Contact a good autobody shop that has a frame machine and have them look at it and give you their opinion.
No, but the frame of a metal house must be grounded to an approved grounding electrode.
As long as you disconnect the battery (or batteries) first, you should be fine. Basically, disconnecting at least the negative cable breaks the circuit thus protecting the electronics.
If you need to repair a metal bed frame, it may be necessary to use a welding torch. Be sure you know how to properly and safely operate it by consulting the manufacturer's instructions. Do not repair your bed in the bedroom-- take it outside or into the garage!
Either will work.
Anywhere on the frame, engine, or body (if the body is grounded to the frame in any way).
To my knowledge, there is no cable that grounds the starter to the frame. The starter is grounded when is bolted to the flywheel housing.
The spinning frame or water frame
Frame machines can be purchased online from retailers such as Amazon. One would recommend trying your local hardware store for a frame machine before looking online.
shure start welding axles and streching the frame......
A auto body repair shop with a frame machine can repair the frame.
water frame