best way to cut 3/4 inch slots aross oak plywood


Old 03-05-05, 12:23 AM
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best way to cut 3/4 inch slots aross oak plywood

Im redoing a built in shelving cabinet. i'm applying 1/4 inch oak plywood to the face and sides and 3/4 inch plywood at base . i want to groove the base to fit my 3/4 inch shelving braces(supports). what is the best way to do tthis or are there better ideas. I dont see how i can cut the grooves accurately with a free hand router and table router wont fit. I want a tight fit.
Old 03-05-05, 06:33 AM
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No free hand

When I want a very straight cut of a plywood sheet with a circular saw, I use a saw guide - a two-piece aluminum channel that clamps to the plywood, allowing the shoe of the saw to ride one edge of the guide. It's two pieces to make it easier to store.

For your purposes, a new piece of angle iron (so no warpage due to loading) could serve the same purpose. It must be positioned off the groove by the radius of the router base.
Old 03-05-05, 08:40 AM
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Sneaky, here are a few ideas. Please keep in mind that 3/4" plywood is not 3/4". It's all in millimeters. So it ends up being about 1/32 or less, less than 3/4" You don't want your plywood to be so tight that you need to force it in with a clamp, or you'll end up with problems because of expansion and contraction.

Use two saw horses, clamp your board down to each of them. Take a piece of plywood with a nice smooth edge on it and no imperfections along the edge as in voids, because your router will follow those.

Measure from the outside of your router base to the inside edge of your bit. So measure from the left to the inside of the router bit. This will tell you where the piece of plywood needs to be positioned.

I ()

The I represents the edge of your 3/4" plywood scrap that you'll be using for your router to ride on. The () represents the router bit. The ( sign is the left side of the bit.

Use a square "L" square and mark the line's where you need to put the dados. Take the dimension you get from the outside of your base to the routerbit and that will be your bible for all of your cuts.

Now, measure from the line of your dado outward to the left, and that will be where you'll clamp your piece. Flip on the switch and route.

I wouldn't take off more than 1/4" The key is not to move the bit up or down or to even go back to the same dado with a deeper cut, because you'll never get it lined up the same again.

Keep in mind, you MUST keep constant pressure against your guide, because if you allow your router to slip, it will ruin your piece. You can always clamp another piece on the opposite side of your router "The distance apart that is the size of your router base, for extra security.

Old 03-05-05, 02:58 PM
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If it was me, I'd use my dado blade and table saw. I have a 24 tooth adjustable dado blade and dado insert for my table saw. It's nice to be able to adjust the wobble so that the plywood just fits nice without being too loose, or having to force it into place. Works great for making dados!
Old 03-07-05, 06:42 AM
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ajustable dado that wobble does not make a square cut.
Stack dado does.
As for thicknees plywood are made in Canada and there all metric.
so 3/4 in plywood is 19 mm.


Old 03-07-05, 07:32 AM
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I'm not sure if I see any mention of having a table saw. I believe a router and router table were the only items mentioned.

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