Making a square - Joining two pieces of wood cut at 45 degrees with a circular saw

I am trying to create a 90 degree angle from two pieces of wood so that I can eventually create a squared enclosure. I have cut two pieces of wood at 45 degrees with a circular saw's angle adjustment.

However, when I try to join the pieces of wood, they only meet at their tips and not throughout the slope of the cut (see photo below). Because of this, I can't figure out how to nicely join them together while ensuring that they will have a 90 degree angle when they are merged.

What is the recommended way join wood in this way to create flush 90 degree angles for a squared enclosure? Is it possible to do this with a circular saw?

• I bet you're misreading the scale. Commented May 8, 2018 at 4:18
• Are you using a bench-mounted "chop saw" or a hand-held circular saw? Commented May 8, 2018 at 9:42
• If you are using a compound mitre saw your tilt is not set at zero
– Kris
Commented May 8, 2018 at 12:18
• ... or the paper on which the pieces sit has them tilted. :) Commented May 8, 2018 at 14:00
• Frames are difficult even with a miter saw. I'd never attempt them with a circular saw, which aren't designed for that level of precision or that type of cut. I'd use a handsaw and a simple miter box/jig first. Commented May 8, 2018 at 14:01

You need to adjust your circular saw to an actual 45 degree angle, not to where the scale markings say '45'. Your speed square will do the trick.

(Or redesign for butt joints and skip the bother of a circular saw for 45s like that...)

edit to add, I tend to avoid cuts like this with a handheld circular saw because they are hard to do well, but you can improve the cut by concentrating on keeping the large part of the shoe (aka sole/deck) flat on the wood, and using something like your speed square to guide the saw to a smooth 90 degree cut.

• I picked up some wood and redesigned it for butt joints. They aren't as aesthetically pleasing to me, but that isn't super important for this project. I have had this issue with angles not matching up in the past with this saw; good to know I just need to calibrate the saw to an actual 45 degree angle Commented May 8, 2018 at 17:48

I assume you are using a miter saw and not a hand held circular saw, right?

The cuts might be almost exactly 45 deg on each of the cuts, but if one of the four pieces is slightly longer than the piece opposite, then you would get exactly what you show in the picture. So you could try taking a little off the top piece.

It is not that hard to cut exact 45 deg angles with a power miter (circular) saw, but it is not as easy to get the lengths exactly right. You could measure the lengths of the four pieces and put the closest matches opposite.

• I'm not sure that's a safe assumption. Commented May 8, 2018 at 13:31
• The OP says circular, which implies hand-held, not miter Commented May 8, 2018 at 13:47
• It's a circular, hand-held saw; not a miter. I'm thinking that for future projects that involve these cuts, I should get a miter though. Thoughts? Commented May 8, 2018 at 17:14