Help with a miter joint

I am making my first countertop but I’m not happy with my miter joint. Anyone have advice on how to improve it? I’ve cleaned up the cut with a flush trim router bit but it’s still not flush.

Sorry you’re having trouble. Miters cash be tough because if they aren’t perfect, it shows. When you say it’s not flush, do you mean the inside and outside corners don’t line up?

I mean that there is a gap running from the top to the bottom of the joint. If you see in the picture the joint is not touching.The two mitered edges aren’t closing up tightly.

I’m not sure why it’s not a tight fit. Impossible to tell from just a picture. Big picture, the edges either are not square to the faces or the surface they are resting on isn’t really flat. I can’t think of a reason that a flush trim bit wouldn’t make it square, but I guess it could happen depending on what was being used as a guide. If you hold a combination square to the edge, is there a gap?

I would first check that your cut is square, as in perpindicular to the top plane and then, that it is sitting on a flat surface and that neither end is bowed, twisted or otherwise keeping the mitered ends from coming together.

Thank you both for your help! I checked with a combination square yesterday and it wasn’t square. I bought a new router bit and hopefully that solves the problem. We’ll see.

Are you working on this at the makerspace? I’m doubtful that the router bit is actually a problem. Router bits tend to be near perfect unless they are old and used. More likely, an issue with the router itself not sitting down flat on the work piece or some other thing causing the cut not to be square

I looked at the pieces last night. The plywood isn’t cut square for some reason but the glued up tops appear to be ok. I’m not sure why that is, but it looks like it would be ok if the plywood could be squared up.

Thank you! I recut it yesterday and that helped some but yeah it’s still not perfect. I’ll see what I can do today.