Which of the following statements are not true?

1) Never use a grinder if its wheel is less than 1/2 its original diameter.
2) Never use a pedestal grinder if the wheel is not true.
3) Never grind material when the grinder has been turned off or is slowing down.
4) You can use steel to stop the wheel when it is slowing down.

Statements 1, 2, and 3 about grinder safety are true, while statement 4 is not true as it poses significant safety risks. Proper use of grinders requires adherence to safety practices to prevent accidents.

Explanation:

Analysis of Grinder Safety Statements

This question involves examining the safety guidelines surrounding the use of grinders. Let's evaluate the statements one by one.

Never use a grinder if its wheel is less than 1/2 its original diameter. This statement is generally true. Using a grinder with a wheel that has lost more than half its diameter compromises safety and effectiveness.
Never use a pedestal grinder if the wheel is not true. This statement is also true. A non-true wheel can cause vibrations and unsafe operation, potentially leading to accidents.
Never grind material when the grinder has been turned off or is slowing down. This statement is true. Grinding should only be done when the grinder is operating at the correct speed to ensure safe and effective material removal.
You can use steel to stop the wheel when it is slowing down. This statement is not true. Using steel or any object to stop the grinder's wheel can be extremely dangerous and is not a recommended practice, as it can result in injury or damage to the equipment.

In summary, statements 1, 2, and 3 are true, while statement 4 is not true and poses safety risks.

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