If the tooth was one off on one gear, the center to center would not form an = triangle and you would not be able mount the transmission to the pins.
Mr. Redmodelt, I didn't say anything about being one tooth off. If the transmissions teeth are wore, so will be the drum teeth, and drive gear with enough slack at some point, can, very easy, can be set up, out of time. I have seen many of tooth as sharp an a knife blade.
Some triple gears, the time marks are stamped so light, that they are non-existent. The riveted triple gears, are good for this.
You don't have to use the time marks to get the gears in time. If you don't have marks, start off with any tooth, and put one gear on with the same amount of tooth on each side, of the tooth in the center, and make sure the gear is held there, so it won't fall off, and you have to start over. You can mark the same tooth on the other gears, but that sometimes is also hard to do.
So you have one gear on you picked for a standard, take the next gear, and go around the Drum about a 1/3 of the way, put the gear on like the first one, with a equal amount of triple gear tooth, on each side of the drum gear. Go to each tooth, and the one that has equal tooth on the drum gear, and the bushing is equally spaced with all 3 gears mounted to the drums, and the triple gear bushings are dead center in distance in 1/3's, will be timed.
So if there were time marks you can see, they will all be timed when they are turned to the marked position.
That's probably clear as mud, but try it when you are just playing around.
Herm.
