Gosh, most hardware stores have little trays full of them. Mylar or brass. Avoid shimming too tight, as that will put excess wear on the latch.

Another approach is buy the thinnest brass washer you can find - too thin to do the job alone - bend it into a curved spring washer, then bake in the oven to set. (15 min at 350F)

You could also place you home-made thrust washer at the bottom of the spindle to push the spool up into the latch.

JW Young did this for most of 100 yrs on thumbscrew reels.

https://www.mcmaster.com

McMaster-Carr. Any small hardware you can dream of.

Hi Ron,

Bolt Depot is definitely another favorite (along with eBay). I just purchased a bunch of hardware from them to use on a utility trailer project. But, you're right: sometimes you have to bite the bullet and buy a larger quantity than you might need and/or pay high shipping from McMaster-Carr to get that hard-to-find hardware.

I live in the sticks and have to drive 25 miles, one way, to get to a decent hardware store. That often makes on-line orders, even from McMaster-Carr, a reasonable choice for me when I need some specialty item.

Radding, I've had the same problem on both of my 67SS reels. I have some
10 ths brass and copper shim stock and it worked fine. I used a punch to make the spindle hole. Its thin enough that you can easily cut it out with a small exacto knife. Might not be a perfect circle but it doesn't need to be. The outside just use scissors. It was a bit to thick so I just made a second one and gave it a few wacks with the hammer to thin out and cut a new one. Send me a PM and I'll mail you some.

Newmin

Nice outcome! Finish by PM, please.

Just a comment, the need of a shim isn't a "problem." Actually, sometimes micro tolerances cause more problems because the least bit of fouling, let's say from congealed, dirty lubricant or mineral fines deposited after water evaporates, can cause wear or poor operation. Things run smooth until they don't. And those "tight" tolerances add to production costs. Martins may seem all loosey goosey by comparison, but they may not decades later, and individual parts can be mixed and matched for functional fit. In the case of shims, these were provided on some Martin reels right from the factory. Here's an MG-3 with one. Also shown from another reel is a shim removed to show separately.

A relatively coarse click is the old-school way of providing the much-touted "low start-up inertia," that still is less than ideal in disc drag reels that use any kind of spring-loaded brake to apply continuous pressure. Minimal, very low start-up is inherent in a pawl-gear (click-pawl) design. At rest, the spool is, essentially "free" spinning for that slack point in the pawl-gear engagement. Thus, the spool goes from minimal to gradually building resistance as the pawl rocks on the gear and peaks before it slips to the next tooth, meeting it higher on the tooth than at start-up, so resistance is slightly greater. This continues for the first few engagements, then stabilizes with steady spin--unless the run is so fast that the gear floats the pawl. Now the spool has built momentum and stops gradually--a click or two--if the fish stops, easing the suddeness of sulk-bolt and run-stop-run. A "low inertia" position is inherent in each change of speed. The resilience of 'glass makes it an ideal combination with the simple, reliable, click-pawl mechanism. Definitely, the sharpness/thickness of the pawl affects start up feel and can be fun to tinker with. The gear, of course, is a fixed component but different brands/models of click pawls are fitted with gears from very fine-toothed to quite coarse. The width of the teeth and pawl is yet another factor.