The slot machine is A very handy tool and I use mine very often. I also bought a slot cutting guide to use with it. {sold at most hobby stores} I can't remember if it came with the two sizes of blades or not, I think so but I have bought more blades for it over the years so not sure. The thin blade is for CA hinges and the thicker one is for the plastic types.
The only bad thing I can say about it is it does not like to cut any type of hard wood, even hard balsa or go through the CA glue when I add balsa sticks behind the hinge points. The CA may harden the wood too much??
I think I have used mine on every plane I have built except one and that plane I used all hinge points.
A very handy little tool!!