i'm working on a spindle for a chair so what's going to happen when this is all done i've got to have a tenon on each end that perfectly mates into a hole i drill in the chair itself i want to make sure i have a good fit chairs take a lot of abuse so i need to make sure that when i turn the tenon on the end of this it's going to perfectly match the hole i drill in the leg of the chair one way i could do that would be using my parting tool and my calipers i can set the calipers to that diameter carefully test as i go i'm going to demand a little bit more accuracy on this i want to make sure i have a great fit so the way i'm going to do it is using this block of wood what i've done here is took a full-size block drilled into it a one-inch hole then i cut the block in half so now i've got kind of a go no go gauge for my tenon that i'm working on here i've labeled it as one inch so when i use it for other projects i already know what size it is the way i'll use it here is make cuts test the fit make cuts test the fit until i get this diameter on my spindle down to a point where this perfectly straddles that material here's how it works uh that's a perfect fit i know that that end is going to go right into the one-inch hole i'm going to drill on the leg it's going to be very very strong because i'm going to have a great mate between the tenon and the hole remember as you're dialing into that final final size that when you cut you're taking off twice the amount of wood you might think you are in other words if i'm peeling off a 32nd from this side i'm affecting the overall diameter by a 16th of an inch so very very light passes at the end to sneak up on that final setting but this is a very easy way to make sure it's dead accurate you