Will I be permitted to pack a cheese grater in my carry-on bag for a domestic U.S. flight, or will this be considered a "potential weapon" and prohibited?
It probably depends on how your cheese grater is constructed. You can see the official list of prohibited items on the TSA web site. The most relevant section seems to be the "sharp objects" section, which lists:
- Box Cutters
- Ice Axes/Ice Picks
- Knives - except for plastic or round bladed butter knives
- Meat Cleavers
- Razor-Type blades - such as box cutters, utility knives, and safety razor blades (disposable razors and their cartridges are permitted)
- Scissors - metal with pointed tips and blades shorter than four inches
- Swords - cutting or thrusting weapons, including fencing foils
However, others likely would be considered 'sharp objects'.
It also almost certainly depends on the judgement and mood of the person on duty who checks your bag.
I was once forbidden to take marshmallow cream in my carry-on, because it was "liquid." (Try pouring marshmallow cream, and then tell me its a liquid!)
According to the TSA's "Can I Bring..." web site (also available on their Mobile App) you CAN bring your Cheese Grater in either Carry-on or checked-in luggage.
Search Results For: cheese grater
Check or Carry-on
You may transport this item in carry-on baggage or in checked baggage. For items you wish to carry-on, you should check with the airline to ensure that the item will fit in the overhead bin or underneath the seat of the airplane. Please be sure to wrap cords tightly around electronics items and pack your bag in neat layers (layer of clothes, layer of electronics, layer of clothes, layer of shoes, etc.) to help officers get a clear look at your bag.
Even if an item is generally permitted, it may be subject to additional screening or not allowed through the checkpoint if it triggers an alarm during the screening process, appears to have been tampered with, or poses other security concerns. The final decision rests with TSA on whether to allow any items on the plane.
This is potentially one of those situations where it would be worth carrying a print-out of that page showing that it's OK, just in case the TSA agents decided that it was not allowed.