[Tristan Lall]

Here are some related threads from deep in the archives (not all are entirely about machining):

team emergencies
First Injuries
Grady personal injury avoidance tip #2
Injuries
were there robot related injuries on your team?
pic: When Waterjets Get Nasty
pic: Waterjet nastiness Dermilogical Effects -face
FIRST Injuries
Serious Safety Incident - Please read to your teams

Originally Posted by Al Skierkiewicz

It went flying overhead where my head and upper body had been. I am alive today because I can't hold onto things.

In grade 7 or 8 shop class, someone* nearly did the same to me. He was using a drill press with a fixed cable or chain tied to the chuck key, presumably so as not to lose it—that's an idiotic convenience feature, by the way—and managed to forget the key in the chuck. Upon starting the drill press, it of course got tangled, then broke off and went flying at the spot where I'd been kneeling to pick something up a few seconds before.

Fortunately, an average drill chuck key can't do as much damage as an average lathe chuck key, so I would have been in rather less danger. He didn't fail; the embarrassment was probably sufficient to cement the lesson.

Originally Posted by Revant54

I remember about 3 years ago(I was a Freshman at the time), and I was drilling into a piece of diamond plate. Being a Freshman at the time, and not to bright in the machining sense; I didn't use anything to lock the plate down. To add to this initial dilemma, I unknowingly was drilling a bit too hard into the plate, and ultimately the plate got stuck in the bit, causing the plate to spin with the bit, resulting in my hands getting badly cut.

I've done something close to this—as a high school student working rather late one evening to finish off a robot. In my case, all that resulted were a few little scratches and bruises, rather than cuts. It had a lot to do with not realizing that a drill bit (especially a dull one) would catch on to the rough edge at the bottom of a hole in an aluminum plate. This caused it to lift up when I finished drilling the hole out to its finished size. So of course, the 4 in × 8 in × 0.25 in gearbox plate that I'd been working so hard to finish got picked up by the drill bit, unbalancing it; that wobbled around at a few hundred revolutions per minute for a second or so (hence the shallow and essentially bloodless scrapes on my hands), and then sheared the drill bit off, sending the plate glancing off my chest and into a pile of detritus underneath another piece of machinery. I was in no way seriously injured. Despite that fact, that's not a mistake I aim to make again.

Originally Posted by Kevin Sevcik

And keep your hand on the chuck key whenever it's in the chuck. If you never let it go till it's out of the chuck, it's stupendously less likely to take flight.

Originally Posted by Hawiian Cadder

a few years ago someone was using the mill and the wrench up there, the mill spin it up to 2400 rpm and then it shot off the top, nobody was hurt but it traveled about 100 feet across the shop

Speaking of mistakes I don't aim to make again, avoid leaving the wrench on the drawbar nut of a Bridgeport 2J2 knee mill. No injuries that time, because fortunately the spindle could only advance a half-turn before the wrench hit the motor housing and unseated itself loudly, falling straight to the ground. Like a lathe chuck key, thats a piece of equipment that should not leave your hand while engaged in a moving part, and which deserves to have a well-defined place in your line of sight when you're reaching for the power switch. (This milling machine—like most—was not set up that way: the wrench lived on the right-hand side of the machine, behind the quill lever and partially obscured by the digital readout, while the power switch was located on the upper left of the mill head.)

*He has a ChiefDelphi account, although he didn't at the time.