reinforced miter joints

I've made several boxes with keyed miter joints, as you are doing, and I have always used keys with the grain running perpendicularly to the back of the slot. I don't think it would really make a difference because the strength is coming from the side grain being glued to the edges of the slot you cut. So, basically, it comes down to what you think looks best.

And, speaking of cutting the slots, I'll reiterate the comments of other posters that Man! that sure looks like it could be dangerous. If you have a router table, you can make a sled and use a straight bit to cut those slots.

Nice looking box, by the way!

Jim

"feature opportunities"

My folks gave me a Barnes and Noble gift card for the holidays and I went and picked up Gary Rogowski's "The Complete Illustrated Guide to Joinery" yesterday. It turns out my joints are keyed miter joints, not splined - apologies for the incorrect terminology on my end.

Now, as for the actual project, It is time for me to add some features to my box. I tried using a flush trim router bit to clean up the purpleheart keys and now have two "feature opportunities," otherwise known as issues. First, my miter joints are apparently not perfect. I knew they weren't perfect 90 degrees but apparently the box walls didn't make perfect 90 degrees to the horizontal either, as the bit scored parts of the walls. This problem alone could be solved with some quality time on various sanders.

The more significant feature opportunity is that two of my keys lost a bit of corner material during the routing. My flush trim wasn't tall enough to trim both keys at once - the first corner loss occurred during the unsupported anti-climb cut. After that I used climb cuts for the unsupported cuts, but the damage is done.

I was initially thinking to cut a miter off of each corner, but my base is already constructed using a mitered frame and a floating cherry ply panel - if I cut a miter off each corner I think I may have an issue. My RAS is still setup for the key slot cuts, so I think the best thing to do is partially recut the key slot and glue in a replacement key.

Any other suggestions would be appreciated. Thanks!

I went ahead and recut slightly smaller (than original) key slots for secondary keys at the damaged keys. This time after trimming with the bandsaw I will use the oscillating belt sander for final flushing, then the random orbit for pre-finish sanding.

One of the key slots was cut slightly overwidth during setup cutting - I added some excess glue to dribble into that slot this time - it is going to be noticeable that an error was made and hopefully a little extra glue will add strength to the key. Live and learn. I know I could have maybe mixed some purpleheart dust into the glue, but I'll just make this the back. It probably happened on the side with the more interesting grain I wanted to be the front. Oh well. If the overwidth key slot is on the top, maybe I'll make the lid slightly proud of the carcass to distract the eye from the error.

Speaking of the lid, I'm going to hinge the lid to the back. Since I've used miter joints, the lid grain should run side - side so that the hinges attach to the same grain orientation of the carcass and lid, right?