It was iirc a 1/2" ID collar from Grainger w a setscrew on the side. I slid it on the end of the shaft then snugged up the setscrew just the right amt so it would move with some pressure then set the dist down/into the inter shaft slot and it pushed the collar up the exact amt to give zero play then I carefully lifted the dist out and fully tightened the setscrew. My (most) dist tangs on the end have alot of play in the inter shaft slot and this (& a new chain) took care of it. If you LIGHTLY twist the rotor back/forth (not enough to get into the springs) you will see how much play your dist/inter shaft has and this slop will show up as spark scatter. I dont have the extra Grainger collars in front of me to give you a part # but They're a national chain & I think it'd be available online