To Controlliner's Q: in Post 10 -
In the USA, at least, there are still a few "hardware stores" (UK equiv: 'ironmongers' ?) which sell small parts loose, I..e., not packaged in always the wrong number of pieces. ( 3 bolts or 12 bolts in shrink-wrap when you need but one... or 4.) In the "fasteners" section you can find bins or drawers of individual iron washers in many diameters and thicknesses. ...and much else. The clerks never seem to mind when I bring, e.g., a PAW to find which iron washer has the best diameter and thickness for correct fit, or which small Phillips head screw driver fits an odd small metric screw...Or which metric or SAE thread comes close to fitting some oddball Pacific Rim or Eastern European thread.(Some come very close!)
The first few times, I made sure to ask the section clerks where I could find things, so they'd know I wasn't trying to sneak something by. By now, they recognize me and let me dig.
I would rather clamp a properly fitting iron washer in a vise, than ANY part of a model engine. My old, old Unimat mini-lathe would probably withstand using the 3-jaw as a clamp, but if it doesn't, a replacement part will be very hard to find...And yes, each PAW engine size will need its own "best fit" washer for the job, possibly excepting their .15 (2.49) and .19 engines...