Pulley wiggle-key tolerance AND - shaft end Loctite

I think you're overthinking this.

You could leave it, shim it or loctite it all with the same end result, you will forget all about it in a week and it will be fine regardless of what you do.
it's true, I am, there is a reason for it. Part of the reason is I need friends to help me out with assembly due to reduced mobility. So I want to get it right the first time. I feel like shimming would actually be the easiest. But have to have the thickness correct

You haven't posted a picture of the shaft that the pulley sits on. I would expect that shaft would have a shoulder that the pulley rests against, and a slightly smaller diameter section where the pulley sits that is slotted for the key. From your description I think you are saying that there is a bolt going into the end of the shaft, and a washer on that bolt is holding the pulley onto the shaft?

If that is the case, I would suggest either shimming between the pulley and shaft with a thin washer. Another approach, if my understanding is correct, would be to simply file the end of the shaft to remove 10-20 thou so that the end bolt and washer put pressure on the pulley. Possibly add loctite ...

I understand now. Yes there is a shoulder on the shaft. There is also a bolt on the end as you can see from the pics. how would adding a washer Against the shoulder tighten everything up?I don't think the screw was bottoming out
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Make a key to fit. Milling machine not required. Buy a 6" piece of key stock the next size bigger. Vice grips and any means of grinding, or a vice and a file. (the long key stock lets you screw up a few times!)
 
If the bolt is bottoming out in the hole on the end of the shaft rather than against the washer, you ideally want a slightly shorter bolt, or a deeper hole. Have you tried to blow the bolt hole out with air? If that doesn't help, you could run a bottoming tap into the shaft, or easier yet, just add another washer between the bolt head and the pulley. You can stack washers, maybe not ideal but it'll work fine.
 
Thank you for the pics. The shaft‘s shoulder is mediocre at the best, not much locating surface for the pulley to rest against and possibly the pulley is going past the shoulder. In a case like this, I usually add a hardened washer with a same inside diameter as the shaft, (within .005 clearance), and a larger outside diameter than the shoulder. Do you know the shaft diameter? The washer shown also has too small of an outside diameter and could be thicker. Also, it looks like there is a raised section in the shaft diameter near the shoulder. If so, could you clean that up with a file so it is flush wit the shaft. More to come.
 
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Thank you for the pics. The shaft‘s shoulder is mediocre at the best, not much locating surface for the pulley to rest against and possibly the pulley is going past the shoulder. In a case like this, I usually add a hardened washer with a same inside diameter as the shaft, (within .005 clearance), and a larger outside diameter than the shoulder. Do you know the shaft diameter? The washer shown also has too small of an outside diameter and could be thicker. Also, it looks like there is a raised section in the shaft diameter near the shoulder. If so, could you clean that up with a file so it is flush wit the shaft. More to come.
shaft size is 12mm I can measure it to the nearest thousanth. the washer shown is actually deformed inwards and no longer flat. the parts list states a "M6.4 FLAT WASHER"
 
Can you get a 7/16” hardened washer, (grade 8), to put against the shoulder before putting the pulley on. The one that I have here is just over 12 mm, (see picture). Then use a couple of 6 mm fender washers under the bolt to replace the deformed one. Should help a lot.
May need to add same thickness washers to the other pulley(s) for alignment.
 

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