First for the slot spacing: If you want the slots to be 16" long, I'd take an 18" long piece of MDF, say 3/4" thick and 12" wide and cut 16" slots in it (spaced as far apart as you wish the 1/4" grooves to be placed) with a 1/2" bit.

Second for the taper: If you take that 18" long piece of MDF and glue a 3/8"x3/8" strip along one (12") end, the top has a ~1/4" in 12" taper when placed strip-down.

Third for the cut: If you put a 1/2" OD guide in your router base before the 1/4" bit., the slot you cut earlier will make a perfect guide for the bushing to rest against. Now you'll need to do some test-cuts on bit depth with some scrap before cutting the Corian.

You'll need to modify this to fit the size and shape of your sink.

 

Hi - Welcome to the forum
Glad to see Jim came in, I had to sleep on this one. I had in mind a similar jig but was wrestling with two issues that I see. One is securing it firmly, especially if everything (counter, sink, etc) is already installed. I think that is one of those situations where "ya gotta be there" because there are so many variables. The second is the rigidity, I would suggest you make the thing out of 3/4" stock to make sure there is absolutely no flex. The jig would also need to be absolutely smooth. Actually, if you have some scrap Corian, it would make excellant jig material.
Another suggestion, and this is strictly from an aesthetics standpoint, I would think wider and shallower would be less noticeable. Say 3/4" to 1" wide and no deeper than 1/16". A bowel bit, like the one pictured, would give such a profile. If it has a top bearing you would not need a bushing nor would there be any offset to compute.
Just a couple of suggestions - Good luck

 

Hi

I would suggest the way below..use your taper jig to cut the strips on the table saw..than stick them to the counter top..using DST..

MLCS core box and round nose router bits

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All great ideas, thanks! I agree, the wider grooves will look nicer. As for securing the fixture, it's common during seaming operations to hot glue temporary clamping blocks to Corian and knock them off (and sand) afterwords. My table saw is a tired old benchtop, so I'm not sure if I'll attempt to taper per bobj or shim per BigJimAK.

 

Precision Taper Jig - Rockler Woodworking Tools

Works on all table saws ( tired old benchtop as well )
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Do you have a picture of project completed? would like to see finished result. thinking of doing same thing

Larry

 

what does DST stand for?

 

Hi

DST=Double Sided Tape also call carpet tape..

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Hi

The Money Pit: Routing a Kitchen Draining Board

Draining Groove Jig - Trend

Mistral Solid Surface Worktop - Drainer Grooves by Karonia - YouTube

Routing Wooden Worktop Drainage Grooves (HD) - YouTube

 

So after mulling it over a bit, I decided what to do and finished the grooves this past weekend.

I really liked the design of the Trend/Unika Euro-style templates, so I made one by laying up 1/2" thick strips of MDF onto a piece of 1/4" MDF. I ran a 3/4" bowl bit with an upper pilot bearing along the channels, routing through the 1/4 MDF, to finish it off. This additive assembly approach allowed for true, parallel, evenly spaced channels in my template. (Come to think of it, this approach would also make it possible for a fancy pattern of converging grooves or some freeform branching pattern.)

To get my pitch, I cut a handful of thin wedges about 12" long and 1/4" at the thick end with a Rockler taper jig and secured them to the underside of the template. I went with something a little less than 1/4 a in 12". It's hard to say exactly what the pitch is because at that shallow an angle, deviations tend stack up pretty quickly.

I secured the jig and wedges to the Corian countertop with a several small pieces of 3M "Extreme" mounting tape supplemented with some of their conventional indoor double sided tape. For extra insurance, I placed a couple bearing blocks against the walls and backsplash. There is such a thing as overdoing the DST, and I pretty much ruined the template removing it after making my cuts.

The 3/4" bowl bit I used had 1/4" radii at the edges, so with 2 passes, I cut a nice looking, 1" wide groove, while bearing on a guide strip on each pass.

There was a little flex to the template before I put the wedges on, so if I was to do it again, I might lay 1/2" strips on a thicker, 1/2" flat. Hopefully, the the bit would still be long enough to protrude through resulting 1" thick template and still have a useful depth of cut. Also, I think I'd make the template longer and wider to allow areas for clamps that wouldn't interfere with the router base.

 

So after mulling it over a bit, I decided what to do and finished the grooves this past weekend.

@klarc - I'm glad you got the grooves finished this weekend, but I have to ask, "are you sure you didn't rush into this?" I mean, your original post was in March, 2010 :grin::laugh2:0

 

Your results look good.

 

I believe I took an appropriate amount of time for thought and planning. My opinion is not widely shared in the klarc household.

 

Ha - if your household is like mine, you can be sure you'll be told if you do something wrong >