+1 on what @rod90 said. McMaster should have what you need. If not, there is a website that when you input the measurements it will generate an STL file. stlgears is the name of the site.
Mikes Arcade has what you need
https://mikesarcade.com/cgi-bin/store.pl?sku=MONMNTN
https://mikesarcade.com/cgi-bin/store.pl?sku=MBEZBRKTN
https://mikesarcade.com/cgi-bin/store.pl?sku=MBRKTOPN