None of the adapter brackets or plates I've tried handle the VESA 200x200 end correctly. The holes aren't large enough for the standard VESA 200x200 M8 screws, which seems really odd.
Background: I'm trying to mount a lightweight VESA 200x200 panel onto a monitor arm that has 75x75 and 100x100 holes.
22 Answers
Mount: VESA mounting standard MIS-F allows for 200 x 200 mm spacing of holes and specifies either M6 or M8 bolts.
Bolts: M6 bolts have a 6mm diameter shank, M8 bolts 8mm.
Holes: Recommended hole sizes are 6.4-6.55 and 8.4-8.55mm respectively. (ref)
Washers: M6 or M8 washers have an internal diameter of 7.0-6.6mm and 9.4-9.0mm respectively. (ref)
Hypothesis: Perhaps your "VESA 200 x 200" adapter plate is for M6 bolts and has hole diameter approx 6.5mm?
1You need a VESA conversion plate. Sometimes these are also called adapter plates.
Here is one at Amazon
It should work provided that your arm has enough strength to hold the panel.
1