I bought an oil sandwich plate for my oil gauges but the thread size is wrong. Replacement part costs $17.99 which i think is outrageously expensive. I was wondering if anyone knows where else to buy them at, and whether Home Depot stocks them? The size is 20 mm. Below is what they look like. Thanks in advance!!

 

Ack no one knows? I'm hoping this isn't a custom made nut for the oil sandwich plate...

 

What is that from? Different plates have different sizes.

 

Without knowing the model of the oil sandwich plate, there's no way to tell. The Mocal plates use 1/2" BSP thread. Although NPT threads will fit, they don't recommend it.

 

Yeah, BSP female doesn't work well with NPT male. You can go the other way safely though for some reason.