Help me make this rabbet cut in the top edge of a cabinet wall

Question

I need to route out an edge in a cabinetry side to allow a top mounted handle to recess when door of the adjacent cabinet opens.

I have a portable router that accepts 1/4” shank bits and I am trying to find a suitable bit to do this cut. Removing the panel is not an option. What you see on the photo is two 3/4” plywood boards stacked together, and I pretty much want to notch out all the way in of the outer board.

I can find 1/4” shank bits with changeable bearing sizes that can cut variety of width up/to 1/2, but their cutting length is just 1/4”.

I am pretty handy with woodworking tools but haven’t done wide variety of routing to know this. Is it possible to do multiple passes with a bit like this, each time going deeper into the frame to achieve the final 3/4” length? Thanks.

Answer 1

You absolutely want to make this with a number of small passes! While your little battery powered router is a great tool (and on my shopping list), it is not a production quality tool designed to route out a 1/2 x 3/4" rabbet in one pass.

I would strongly recommend using Criggie's suggestions for temporarily making a wider base for your router to sit on while you're doing this, both for the accuracy of your cut and for the safety of your fingers.

I would suggest a small straight cutting bit that can reach down the 1/2" depth of your cut. Make your first pass at about 1/8" depth, and rout out the entire area, then reset the bit to 1/4" deep and make another pass. Continue making passes about 1/8" deeper each time until you've reached your final depth. Doing this will yield a flat bottom rabbet with a fairly sharp 90° corner at the bottom - you will have rounded vertical "corners", and can clean these up with a sharp chisel (also recommended by Criggie) if you need them to be nice and square.

If this cabinet is not yet attached to anything, you might consider tipping it on its side (lay it on a piece of cardboard if the other side is finished and to be exposed) and getting a bit that will cut to a depth of 3/4". You can use the wide flat side of the cabinet (currently vertical, along the plane of the 1/2" dimension) as a much more stable base for the router, and probably won't have to add on any scrap to provide an additional platform. You'll need to make more passes (I'd still recommend only 1/8" deep at a time) to get to the final 3/4" depth, but you'll get there in the end.

Attempting to hog this all out in one single pass will be very hard on your small router, will likely end up in a lot of burning of the wood, will not give you a very nice cut, and could cause the thin 1/4" shaft of your router to snap, hurling a small, hot, very sharp projectile at high speed in a random direction across your room. Most people consider that a Bad Thing™. Making that cut in one pass really is only in the purview of heavy duty, industrial strength, production shop level of shaping machines that are set up to make 1000s of cuts like this each shift.

Finally, if you have more woodworking type questions, I'd encourage you to check out Woodworking.SE (oddly, dedicated to woodworking! ;)

Answer 2

I'd start by making the job easier - Give your router a wider flat surface to slide on, not just the top of the cabinet sides. Screw two sacrificial pieces of scrap on either side such the screw holes won't be seen.

Perhaps lay a thin flat piece of smooth scrap on top, with a slot in that top piece so your cutter can reach the work.

Lastly, screw or clamp two or more guides on the sides of your top-scrap piece, to act as a fence for the router.

You can cut some amount per pass, and extend the bit then repeat. Slow and steady does this better.

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If space doesn't allow that, you could essentially do the same from the side, but then you're fighting gravity too. Best to use it instead.

As for a cutter, perhaps something more like an endmill would work here. There is risk of chipping the laminate surface though so you may choose to pre-cut it on the line with a series of strokes of a sharp knife.

Don't be afraid to use a sharp chisel to finish the ends - no round cutter will get in there perfectly.