These spot weld cutters feature a centering pin but will need help to stay on track. That said, enlarging the impression with a small drill bit may prove invaluable. The jagged teeth can make it ...

[Aaron Christophel] has a battery spot welder that costs a not unreasonable 30 euros and can also be used as a novelty power bank. He subjects it to a test and teardown in the video below the break.

This spot welder may still be dangerous, but it looks like they took some precautions to make it non-lethal, and that counts for a lot. After their extremely questionable high speed belt sander, ...