chalk fitting

[Larry Simonson]

Hi, I'm presently fitting the neck (Siminoff ) joint on my 3rd build and think I know what "chalk" fitting is, but I might not, so if someone wants to give either a short or extensive tutorial on that subject, I would appreciate it. Thanks

[Wspur]

Me too! I don't even think I know what it is, but I think I need to know what it is. I think...

[michaelcj]

Whether with dovetail joints, fitting violin/mandolin bridges or any other joint chalking is a way to incrementally fit the joint as close to perfect as possible.

In a dovetail joint, for example, the bearing surface of the "female" dovetail are lightly but completely covered with chalk. As the male dovetail is inserted the chalk will transfer to high spots on the male dovetail. these transfer areas are pared away carefully,tiny bit at a time and the joint rechecked and retried. Each time small shaving at the high spots….over and over…until the joint goes fully home and there is a consistent transfer of chalk on the mating surfaces.
Can Also be done with transfer paper which is a very thin carbon paper.

The idea is to careful and incrementally pare away the high spots till you have perfect mating surfaces.

Bet you could find a you tube that showed the process.

[Willie Poole]

This can also be done when fitting a bridge to the top of a mandolin to get perfect fit.......

Willie

[tom.gibson]

With the 'Siminoff' joint (or tapered mortise and tenon, violin neck joint or whatever) I've done the chalk fitting the other way round. Get the neck part of the joint to a perfect taper, then don't touch it again. Put the chalk on this part of the joint, press into the body mortise and gradually enlarge the mortise, removing the chalk marks with chisel, scraper, sanding sticks etc. I think this way works better, since the neck part of the joint can be more easily cut to perfect accuracy than the mortise. My 2c.

[kjbllc]

get pure chalk, with no fillers, you don't want to make it unglueable

[pointpergame]

It's worth reiterating that some dovetails are best fitted with tapered joints. From cutting drawer dovetails for a long time, it took me forever to get my head out of the box and realize that fitting these single-unit joints ( or the huge dovetails like those on the end vise of a workbench ) required tapers. Otherwise you trim, trim, and then it's too lose. It seems blatantly obvious in retrospect.