Nothing wrong with a homemade compressor if done correctly, I built a large one using a Broom and Wade compressor when living down south and it gave great performance. The receiver is something that will contain stored energy and needs to be sound, just a fitting letting go can cause some horrendous injuries
The other very important device is the safety valve, this must be fitted and tested to work as it will open at a setpoint to prevent exccess pressure from building up that could result in a failure of the air receiver and with explosive results, you cannot rely on the pumps limations or that it will stall. On my setup the running pressure was 185 Psi, cut in pressure was 170 Psi and safety valve opened at 195 Psi.
Unless they were welded by a qualified person and it can be proven then walk away, most receivers will have mounting platforms already attached onto which you can sit the motor and compresspr pump but not cylinders designed to store gas.Looks like the upper and lower brackets have been welded to the gas cylinder tank
The other very important device is the safety valve, this must be fitted and tested to work as it will open at a setpoint to prevent exccess pressure from building up that could result in a failure of the air receiver and with explosive results, you cannot rely on the pumps limations or that it will stall. On my setup the running pressure was 185 Psi, cut in pressure was 170 Psi and safety valve opened at 195 Psi.