Key way and Set Screw orientation

[Ray C]

+1 on not using loctite anywhere near plastic. I had a medical device product that was made of a very durable plastic material which had a brass insert molded into it with a set screw and lock nut that adjusted a flow rate. The hospital repair technicians got into the habit of throwing away the lock nut and using loctite on it and it lead to 100% failure rate of the plastic component in a few month's time.

Ray

I'm leery of locktite with anything that has plastic - I've seen it destroy a plastic part in anywhere from a few days to a few months, so I don't think I'll use locktite. As for having one under the set screw, that would certainly be a location that I would prefer, but I'm not sure that there is enough material to allow the keyway and still have meat enough for the setscrew, since this is a metal hub in plastic pulley. I do have another all aluminum pulley with a larger hub that I can use if I have to, but I wanted to stay with the plastic one, to start with anyway. I'll do some measuring and see what will work out. I may look into setscrews that have a patch of locking material on them, since I beleive the problems that I have seen in the past with plastic parts is more due to the solvents in the locktite. Thanks for the suggestions!
Dan

 

[SEK_22Hornet]

While not the ideal solution, I believe I have it holding, at least for now. I ended up going to a 10-32 cup point set screw and set it directly into the 4mm keyway of the motor - it is a snug fit and it seems to be holding. I have ordered some 10-32 set screws with the locking patch on them and will try one of those. Unfortunately, there isn't enough metal to add a lock screw. If this doesn't hold, I'll go ahead and modify the all aluminum pulley with a proper keyway and set screws at the suggested locations. Thanks for the suggestions!

Dan