What are my options for cutting notches in the corners of large shelves?

Question

I'm planning on making a shoe rack/bench, and have been trying to figure out the best approach to cutting the corners on these 46" wide shelves:

I've made something similar in the past, and cut out the corners with a jigsaw, but I was not happy with the results. I now have a table saw and handheld router, but can't figure out a way to make these cuts consistently.

I haven't attempted it, but I'm pretty sure that using a dado stack on my table saw is not feasible with something this long.

Another idea I had would be to clamp up the bottom two shelves and use a straight cut router bit with a guide – but consistency might be a challenge?

Is there another approach that would make sense for this?

Answer 1

There are three main approaches here: table saw, router table and by hand.

Table saw
This is not a particularly difficult job on the table saw, with a well-made crosscut sled and dado stack.

Some additional support to the left of the blade¹ would be helpful, but all you really have to do is firmly clamp the workpieces to the rear fence on the sled if you're careful.

You could do this on the TS without either a crosscut sled or dado stack, if you take your time and pay attention, and as long as you can attach a tall fence to your mitre gauge.

Router (table)
Using the router table is arguably not the ideal way to do this, regardless if it's basic or fully featured, because of the amount of support the long shelves require. But it is doable especially if you can arrange additional support to the left and ideally can clamp the workpieces to a tall fence.

Another idea I had would be to clamp up the bottom two shelves and use a straight cut router bit with a guide – but consistency might be a challenge?

Consistency with a router in this sort of situation is merely a matter of careful setup and firmly clamping your stop(s).

But a straight-cutting router bit will naturally leave rounded inside corners on your notches. You will have to either go with these, and round the relevant arris on your frame², or square those round corners on the shelves by chisel or with a corner chisel.

By hand
These are bread and butter for hand tools, saw and chisel. After careful marking out of course, you saw the bulk of the waste away and then (if necessary) pare to your layout lines; if your sawing is very good all you'll be using the chisel for is cleaning up the inside corner.

Traditionally you might be advised to gang the shelves together and do each corner of all of them together in one go, but many people would prefer to do this one at a time. Takes longer but much less chance of a screw-up that affects more than one shelf!

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¹ Assuming the fence is at the right.

² Another possibility is to lean into it and round all of them to add an unusual feature to your shelves.

Answer 2

If you have good and are reasonably comfortable with hand tools, that'd be your first option. You should be able to saw the corner notches very nearly to the line with a carcass or good Japanese Dozuki or Kataba, and then pare to the line with a sharp chisel. If you're not fully adept with those tools, do some learning notches on scraps to get a feel for what works. Someone who regularly works with tools can build the required muscle memory and skill to get very solid results quite quickly.

If you really don't want to go the hand saw route, consider sawing with your jigsaw using a fine tooth blade nearly to the line, and then cleaning up with a paring chisel cut, as above.

In both cases above, if the chiseling is intimidating, consider using a clamped guide block on both sides of the cut, and a wide chisel. This can be a real skill and confidence builder.

If you are determined to go all the way with power tools,and have a bandsaw and supports adequate the for the large shelves, then the corner cuts are very simply fence guided notches. With a an appropriate blade, this would get you fast, reliable results. Assuming you don't have bandsaw, I would seriously consider building a router jig that clamps to the shelf to provide a flat surface perpendicular to the shelf - similar to a mortice jig for routers - and cut them that way. That'll give you the control you need to get a good router cut. You'll also want to clamp to the line of the cut on both sides of the plywood to prevent the router bit blowing out the veneer on the shelf.

I most definitely would not try to make the cuts with a table saw, using either a dado head or blade. You cannot control the sheet good adequately to safely and accurately make those cuts.