I've gone into more detail on neck resets in other posts, so I'm not going to repeat it all here. I calculated the amount of material to remove from the bottom of the heel, using the Erlewine neck reset formula. It came out to .02 inches, or about .5mm. I'll take that amount of the bottom of the heel, and then gradually less as the heel goes up toward the fingerboard. Think of it as a small thin pie shape.
Mmmm. Pie. Maybe you don't want to think about pie when you're doing this. Just saying.
Then I just made an angle cut across the heel to serve as a guide as to the depth.
What I did was use a file and take off a tiny bit - 4 or 5 strokes at a time. Then viewing it from the bottom and the sides, I could judge how much was coming off.
Remember, you can't put material back on.
This is a tedious process - a couple file strokes, eyeball it, then test it on the ukulele.
This is another back-and-forth, test the fit operation. It take a while, but soon the fit will be tight and the angle will be correct.
I used 220 grit paper for this - I wouldn't go below that or you may take too much off.
I heat up my hide glue (it's in the white container on the left). And I gathered up some cauls and clamps. I strongly suggest doing a 'dry run' before you actually glue it all up.
You'll also see the heat gun on the lower right in the picture. I like to warm up the joints before I glue. Hide glue starts to set at a temperature of 90 degrees F. If the joint is warmed up a bit, you have more time to work before the temperature goes down.
After having cauls fall off many times just when I was about to clamp them down, it finally hit me that I should tape them down! That's the blue tape in the pictures. I 'destuck' it some on my shirt first so it wouldn't hurt the delicate finish. Then when everything was clamped up, I took the tape off.