You have a 205 - 12 Plain Cintimill 1971 .First thing i want to tell you, never make a shear key with harden stock. You will shear the shaft end points and not the key.
You problem is someone has mess up your timing of your feed gearing. You can pull the front bracket and time the gears where you can see it, I can do it with the front bracket in place. One problem this way you have to put 1/4 20 treads in the center of the feed gear change shaft. You have to knock the role pin out of the gear change handle and be able to hold the shave from going inside the front bracket. Once the 1/4 20 threads are into and up to the pin hole, that is far enough. I usually use a small allen wrench and go through the pin hole and screw the allen screw against the allen wrench. Not much threads to use, but it works. With the machine running you use the allen wrench to turn the feed change. You can feel it going into a speed gear and across and leaving that gear.You then move the handle holding the allen screw in and rotate the shaft a little and bring the shaft back toware the front and engage the gearing again. Keep doing this until you get the right gear to run all the feeds as you put it in gear and the locator hole at the right feed. You may not understand this, Maye you will. Anyway your gear box is not timed correctly.I have Pub, number manual B -109 - 5 Page RP 8 item 7 (shaft )and RP 12 item 43.
What should happen with each rotation of the speed handle and let the spring loaded pin to drop into to one of the two spots and have a speed each time the pin locates.
