Question

what is never to be engaged when using power tools?
booster
bit shank
trigger lock

Explanation:

When using power tools, the trigger lock is a safety feature that should not be engaged. The trigger lock is used to keep the tool running continuously without having to hold the trigger. However, this can be dangerous as it can cause the tool to start unexpectedly or continue running when not in use. The booster is a feature that provides extra power for tough jobs, and the bit shank is the part of the bit that fits into the tool. Both of these are necessary for the proper functioning of the tool.

Answer:

trigger lock