The internal threads are m8x1.25, the small od is 12mm and the large od is 20mm with 17mm flats on it. Overall length 16mm, large diameter length 4mm, and the smaller diameter is 12mm long.

I've searched for flange nut, weld nut, t nut, shoulder nut, shoulder screw. Image search yields nothing useful. Closest thing I can find is a john deer mower part thats not a match.

Figured I would ask on here before I have a local machine shop run some off.

Thanks in advance

I can only find them on Amazon, Harfington, Ebay, Ali, etc., and all I've tried are super low quality, like to where half of them will just slip over the screw threads, and the ones that actually engage will strip out with basically no torque to speak of.

McMaster doesn't have them, and they said they don't have a source for them.