This is a good idea always, but is listed in the NJ regional rules…
3- Don’t forget the new rules this year. Everyone in the pit must wear safety glasses, so you must bring enough for your team. It would also be wise to bring extras for your fans. Anyone lifting/uncrating the robot must wear gloves. Please make sure you have these items with you at the competition.
The biggest reasons is that gloves can get caught in something, such as a drill bit, grinder, or saw blade. In the best situation, it will just pull the glove off your hand and tear it to shreds. In the worst it will pull your hand into the machine and you’ll come away with a couple less fingers.
For example, there was an episode of American Chopper a couple years ago where Rick was wearing gloves while using a drill press. The edge of his glove got snagged in the bit, and it pulled his hand into the drill, causing a significant gash to the side of his hand. He had to goto the hospital to get the injury stitched shut. Luckily, he was okay.
I would like to point out the “remove jewelry” in Sean’s post above. This also includes rings on your fingers not just dangling jewelry.
WARNING: THIS STORY MIGHT GROSE SOME PEOPLE OUT! DON’T READ IF YOU ARE SQUIMISH!
Here is a personal example: When I was in high school I worked for a flight school at a small local airport as the shop helper kid. It was a dream high school job because I loved airplanes. One day one of the A&P mechanics was working on the engine of a helicopter in the hanger and was just standing on one of those little flip out foot rests halfway up the side of the fuselage. His foot slipped and he went sliding down the side of the helicopter which wasn’t a large drop but his wedding ring got stuck on something (a screw or rivet or something) and due to the falling weight of his body caused the skin on his ring finger to be pealed off sort of like a sock. That left an impression on me.
The reasoning for no gloves while using power tools (or anything that spins really) is simple. Gloves are stronger than human skin. If your finger hits a grinding wheel for example, the worst that will probably happen is you lose a little chunk of skin. If you are wearing a glove and hit the grinding wheel, you could break and or/lose fingers quite easily. I did an experiment once on a large disc sander (16" or so). There was approximately 3/8" gap between the wheel and the table. The sander had been turned off for about 3 minutes. It was still spinning down. It had good bearings and a large flywheel effect. Anyhow, I took a shoe, and stuck it right up against the wheel (bare steel wheel, not even any sanding disc). It sucked the whole shoe about half way in, into this 3/8" wide gap faster than I could blink. I mean, think about how thick a shoe is. And there wasn’t even a motor powering this thing at the time. This machine is capable of taking a whole hand without a doubt. And this machine is not too different than something many teams probably use. So, don’t wear gloves while grinding (yes, it gets hot, yes, that’s what water is for), sanding, drilling, working on sprockets and chains or gears, etc.