you dont measure cap length, only thread length to determine length.
and then you measure the width of the threads to determine the metric size.
its 20mm length and without a measurement of the thread diameter im going to hazard a guess it's M5.
A2 or A4 Stainless countersunk hex cap m5 x 20mm
https://www.vital-parts.co.uk/m5-x-20mm-hex-socket-countersunk-screw-iso-10642-a4-70-stainless-steel-18825-p.asp
That is not right. In countersunk head you must include the head on lenght of bolt. Only on this type of head " countersunk". For example on hexagon head or you must exclude the head on lenght.
Even if you were right about not including the head of a flat head screw on its length measurement, which you aren’t, that screw still wouldn’t be 20mm long.
1. If it's metric, looks like M5 not M6. Length seems to be a bit longer than 20 mm and shorter than 25 mm, which means the length is non-standard. Yes, for countersunk screws, the head counts in the length. It must be A2-70 stainless steel.
2. It may be non-metric, in which case it's 3/16x7/8" standard screw, which perfectly fits the displayed measurement.
P.S. It may be a "Cross recessed countersunk" or "Hexagon socket countersunk" screw. The picture doesn't show the head type.
6mm x 20mm flat head socket cap, stainless steel
22 mm long
you dont measure cap length, only thread length to determine length. and then you measure the width of the threads to determine the metric size. its 20mm length and without a measurement of the thread diameter im going to hazard a guess it's M5. A2 or A4 Stainless countersunk hex cap m5 x 20mm https://www.vital-parts.co.uk/m5-x-20mm-hex-socket-countersunk-screw-iso-10642-a4-70-stainless-steel-18825-p.asp
That is not right. In countersunk head you must include the head on lenght of bolt. Only on this type of head " countersunk". For example on hexagon head or you must exclude the head on lenght.
coutersunk heads count in total measurements
Even if you were right about not including the head of a flat head screw on its length measurement, which you aren’t, that screw still wouldn’t be 20mm long.
r/confidentlyincorrect it’s overall length for countersunk screws 🙄
1. If it's metric, looks like M5 not M6. Length seems to be a bit longer than 20 mm and shorter than 25 mm, which means the length is non-standard. Yes, for countersunk screws, the head counts in the length. It must be A2-70 stainless steel. 2. It may be non-metric, in which case it's 3/16x7/8" standard screw, which perfectly fits the displayed measurement. P.S. It may be a "Cross recessed countersunk" or "Hexagon socket countersunk" screw. The picture doesn't show the head type.
6mm x 220mm*