# How flat should a router table be?



## AVman (Apr 23, 2008)

The question is, how flat should a router table be? Since I have limited space in my garage and I needed a work table and a router table so I opted to combine them. I started by building a 2 by 6 frame with 4 by 4 legs and bracing every third of the way down. The table size is 3 by 6 foot. I am planning to mount the router on the end of the table. The top is made of two 3/4" sheets of birch laminated together with a 3/4" mdf melamine top. What I have encountered is a cupping in the top depthwise about .02 worth. I am thinking that I can shim between the frame and the top with body shims and attach the top with lag bolts every 9 inches or so. Does anybody have any suggestions or thoughts on this? I come for the machining world and .02 is a lot or is this acceptable? Thanks.


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## Bob N (Oct 12, 2004)

.02 would be VERY acceptable for a router table top and should not give you any problems.


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## bobj3 (Jan 17, 2006)

Hi AVman

So many go a bit over board about the table top being flat, it's not a real big deal, because so many other things come in to play,,,most just rip the stock on the table saw some run it over the joinery/planer but most don't 

You are making something out of a tree that's still alive so to speak, if you thing that it's dead cut a real thin piece and watch it bend when you cut it off the tree board...it was a tree and want's to be a tree again.. 

No other material will act like wood, put some water on it and watch it become a tree again...  the grain will raise up and the board will bow and bend ,,,,so to say many things come into play, you are not making a rocket...just something out of a tree.. 

Here's one more test that's fun to do , make some molding on your router table, rip the stock to 3" wide chuck up a round over bit and put a nice edge on the edge of the board now rip off the molding piece , then take a hard look at it, it will be bent and you know it was true when you started out...  the longer the part the more the bend/bow, once a tree always a tree.. 

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AVman said:


> The question is, how flat should a router table be? Since I have limited space in my garage and I needed a work table and a router table so I opted to combine them. I started by building a 2 by 6 frame with 4 by 4 legs and bracing every third of the way down. The table size is 3 by 6 foot. I am planning to mount the router on the end of the table. The top is made of two 3/4" sheets of birch laminated together with a 3/4" mdf melamine top. What I have encountered is a cupping in the top depthwise about .02 worth. I am thinking that I can shim between the frame and the top with body shims and attach the top with lag bolts every 9 inches or so. Does anybody have any suggestions or thoughts on this? I come for the machining world and .02 is a lot or is this acceptable? Thanks.


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## dovetail_65 (Jan 22, 2008)

In short I think Bob is saying the wood moves more than .02 and will never stay within that tolerance anyway. That's why we design cabinets and tables with wood movement in mind.


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## AVman (Apr 23, 2008)

*Thanks*

Guys,
Thank you for your input. Like I said I am new to wood working and I am still getting use to what is acceptable.


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## Hamlin (Dec 25, 2005)

Hi,

IMHO, it's the plate that has to be flat and slightly higher than the table. The cut is being done at the bit so, once you've passed the bit, the cut is done. I hope that doesn't sound too confusing.


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## dgave (Aug 24, 2010)

The problem with a significant sag (in my admitedly limited experience) is that it becomes almost impossible to level the insert plate. The last thing you want is your material catching on the lip of the insert on the in-feed or the lip of the table on the out-feed.

I'd say that any amount of sag that prevents you from getting the insert plate level with, or slightly higher than, the table top on all four sides is too much. I had that very problem with the table I bought and wound up getting the manufacturer to replace it.


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## ccmnova (Nov 4, 2009)

My first table was cupped as well but worse than .02 - it was a plastic material. The cupping was in certain areas and sometimes caused problems. I used my belt sander and worked on it for hours until it was very flat. I don't know that .02 would be a problem, would depened on where it was, but a flat table is always good to start with !!


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## BowlBit (Nov 2, 2009)

I have to agree with BobJ3.


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