How to shim Router Table...

[Andy Sowers]

Hi

I'm in the process of building a router cabinet/table in the familiar style of Norm Abram's design. I'm now nearing the final stages of attaching the actual router table top (in this case from Woodpeckers) to the cabinet.

I chose to use a 3/4" MDF "subtop" for lack of a better word so that the actual router table would be well supported across the entire bottom. The MDF subtop is darn near dead flat, if anything its a small bit center-high. The converse is true for the Woodpecker's table. Its clearly sagging in the middle even without the router installed. I don't have feeler gauges so I can't say how much but you can clearly see daylight if you shine a light from behind a Lee valley straight edge.

The instruction sheet that came with the tabletop spells out a procedure to flatten the top with shims. They advocating using business card stock as the shim material. Is this what is generally used? Seems to me that the paper could break down over time...

Originally, I thought about countersinking a series of small screws across the top of the MDF subtop that could be raised up proud of the surface to provide an "adjustable" shim. however, I've pretty much dismissed that idea because I'd worry that over time vibrations might cause the screws to wear away the bottom of the table eventually causing the top to sag again...

Any suggestions? I've attached a few pics of the cabinet with the subtop, and with the router table top placed on that (not yet secured) and a picture of the "daylight" under a straightedge... note, that this picture makes it look much worse than it really is... probably due to a poor camera focus and a somewhat shiny top...

Thanks

Andy

[Bill Huber]

I use aluminum foil when I shimmed mine.

I cut strips 3/4 inches wide and just folded it over until I had the right thickness. then put in under the table.
My problem was not the table it was the cabinet, I did not get it made as flat as it should have been.

[Cliff Rohrabacher]

I hung mine off the rear of my slider so I could use the slider on it too.

I got my table and insert "just so" by:
1.) Applying an epoxy and sawdust paste to the place where the table top was to be seated
2.) setting the top in place
3.) laying a couple dead straight timbers I jointed for this across the iron saw top and clamping 'em down to the saw top
4.) and clamping the router top to the timbers such that the top was bring lifted up to the timbers and prevented from settling into the epoxy paste

Same deal with the Roussou insert.

I bet that epoxy and upward clamping trick would work to get your insert dead on if your table is already in good shape.

[john bateman]

If their table is sagging in the middle, you may not need to shim anything. Run some lag bolts with washers, up through your "sub-table" near the ends of the cabinet. This would pull the outside edges of their table down flat.

If their table is sturdier than your subtable, you may end up with everything warped, however.

[Joe Scharle]

I used blue tape