How to setup CNC for making dog gears

[Veselin Kolev]

[quote=Travis Covington]
Centering the hole is done the same way as you would with any piece, but instead of an edge finder on an edge, you use the edge finder in the hole for both the x and y axis'. Or you can use a dial indicator and get the same result.
QUOTE]

Well, if you use the bore cutting function on a CNC, and using the same method that Travis described, all you input is an origin (0,0) centered between the aluminum jaws and have the radius be the outer radius of the gear, and let it cut away. After that, you just put the gear into the nice hole, clamp down, and if your CNC saved the (0,0) for the cut, you can use that for the center of the gear, since they are supposed to be the same. Thats how we did it, and we didn't get wobbley gears

Oh one more thing, you can use parallels for shims to put between the jaws; they work nicely because they come in lots of widths.

As for the cut in the gear itself, use some CAD softwear to get a list of coordinates that will cut the shape in the gear. CNC mills (at least ours) are easiest to work with when you're doing straight cuts from point to point. All I do sometimes is give my machinist a hunk of steel, tell him how wide, and give him a list of coordinates in order. Of course thats bad since he doesnt know what it should look like until the end, but thats why I usually give drawings too.

Hope that helps