Okay, so you need little 1.5mm bore thrust washers....
I use stainless and plastic ones I can scarf up from eBay, where they appear from time to time.
Here are some examples:
https://www.ebay.com/itm/285834876681 These are PTFE, so very strong and slippery plastic. You want the M1.5 x 2.5 ones, which
means a 1.5mm bore and an outside diam of 2.5mm. They are 0.2mm thick, so about .008"
https://www.ebay.com/itm/155979477420 Stainless, M1.5 x 2.5 also 0.2mm thick.
Northwest Shortline USED to be a premier source for these, but about the only size they appear to still be making that would be usedful
for N Scale are the 110-4, which are 1/16" bore (close enough to 1.5mm) x 3mm diam x .010" thick.
Another good source for these is old toy motors. Even junky motors usually have some thrust washers on the armature, so you can take the motor apart and harvest the washers. And they sometimes have really nice thin .005" ones.
The old melt-down Rivarossi can motors always had some thrust washers on the armatures, and they are almost always super-thin, like .003" or so, which can be really handy for getting an ultra-precise gear or motor alignment. You can get that "just enough to stop back-and-forth-wiggling-with-no-binding" when you start getting down to .003" thickness. They don't look like much, often appearing to be punched with in uneven amount of outside diameter. But they are hardened steel and work really well. So if anyone has those and is tossing them in the trash, steal the washers out of them first for future use.
As a bit of general advice - if you can use two thinner washers together instead of one thicker, always go with two thinner ones.
When a worm or armature is pressing up against a bearing and spinning, the two washers are much more likely to slip and spin free against each other than if you have a single thicker washer, which might just stick to the spinning entity (the gear or armature), and then spin up against the bearing. Not that that won't work, but two washers slipping and spinning freely against each other is better.
