MIMF

I'm doing a kind of Les Paul style neck tenon for my current build, I normally do dovetail or bolt on joints. The tenon is straight, around 3" long, flat bottom, and straight flat sides. It will rest firmly on the bottom, and get clamped while gluing, but I can't clamp the sides. How tight a fit do I make the sides? I am currently doing the so-called final fit, shimming and filing to get the angle right, and the fit is barely loose. It slides in, but needs a bit of a push.

TIA, Brian

Water based glue will swell the wood a bit so you want a bit of looseness in the dry joint to allow you to get the neck fully seated when gluing. Sounds to me like you have it about right. You just need to work quick when setting the neck so you can get the clamp on and press the neck all the way down before excessive swelling blocks your progress.

Snug without being too tight. I like to be able to pick up the weight of the body, but I don't like forcing the neck into the pocket.