make shrink-on sleeve

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Gwhite
Posts: 372
Joined: Tue Jul 11, 2017 3:38 pm

Re: make shrink-on sleeve

Post by Gwhite » Sat Jan 29, 2022 2:16 am

I hadn't heard of OnShape. It must be very special, considering the price. If I ever lose my free education Fusion360 license, I can switch to a free "experimenter" license. The one thing that concerns me about Fusion is the whole cloud thing. I really need to go through all my designs & at least save STP file copies locally.

"Doc" Edgerton was mostly retired when I was a Teaching Assistant. They had a lecturer who talk the courses, but if he wasn't traveling, Doc hung out in his office most days. He was helping chase the Loch Ness Monster back then, and occasionally working with Cousteau. He was a really nice guy, and extremely practical & down to earth. I grew up in Los Alamos, New Mexico, and he gave a lecture at the Laboratory there a few years after I had gone on to tach other courses. Doc and his wife made a point of tracking down my Mom and taking her out to dinner. My mother remembered attending one of his touring lectures at her college in the late 1930's. She was absolutely tickled pink & a bit star-struck almost 50 years later.

We did most of our high speed photography with 35 mm black & white. Doc's approach to drying negatives was to fold a paper towel over the film, and then pull the negatives through the towel. He said he'd never observed any scratches from the process over 40 years of doing it. I could always spot the students that had taken Minor White's photography class by the way they winced when we did that.

We spent a lot of time teaching basics of flash photography, but also used repeating strobes to view repetitive motion by eye. One of the popular labs was taking photos of .22 bullets in flight, cutting playing cards in half & such. The fun part was that the students had to do a final project of some sort, usually in groups of 2 or three. Lots of them came up with interesting objects to shoot with the .22. There were safety rules about nothing that could shatter or deflect the bullets, and if you shot fruit, you had to make a "fruit trap" to contain the shrapnel.

There is a famous photo Edgeton took of shooting an apple with a .30 caliber military rifle:

Image

What they don't mention is that a few milliseconds after the photo was taken, the entire lab was filled with flying apple sauce. 30 years later, I could still smell a hint of apple in the lab on a hot humid day. Hence the requirement for a fruit trap...

jferguson
Posts: 247
Joined: Mon Mar 30, 2015 7:26 pm
Location: St Petersburg, FL

Re: make shrink-on sleeve

Post by jferguson » Sat Jan 29, 2022 4:56 am

One might ask about the photo of the shot that liberated the casing the apple in your photo is impaled on. I have to think about drying film by threading it through a towel. I have to confess I'm with the guys who were twitchy about this.

i vaguely remember a story about Edgerton's involvement with the search for the nuke which sank in the Atlantic vicinity of Azores. I may have this sinking mixed up with another. I suspect the details are still classified.

Gwhite
Posts: 372
Joined: Tue Jul 11, 2017 3:38 pm

Re: make shrink-on sleeve

Post by Gwhite » Sat Jan 29, 2022 4:04 pm

Through working with Cousteau on underwater cameras, Doc got heavily involved in the development & use of side-scan sonar, which would have been the tool of choice for such a search. He also had a long history of working with the US military & nuclear stuff from WWII. The walls of his office had at least half dozen black & white photographs of early nuclear bomb tests. A lot of the super fast cameras he developed were for that work. Even at 10 million frames a second, you have plenty of light, and we still had reels of ASA 6 film left over. I used some of it on my final project when I took the high speed photography class as an undergrad.

https://interestingengineering.com/film ... ing-marvel

jferguson
Posts: 247
Joined: Mon Mar 30, 2015 7:26 pm
Location: St Petersburg, FL

Re: make shrink-on sleeve

Post by jferguson » Sat Jan 29, 2022 5:34 pm

Wow ASA6. i think Kodachrome used to be ASA10 in the '50s when I started photography. We were delighted when it went to ASA25.

re fast cameras: My Dad worked for a company which made, among other things, high-voltage fuses for the Utilities. in late '50s GE published a paper which suggested that fuses did not provide the protection that circuit breakers did and in fact permitted a brief episode of what they called single-phasing which was not good. It was nonsense, but in pursuit of better understanding of fuse behavior, he and his colleagues rented a high speed camera. I think it worked by moving the film in an arc at the focal point and moving the image with a motor-driven rotating prism (not at all sure about this in any case).

They did a bunch of tests, became skilled with the camera, and then looked at the results with a projector whose speed was variable and could be set to advance a frame at a time at whatever frame/second you wanted. To the astonishment of the engineers involved there was a periodic wave in the exhaust ejected from the fuse - a 1 3/8 diameter tube about a foot long which I think was made out of some kind of phenolic - they were reddish brown.

Slide rules were deployed and the period of the pulses in the exhaust was calculated which they soon discovered to be a harmonic of 60 Hz (well CPS at the time). There was a discussion about who would write the paper about this truly momentous discovery for submittal to one of the AIEE committees. The writing was underway when one of the doubters had another look at the projector. It turned out that it clicked 3 times with each frame.

BTW, what years were you at MIT?

Gwhite
Posts: 372
Joined: Tue Jul 11, 2017 3:38 pm

Re: make shrink-on sleeve

Post by Gwhite » Sat Jan 29, 2022 6:37 pm

That camera sounds like one I used for my class project. Film just can't be moved super fast before it tears & disintegrates, so the solution was to hold the film in a fixed arc, and move the image with the rotating mirror. You still needed a fast "shutter", which was taken care of by using a strobe. Getting the timing right was a bit tricky, but it all worked OK.

I was at MIT from the Fall of 1970 though the summer of 1978. I bailed on the PhD program when I realized several of my fellow teaching assistants had been in grad school for 10 or more years. I decided industry looked like more fun (and paid much better) & went to work at Hewlett Packard in silicon valley.

jferguson
Posts: 247
Joined: Mon Mar 30, 2015 7:26 pm
Location: St Petersburg, FL

Re: make shrink-on sleeve

Post by jferguson » Sat Jan 29, 2022 8:00 pm

my cohort (not including me) would have been 1960-70 including grad school. One of them was very fond of Edgerton and had worked(?) in his lab - the wet one.

back to printing next post.

Phil
Posts: 214
Joined: Mon Sep 19, 2016 7:49 pm

Re: make shrink-on sleeve

Post by Phil » Wed Feb 02, 2022 9:09 pm

I paint, then laser etch the switch covers. I tried to print the lettering, but even with a 0.25mm nozzle, it just is not that great. It can also take a few trials and errors to get it all right, hence the pile. Fortunately, the local Innovation Studio has four laser cutters. At first I tried to cut the plastic, then paint inside the removed part. As you said earlier, too many small voids that the paint would fill and make a mess. I recently printed some in Glow-in-the-Dark PLA and painted them, but I have not etched the lettering, yet, even though PLA is not ideal for the environment.
I wanted to use nylon for the toughness and heat resistance, but someone on this forum suggested using an acetone-based paint on ABS. That does really well, and I think the paint actually strengthens the covers.

The silencers do erode, but plastic ones actually deaden the sound better than metal. I have been experimenting with BASF and TVF filaments, too.
BTW, there is an Edgerton museum/learning center in his hometown, Aurora, Nebraska. https://edgerton.org/
Attachments
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Phil
Posts: 214
Joined: Mon Sep 19, 2016 7:49 pm

Re: make shrink-on sleeve

Post by Phil » Wed Feb 02, 2022 9:10 pm

jferguson wrote:
Sat Jan 29, 2022 4:56 am
One might ask about the photo of the shot that liberated the casing the apple in your photo is impaled on.
What makes you think it is an empty?

jferguson
Posts: 247
Joined: Mon Mar 30, 2015 7:26 pm
Location: St Petersburg, FL

Re: make shrink-on sleeve

Post by jferguson » Sat Feb 05, 2022 4:53 pm

A live round might have generated a photo which would have been hard to analyze - in the event of an aiming anomaly 8-)
Did you ever try the plastic coke-bottle silencer scheme which was "available" for IIRC the MAC 10 ?

Phil
Posts: 214
Joined: Mon Sep 19, 2016 7:49 pm

Re: make shrink-on sleeve

Post by Phil » Sat Feb 05, 2022 5:17 pm

jferguson wrote:
Sat Feb 05, 2022 4:53 pm
Did you ever try the plastic coke-bottle silencer scheme which was "available" for IIRC the MAC 10 ?
That is Hollywood. The Poor Man's James Bond used bottle caps inside a pipe, (which would work, a little bit); Bourne, (I think), used a 2-liter, (BS). Another internet meme is the oil filter. I remember an even funnier one: I think I saw it on the TV series Shaft. He used a potato. A big pillow would actually work, but it would be tough to see around and might start on fire.

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