Would be surprised if they used a 5. Could be a 6 which is only .138 Dia. Just buy one of them all and see what fits, they are pretty cheap. Small and long is also hard to find. Fine is sometimes difficult to find locally.
Unless someone wants to unscrew their 80 year old screw and measure. Engineers try to use the same size for lots of things to save money. Might there be another interior part that uses that screw so you can size it? What head configuration do you think it is? Pan, Flat...82deg...100deg?


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