Jig Question..

Someone posted a link to someone's site that had instructions for a do it yourself jig, and it is one I think I could easily replicate (crappy diagram below).

I just have to easy questions since I have never actually seen a jig in action...

I'm guessing the magnets should be aligned so that they grab at the center of the blade (as pictured in my diagram). Please correct me if they are supposed to be closer to the edge or spine of the blade.

Also, why is it the jigs have a ridge that the spine buts up to? Since every jig I've seen has it I'd have to assume there is a good reason for it.

The rail you talk about is to keep the blade from comming off the jig if you are using a rotary tool like a Dremel.
Also, concerning the magnets, you should use the metal cups that you can purchase for them. The cups will enhance the amount of magnetism of the magnets. Randy and I found that when we used the magnets without the cups, the magnets were attracted to one another and pulled through the wood. I believe in the Mac-Carr catalog it does mention how these magnets work and the reasoning behind the cups.

wow, thanks for the quick reply, that ridge makes a lot of sense now. As for the magnet cups, I think I can see the reasoning, probably works similar to the principal behind shielding in speakers.

Maybe this is the link you were looking for?

Bill's Straight Razor Info: Making the Blade Safety Jig