I got to thinking that JimPend might know what he is talking about on the JB Weld, wing nut combo so I went out to the boat and looked at the removable service panel. Wing nuts would stick out too much and snag your clothes when you go down into the space to work on other things. It is a tight space in the rear of the cockpit where the steering, macerator, washdown pump, gen set Racor, etc are located.
I thought that I might make up a few anyway so I drove over to True Value. The problem is that the head of the screw will not fit down flush in the cradle of the wing nut that has the closest diameter to the screw. So that option will not work for two reasons.
What I am using now in lieu of the knurled thumb screws are regular stainless sheet metal screws #14 x 3/4". I took one of my remaining knurled screws to the hardware store to match it.
I need Knurled Head Thumb Sheet Metal Screws with Shoulder. #14 x 3/4"
I can't find them on the McMaster site or by a Google search.
Northern Lights may have me by the cahones.