Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

Throw the wood screw away.

There should be a female threaded bush in boiler
A male threaded plug that screws into boiler bush.
A hole from top to bottom in threaded plug .
A pin with a flat top that fits through plug from the top .
A spring fits onto the pin underneath the plug .
A nut holds the spring in place and applies tension
A o ring or fibre washer is sometimes used between the head of the pin and top of the plug
And a fibre washer between plug and boiler bush