- #106
Ibix
Science Advisor
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No, but I know a guy who broke a very expensive mirror while trying to prevent a fly from landing on it.Twigg said:Any of y'all ever tried to chase a squirrel out of an optics lab?
No, but I know a guy who broke a very expensive mirror while trying to prevent a fly from landing on it.Twigg said:Any of y'all ever tried to chase a squirrel out of an optics lab?
During the Christmas break my Freshman year of college, I got the idea of making a loudspeaker that moves air molecules directly using electric fields. The idea was to ionize a region of air and operate on that with the electric fields. So I needed high voltage DC. I managed to conjure up a DC circuit but had to build my own 50,000 volt capacitor. So I made an oil capacitor using metal plates. It was crude but functional.Tom.G said:Well, if we can ignore the 'recently'.
Sort of a toss-up between these two.
1)
I was a teenager with a Model-T Ford Spark Coil (ignition coil). The interrupter (ignition points, on the primary side) was tightened down to remain closed and it was connected to a step-down transformer from a toy electric train. Could still draw a spark from the secondary. Somehow I ended up with my hands on opposite ends of the secondary (high voltage winding). Hand and arm muscles stayed contracted so I couldn't let go. Fortunately I was experimenting while sitting on the bed and used the remainder of my body to throw myself away from that alligator.
What was the problem with that guy? Wouldn't wear his safety glasses?Twigg said:Any of y'all ever tried to chase a squirrel out of an optics lab? It's a singularly humiliating experience.
A friend of a friend had partial sight loss from an accident with a high power laser. The dumb thing was having a beam path you could walk through.Twigg said:At least I wasn't using a YAG. The whole lab would've smelled like squirrel flambé.
I worked at one of the big laser companies for a long time. Everything we did was Class 4 stuff. I was always surprised at how cavalier the older laser guys were their laser beams. Many had stories of retina damage. The one I remember most was the story of a guy that saw red stuff coming out of the wall, that was the blood leaving his retina. The de facto rule for safety glasses in the R&D labs was often "you put them on when you think you are doing something really dangerous and you're not in a hurry". There were a couple of guys I didn't want to be in the room with; a couple of labs I didn't really want to go in unannounced. No warning lights, interlocks, etc. People would come and go into the labs when ever they wanted, nothing was locked up. On the manufacturing floor (open plan) the techs would often yell out "mode check" and put a concave mirror into the beam path of big ion lasers (1 - 30W) and shine it up on the wall far away.Ibix said:A friend of a friend had partial sight loss from an accident with a high power laser. The dumb thing was having a beam path you could walk through.
My friend had just joined the lab and was told he was volunteering to be laser safety officer. He was exactly the right man for the job - the kind of person who had no problem telling senior types that no they were not doing X any more.
You're right. There was no YAG (or any other high power laser) on the experiment I was talking about, and if there was the beam path would've been enclosed. I just mentioned a YAG as a joke.Ibix said:A friend of a friend had partial sight loss from an accident with a high power laser. The dumb thing was having a beam path you could walk through.
To be honest, I won't say I'm perfectly safe with low power beams (I don't mess around with high power or high levels of other risk), but man I didn't think that level of deviance existed...DaveE said:I was always surprised at how cavalier the older laser guys were their laser beams. Many had stories of retina damage.
That's just nutters. Sure, I've done procedures like that where I look at the mode far away from the table, but never with anything even logarithmically close to that level of power, I do it when there's low traffic, and I put up signage and I tell people ahead of time. I'm sorry you had to work with people who thought so little of their coworkers wellbeing.DaveE said:the techs would often yell out "mode check" and put a concave mirror into the beam path of big ion lasers (1 - 30W) and shine it up on the wall far away.
I feel like we could have a very long conversation about interlock designs haha Even some of the modern ones I've seen have left me seriously scratching my head. There's nothing worse than a safety feature that doesn't keep you safe AND is still annoying!DaveE said:There were some pretty close calls with bad designs.
I'm not sorry. It was more fun back then and I learned a lot. Much better than my previous job of ultra hi-rel power supply design. I did one design that took a 6-12 months to do and then I spent most of the next year analyzing it to prove it met all of the Mil-Specs for it's intended use; then I quit. We weren't allowed to use any "new" devices, they didn't have proven reliability (ugh!). In their defense, that was the sort of thing where you don't get any second chances, it HAD TO be right.Twigg said:I'm sorry you had to work with people who thought so little of their coworkers wellbeing.
I was taking pictures one Sunday morning on a rocky beach in Maine. I came across a lens case, with "Canon" printed on it, just sitting there in the middle of the rocks. It proved to be a new and very expensive lens. Just then, I saw a car enter the parking lot at high speed, skidding to a stop. A young woman jumped out and ran across the beach. She took the lens and case out of my hands, "oh thank you thank you THANK YOU so much..." Then she ran off towards the car, saying "I'm late for the wedding." Finally burning rubber leaving the parking lot. It was all over so fast, I wondered if I imagined the whole thing.DennisN said:camera lenses
I've only got quite affordable lenses, many vintage lenses (except the kit zoom lens and two other, I think). One advantage besides being affordable is that I wouldn't be very upset if I damaged or lost one. The only thing I would mind damaging or losing is the camera.gmax137 said:new and very expensive lens
Ken Rockwell said:Pricing. You don't want to read this part. This was Nikon's most expensive of all its expensive lenses. [...]
Besides my kit at work ( which is actually works) my portable personal tech kit is quite old and make do. My device for pf for eg is a Hudl, it's old and does not charge so well. I decided to spoil myself and bought a brand spanking new charger, £9 no less.DennisN said:I've only got quite affordable lenses, many vintage lenses (except the kit zoom lens and two other, I think). One advantage besides being affordable is that I wouldn't be very upset if I damaged or lost one. The only thing I would mind damaging or losing is the camera.
High-end lenses can be RIDICULOUSLY expensive.
When I bought my mirrorless Sony camera, I remember finding a small note inside the box which offered some discount when buying a new Sony lens. That made me a bit excited, and I went to the Sony page to look at the lenses. The prices were ridiculous, many or most of them were more expensive than the camera. So, no new Sony lens for me.
When you said ridiculously expensive you were NOT kidding!DennisN said:I've only got quite affordable lenses, many vintage lenses (except the kit zoom lens and two other, I think). One advantage besides being affordable is that I wouldn't be very upset if I damaged or lost one. The only thing I would mind damaging or losing is the camera.
High-end lenses can be RIDICULOUSLY expensive.
When I bought my mirrorless Sony camera, I remember finding a small note inside the box which offered some discount when buying a new Sony lens. That made me a bit excited, and I went to the Sony page to look at the lenses. The prices were ridiculous, many or most of them were more expensive than the camera. So, no new Sony lens for me.
Edit: By the way, here is a RIDICULOUSLY expensive vintage lens, the Nikkor 13mm f/5.6, the "holy grail" of lenses. Pricing info here (at KenRockwell.com).
This reminded me of the time I manually disconnected the cable from the spark plug of a lawnmover, while it was running, because it wouldn't stop. It felt like I got hit with a sledgehammer. I flew backwards onto the driveway pavement.Tom.G said:I was a teenager with a Model-T Ford Spark Coil (ignition coil). The interrupter (ignition points, on the primary side) was tightened down to remain closed and it was connected to a step-down transformer from a toy electric train. Could still draw a spark from the secondary. Somehow I ended up with my hands on opposite ends of the secondary (high voltage winding). Hand and arm muscles stayed contracted so I couldn't let go. Fortunately I was experimenting while sitting on the bed and used the remainder of my body to throw myself away from that alligator.
Nowadays you could have a youtube channel.Astronuc said:historical
BillTre said:Its always good to know the best way to break into your house:
- climb in a second story window
- punch out a window so you can unlock door
- ...