Sky watcher secondary screws question

[5ash]

Hi, does anyone know the size of the thread on the 3 screws that adjust the secondary mirror on a 10” skywatcher flex tube Dobsonian. I want to make something similar to bobs knobs
Philip

[5ash]

OK found out by removing one screw and going through my collection of screws. Its an M4 screw. Have ordered some suitable M4 barrel knobs from eBay.
Philip:)