This pin is made of super-strong grade 12.9 alloy steel with a stainless steel nut. It's 3/16" diameter so the pivot-pin hole in your tube needs to be enlarged slightly for it to fit. The hole in the tube is 3/16" press-fit to hold split-pins and roll-pins tight. This custom solid pin fits a 3/16" slip-fit hole which is very slightly larger. A standard 3/16" drill bit can be used to enlarge the hole to the correct size.
This pin has a shoulder that stops the flat-side of the nut from threading too far in. The length in between the nut and head is 3/4" which is the same as the OD of the tube. This prevents the front of the tube from expanding when force is applied to the pump lever. This is the most stable pin design for this purpose, it also prevents over-compressing the front of the tube.