How can I remove material from this wood beam?

Question

I am trying to mount a roller shade in between two wood beams on my porch. The problem is that the beams are a hair too close together to accommodate mounting the shade.

I am trying to remove a small amount of material (~1/4") from the side of each wood beam, about 3 inches deep. I've illustrated the problem on this picture.

I'm unsure which tool or approach would be best to complete this job. I've considered a few ideas:

A straight router cut with a guide on the outside could do it, but the depth of cut I need extends past the capacity of most routers. I suppose I could hammer it out with a chisel but it would take a lot of effort. Another idea I considered was using a power planer to shave off material in large passes, but that approach poses problems considering I'm trying to remove material to a specific depth.

Anyone have suggestions?

Answer 1

What about trimming the roller shade? Most shades are meant to be trimmed, since manufacturers can't make every single size. See if you can pop off one of the ends, and then cut the rolled-up shade with a utility knife or something similar.

Answer 2

Trimming the roller shade is obviously the right answer, but just in case somebody has a similar problem where it isn't the right answer:

Don't try and create a router cut 3½" deep and ¼" wide - create one 3½" wide and ¼" deep. No router will have a problem with that. Probably easiest to clamp a piece of scrap to the outside of the beam, and then just cut the (wide, shallow) groove out.

(This does assume that you can remove the insect screen before cutting the wood out.)

This will, of course, not cut the bits at end. For those, you will need to get as close as possible with the router, and then finish off with a chisel (or a variety of chisels).

Answer 3

If you really want to cut that rebate, you could use a hand-held circular saw, you'll probably need one with an 8" or bigger blade to get the depth, to get a straight cut fix a staight-edge for the foot of the saw to follow. finish with chisels or an oscillating blade tool.