Picked up a 1964 Space Gun a few weeks ago.
Finally had some time to get into my Space Gun and there a number of clear issues. Biggest one is that when I opened the lower back door, the chain and plastic drive sprocket that spins the main target wheel were laying on the 'floor'. (of course this assumes this was the original chain and sprocket).
It looks like the plastic sprocket had sheared off where it aligned with the 'key' that sits at the end of the shaft.
Open to any direction/thoughts on how to fix or creatively work around this. I know I can buy 12-tooth sprockets, main question is how to attach it to the shaft. Threads you see in the middle of they key at the end of the shaft are 3/16".
Below is a image that also shows the lower sprocket which is attached to the drive motor.