# How do you get more exact dado cuts?



## davenewbie (Feb 8, 2005)

Often times I do a dado cut with the router and find circumstances where due to expansion of the wood or whatnot the cut is under the width of the wood often times about 1/16 of an inch under. 
I could pound the wood into the joint, but you can obviously damage the piece in doing that, or running another pass with the router to get that width is tricky since you could easily create a dado that is too wide. 

Any suggestions on that?

Thanks...


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## BobandRick (Aug 4, 2004)

davenewbie said:


> Often times I do a dado cut with the router and find circumstances where due to expansion of the wood or whatnot the cut is under the width of the wood often times about 1/16 of an inch under.
> I could pound the wood into the joint, but you can obviously damage the piece in doing that, or running another pass with the router to get that width is tricky since you could easily create a dado that is too wide.
> 
> Any suggestions on that?
> ...


Davenewbie we talked about a method to making oversized dados in a router tip a while back. Check out this tip


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## Dewy (Sep 15, 2004)

When I cut a trench (dado) I often need it wider than the cutters I have.
I use some very thin plastic card of a known width between my router base and the straight edge or some thicker plastic strips if I know I will need to make the trench much wider.
After making the first pass, I remove one or more strips of plastic for subsequent passes until I have the width required.
By doing it this way instead of making the first pass without these spacers I avoid climb cutting on the other passes.
You could use a 6 sided offset trenching router base where each side is a given distance from the router centre but the ones available here in UK are 1mm different per side which never matches the amount I want to widen the trench.
You can, of course make your own base out of acrylic template material.
Such templates are worth their weight in gold.


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## Woodnut65 (Oct 11, 2004)

Hi: Newbie:
I use a Micro Fence, this goes on the router like a standard guide fence, but it has
a micrometer built into it, you measure the material that must go into the dato with
a cliper, measured in thousanths. Make a first cut with a smaller bit meaures the 
dato, then add the difference by adjusting the Micrometer fence, plus a few thousanths to allow a good fit.

Hope this helps.. Woodnut65


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## Mike (Nov 22, 2004)

There is the possibility that you have a plywood bit which is marked for the size of plywood it is intended to be used with but is actually undersized, or you could simply have a bit that has been sharpened and is now undersized. Always measure the wood and the bit to be sure. Either way a slight adjustment to your fence and a second pass and you will be good to go.


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