router and dados

G'day Mark, I'm assuming that your router has a round base?? Try this, clamp a straight edge onto a piece of timber, Rout into it and then rotate the router keeping the base against the straight edge. Unless your base is EXACTLY central and perfectly round, you will notice that the bit cuts closer when a certain point of the base is against the edge and further away when another point is against the edge. Quite often all that is required is to make one run with the base in one position and another with it in the opposite. If this is not enough to give you the clearance you require you can always sand or file a smidge of one side of the base. Hope this helps.

Hope you can understand it :)

regards John

Make an eccentric rectangular base for the router. That is, each side is a given distance from a chosen bit. One side may be 3 inches away, the next may be 3 and 1/8th, and so on, in increments of your choice. Obviously, mark the base with the measurments and it's orientation with the router, and the specific bit used. Tom

Ping Leon and find out where to find the plans for his homemade adjustable router jig that will allow you to cut the dadoes to the precise thickness of your melamine.

There are other jigs that will do the same thing, so you might DAGS on the newsgroup.

The mark entity posted thusly:

Well, plywood varies in thickness, and though I don't know how close the tolerances on Melamine is, there is hope.

Best is to not rely on the size of the bit, but to make a jig that eliminates the problem regardless of the size of the bit and the thickness of the wood.

Several solutions have been posted here, but the basic idea is make a jig in which one guide edge slides such that you vary the width of a slot, and the slot is set to the thickness of the plywood. The bit you use is smaller than the required width of the dado. It was the first jig I made, and it works beautifully.

The one I built was detailed in Woodsmith's "Shop-Built Jigs and Fixtures". If nobody else posts a link, I'll try to take a picture for you.

| My kitchen cabinet building experience has not been a good one so | far. Here is my latest problem. I am building the boxes from 5/8" | melamine and I am doing most dados on the table saw. There are a | few locations were this is not practical and I want to use a router | and guide. Anyway a 5/8" bit is too small I will try a 16mm but I | think it will be too small as well freud does not make a 17mm or a | 21/32 and an 11/16" will be way too big. Is my only option to make | a jig with rails sapaced 1/32" wider than the router base and use | the 5/8" bit too widen the dado? It is rediculous that I can't buy | a router bit which matches common 5/8"melamine.

Mark...

Leon came up with the jig that should do just what you want. With his permission I've posted his photos to a web page; and (without his permission) I added the drawing I made when I built my copy. You can use the link below to get to the web page - you can click on any of the images to get a better view.

-- Morris Dovey DeSoto Solar DeSoto, Iowa USA

Sample in pix:

It's really not necessary, you just have to make 2 passes with a smaller bit. You can either set up your guide fence twice, or make a simple jig for running dados where you run down one side of the fence, then back up the other. I remember seeing a couple of plans for a simple jig in the last couple months, I think in both Shopsmith and Popular Woodworking, but I'm sure you can find one online pretty easily.

There is a picture of one over on abpw in a thread entitled Dado Jig For Router.

Thanks everyone, that jig is so simply yet ingenious. I tried the 16mm and it is a very tight perfect fit but I am sure I will come across melamine a hair thicker that will not fit. I am going to make that jig for sure.

The mark entity posted thusly:

If you are speaking of the one on abpw, it is pretty simple and works well. You can thank Woodsmith for it. :-)

The eccentric rectangular base, supplemented with shop made shims for the second pass allows me to adjust to any width dado that I want. The base is in 1/8" increments. Bugs