of a frame...but have not seen the undersides of any where the mdf is framed.
do you build a shelf that attaches to the under side of the rails and lay the assembly on top of that.
if i use 2 pieces of 3/4" mdf that leaves me 1 3/4" to the bottom of the rails. i could use a 3/4" strip of plywood as a spacer, with another 3/4" strip below that extends out as a shelf for the table. this would give me about 2 1/2" for bracing. is that enough support?
using a PC-7518 router and woodpecker lift.
i'll try to add pictures later

[Myk Rian]

anyone know of any plans on the internet?

Plans? Are you not a wood worker?
Make a flat table the size you need, and put a frame around it.
Mount the router, and bolt the thing to the table saw.

[Jerome Hanby]

If I were making the table out of two layers of MDF, I would use the same method as the Mr Sawdust RAS table and use metal splines. I bet you could get away with Shellacking the rest of the table with your laminate on the top. Shellac does a good job of sealing MDF and heading off the outgassing too.

[Myk Rian]

Like this.

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[Carl Beckett]

My router table is two layers of MDF, with shellac on the top surface only. The same for my outfeed table on my tablesaw (hey, I got a truckload of free MDF so used it!). I have found the shellac to be pretty good - its been a few years and no visible wear at all on the router table, and only a little at the back edge of the outfeed table.

When it first goes on the shellac soaks into the MDF a little. Then I built up a couple more coats on top of this.

Im not suggesting its more durable than formica, just saying it seals wel and provides a very durable surface on its own.

[Cyrus Brewster 7]

Your router setup will be very heavy. The more rigid you can make it the better. With this in mind a torsion box may be the best idea.

If you decide to go the double MDF route (which will soak up vibrations better), some heavy gauge aluminum 'L' stock or VERY straight angle iron in front and behind the opening should eliminate future sagging. Place these so they are located under the front and back lip of the router lift. The length should be almost the entire width of the table (parallel to the mite slot) and attached with at least 5 screws. No need to attache to your table saw rails.

Poly and wax will also work well to seal the surface.

[Adam Cook WV]

I recently got a real tablesaw and I'm working on the exact same project. I think that the plan in Fine Woodworking (Tools an Shop winter 2010/2011 annual issue pg. 50) is the best I've seen. I'm about halfway through building mine. I used a laminate topped side extension table that came with my used unisaw instead of mdf the plan called for, mostly because it was there and free. I used some left over pieces of red oak for the torsion box, but the plan calls for baltic birch plywood, looked like it would work fine and probably easier. once again, the oak was there and already paid for. The thing I liked most about the plan was the built in dust collection and an excellent fence design. I haven't built the fence yet but I'm going to use mag jig magnets insead of the irwin clamps showed in the article. I, haven't posted any pictures on here yet but if your interested I could try monday evening. I was going to buy a kreg or bench dog router table until I saw this plan, now with the money saved I might get a 3hp triton router and still be to the good. Take a look at the fence, definitely not an incra, but very simple, looks effective, and is good enough for the former shop manager of FWW, I figure should be good enough for me. I like simple things that work. This might save you some money too.

[keith micinski]

I built this and am getting ready for design 2.0. http://www.sawmillcreek.org/showthre...ion&highlight= I am going to take a piece of granite that I have laying around and see if I can't get someone to cut out the router plate whole. Then I am going to cut the end of the router extension off and stick it on there. I used a torsion box and I am still getting a little bit of deflexion across the width of the router opening.

[Andy Maldoror]

just thinking about it...would running angle iron parallel to the mitre slots still allow it to sag laterally? if i just mount it on to the saw table with legs on the other end. or do the irons just do enough to hold the sheets rigid atop the frame.
also how would you fit the L stock? miter cuts with tablesaw?

[Norman Hitt]

Fasten one flat side of the L stock, or angle iron to the bottom with screws (or what I like better is small bolts through the metal and up through the bottom laminate and pre bored MDF into "T" nuts that were countersunk and set flush into the prebored holes from the top side "BEFORE" the Formica laminate was put on the top side so the T nuts will not show). One side of the L stock will hang down (vertically) giving maximum support from sagging and no loss of strength of the table since it has no groove in it for the L stock. I cover both the top and bottom of my laminated MDF tables with Formica after wrapping the MDF with 3/4" oak. When I put the Formica on, I cover both the MDF and the oak wrapping on the top and bottom and this completely seals the MDF from moisture. On Router table tops That are not in a TS extension, ie; Stand alone Router Table, I chamfer all four edges (top and bottom) with a chamfering bit set to remove about 3/16" from the edge (or whatever distance looks appealing).

Order of build:

1. Laminate two pieces of 3/4" MDF (Using cauls to keep it flat all the way across, both
directions). You can also use screws scattered around that can be removed after
the glue is dry, BUT, if you do this you need to pre drill those holes AND, counter-
sink the holes on BOTH inside faces, or the area around the screws will bulge
as you drive the screws in and hold the two layers apart.
2. Square up Laminated MDF and trim it to size (minus the two thicknesses of edge
trim in each direction).
3. Glue 3/4" oak trim/wrapping to all 4 edges of the MDF lamination
4. Check for square after the glue dries on the oak trim & re square if necessary
5. Laminate the "Bottom Surface" with Formica
6. Drill and countersink holes for the L stock from top side (only deep enough to install T nuts slightly below the surface), then drill a smaller hole for the bolt to go through the rest of the lamination and
bottom Formica laminate, and install the T nuts, placing a small tab of masking tape over the T nut hole to keep the laminate cement out in the next step.
7. Laminate the top surface with Formica, and use a Laminate trimming bit in a router to trim the laminate on all edges, both top and bottom
8. Install the L stock, (using premeasured length bolts fitted to properly tighten up in the T nuts "WITHOUT" touching the top laminate!!!!!!!!!
9. Place the table on roller stands (OR other means of support) between the TS extension rails and shim level with the TS. Place long clamps across the table to tighten the extension rails against the table and hold it in place as you fasten it to the TS. Recheck to see that the table is still level with the TS and then drill and countersink holes for #10 Screws through the extension rail angle iron and drive screws through them into the oak wrapping.
10. Use the TS Mitre Slot to align the Router Cut out Template and then cut the hole and mount the Router.

"IF" you build in this order, you should not have any OH $^@% !!! moments.

Hope this helps.

[ken gibbs]

Just a thought to keep you from fainting when you see the price of the countertop grade laminate. I have a local cabinet shop that keeps and sells laminate scraps. The good stuff sells for around $50 to $80 for a 4' X 8" sheet at Lowes or HD. You can save a lot of cash by using scrap partial sheets.