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Over here on the operators side of the jig I've got a gear blank with an index wheel attached to it.
And the gear blank itself rides in the gap between the baseboard and the backboard.
And the index wheel stays on top of the baseboard, and rides along this strip of sandpaper I've got glued down.
And here next to it I've got a piece of tape with index markings that line up with the marks on the index wheel.
The marks on the index wheel, there's one for each tooth. This one will have 28 teeth.
What we first do (and I have already done in this case) is make a cut in the center of each notch between teeth.
I didn't want to cut away the index mark if the blade cuts into the index wheel at all, so I put it (the kerf) halfway between.
So these two marks down here line up with two marks on the wheel.
I just line these two marks up with marks on the wheel roughly and I just push it straight down into the blade until it bottoms out on the index wheel.
And then the next set of marks, I've got two over here and two over here...
The two different marks are to compensate for the thickness of the blade, the blade kerf.
If I just used this outer set of marks, the notch would be too narrow and the teeth would be too fat,
so I have to measure the tooth thickness and figure how much more I need to take off.
i'll split that number dividing it by two so I can make the adjustment on both sides so I can clean up both sides real good.
So I am going to cut a few teeth and show you how it works. I can since I've already got the center cut, and the teeth are not that big
I can make the rest of the cut with one pass on each side, so I'll do that..
Going to use the inner set of marks...
...and then line up the nearest mark on this end with the inside mark.
and that completes a tooth.
Now I am going to do another one.
Let's see what we've got.
Okay, here's the two (notches) I just cut. One tooth between the two notches.
So that's the proper tooth thickness, that's the width of the tooth along the pitch circle.
And I will just continue doing that all the way around to complete all 28 teeth, and that gear will be done.