#16 is a
slotted cheese head metric, not hex Mark/Mikey914, & not Phillis Mark.
Phillips will cam-out before you get enough TQ on them to keep them in place.
Germans apparently transliterated that to "pan head" - which I associate with a low rounded shape like the inside of a frying pan - but the
originals on mine were cheese head, which are flat around the edge circumference & about 1/16 - 3/32" tall (as shown in the diagram if you zoom in) - & those give a bit more "meat" than a pan head for the screwdriver to bite into while torquing down or loosening them.
Also, #13 is a black nylon/sim. spacer-washer about +/- 3/32" thick, which are harder to find than white ones (I just looked for similar ones in white for my Westy table locking bolts, but saw no black).
I think the AA & maybe A&P Girl (Mark's link above) & maybe others carry a "kit" for this hardware. I got the AA kit a while back to make it easier for me.
If you want to do the hunting yourself & aren't particular about being a bit off of originality (e.g.: hex instead of cheese head screws, etc.), then you can run the parts down using the PET descriptions at any old school hardware store(s) &/or online supplier(s) that stocks metric in a wide variety, but it will probably take you more than one source.
Sometimes it's just more cost & time effective to let someone else who's done all the sourcing on a wholesale basis to sell you a kit for a bit more than you might pay for the parts yourself
+ hours of running them down yourself.
Cheers!
Tom
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