Excellent tip

You mean to avoid buying a $20-25 pre-packaged part that is an EXCELLENT value I can:

Buy a $3 thrust bearing (plus lord knows what shipping...and time spent farting around trying to find/source one).

Ruin a $18-20 reamer

Have a part that maybe sorta works, but is anything BUT precision.

OR...call/e-mail Slapmaster (or Ashford Hobbies, or...), pay $22-25 (shipped!) via PayPal and receive a precision part in the mail that takes me a whopping minute to install. And my reamer still cuts ROUND holes in bodies like a hot knife through butter.

The economics defy me, and I'm never a fan of mis-using tools, but if your method works for you all I have to say is FANTASTIC!! Good on you. Like I said...I could cut one or a dozen proper spacers (as Arn0 has done) on the Sherline lathe, but for as cheap as these really are (and as long as they last) it ain't worth the set-up/clean-up, much less the time to make the piece and the material.

I would suggest, however, that you'd find your "sweet spot" would be a bit larger if you continued to run the Belleville washer for some "spring" effect/tensioning. The reason Brian selected Delrin was for it's inherent elasticity characteristics (spring-like qualities...takes place of Belleville).