View Full Version : List of peculiar fabrication tricks
Jac@stafford.net
30-Sep-2016, 09:27
Sometimes a surprise dawns on this old brain. Maybe we can build on these tiny, but useful tips. This one worked for me yesterday.
Yeah, we have plenty of 1/4" male to 3/8" male adapters, but to convert a tripod mount from male 1/4" to female 3/8" ? Or 3/8" male to 1/4" female?
A coupling nut can do it. Visit your Ace Hardware fasteners section. Look for the drawer of nut extensions, AKA coupling nuts. In one bin is an extended nut with 1/4"x24 female on one end, 3/8"x16 female on the other.
155682
Steve Goldstein
30-Sep-2016, 10:59
I think the person who did the drawing doesn't know much about mechanical stuff. It looks to me like the 3/8-16 threads are left-handed!
Tin Can
30-Sep-2016, 11:52
When redoing plumbing for the darkroom, use sawzall to cut out old pipe.
Saves a lot of time and aggravation.
Jac@stafford.net
30-Sep-2016, 12:01
I think the person who did the drawing doesn't know much about mechanical stuff. It looks to me like the 3/8-16 threads are left-handed!
Told you it was peculiar! Good eye!
Oi! And to think that illustration is used so widely!
Jac@stafford.net
30-Sep-2016, 12:04
When redoing plumbing for the darkroom, use sawzall to cut out old pipe.
Det Cord is more fun, and it's great for unclogging drains.
Jerry Bodine
30-Sep-2016, 14:50
...In one bin is an extended nut with 1/4"x24 female on one end, 3/8"x16 female on the other.
I'm sure you meant 1/4"x20, not 1/4"x24; just a nit.
Jerry Bodine
30-Sep-2016, 14:57
I think the person who did the drawing doesn't know much about mechanical stuff. It looks to me like the 3/8-16 threads are left-handed!
The workers in the pipe manufacturing plant where my dad was superintendent used to send rookies to fetch a left-handed monkey wrench, just for amusement.
Tin Can
30-Sep-2016, 15:25
If you need one pipe fitting you need 2.
I used to send workers for pipe to our tool crib which had more inventory than Home Depot. During training I told them get 2 or 3 of anything as a trip to the crib in our million sq ft factory could take an hour, if the line was short.
But ingrained parsimony is hard to overcome. The worker would bring one piece occasionally, I would grab it and immediately declare it useless. I usually quietly told them, 'Go get 2 more and inspect them first! While you are walking.'
We had a 5 year problem with a bean counter that brought in a new supplier, who filled our bins with off shore crap. Bolts were snapping, pipe castings leaking, orders were to use the stuff up.
Finally somebody got permanent disability from a machine that failed from fake Grade 8 bolts.
McMaster Carr was quietly brought back, the stock was replaced and for years we were still finding those naughty bit's
Jim Jones
1-Oct-2016, 05:46
The workers in the pipe manufacturing plant where my dad was superintendent used to send rookies to fetch a left-handed monkey wrench, just for amusement.
I've thought of converting a monkey wrench to left-handed just as a conversation piece. It's been done in fiction if not in real life by Richard McKenna of Sand Pebbles fame. There was a time when creative people worked hard at being pranksters instead of merely repeating old tricks.
Preventing oxidation/corrosion on aluminum by very carefully cleaning it after finishing the bare metal, then while wet, dripping nitric acid into overlapping circles on the surface, then rewashing... This changes the bluish/blackish oxides to a natural clear whiteish oxide, and the surface then becomes the analog of stainless steel protective oxides, and stays looking like it was finished, for many years to come... I still have some parts that were treated treated this way 25ish years ago, and they still look like they were cut yesterday!!! (I learned this from a old technical book "Metal Seaplane Construction", and this was the process for corrosion proofing...)
I'd still be using this, but my local source for nitric acid (Tri-Ess Sciences) is now long gone... :-(
Steve K
Jac@stafford.net
1-Oct-2016, 08:07
If you have something made of wood and glued together, such as an early view camera back, just pop it into a microwave on high for 30 seconds and it will easily pull apart at the glued area. (Works with animal glue. Don't know about Gorilla glue which sucks in so many ways anyway.)
Remove screws and ground glass first, of course!
Jerry Bodine
1-Oct-2016, 09:42
If you have a building that you want to protect from corrosion, you can do what my long-time employer did when they had a new building constructed: leave the exposed steel girders and support structure UNfinished. The corrosion (rust) would progress only so deep into the metal, then stop, and that rust layer would act as a protection from the weather. That layer, of course, was considered a sacrificial layer by the designers who had to insure that the remaining good metal was structurally adequate. But this process, coupled with the very dark windows, did produce one ugly building. Certainly testing had to be done to determine how deep the sacrificial layer would be.
I like to rub the threads of an eye screw on a bar of soap before screwing it into a drilled hole in a photo frame (for attaching the hanging wire). This allows me to hand-tighten the eye screw -- I have snapped a few screws using a tool to turn them.
I almost wrote "...before screwing it into a pre-drilled hole...". but I could not figure out what a pre-drilled hole would look like.
Kirk Gittings
1-Oct-2016, 10:38
The workers in the pipe manufacturing plant where my dad was superintendent used to send rookies to fetch a left-handed monkey wrench, just for amusement.
I worked sawmills (also did logging) as a grunt after graduating college. I liked working with my hands, wanted to live in the woods/mountains and wasn't ready for "real" life yet. So in my first week they sent me to look for a "lumber stretcher" :)
barnacle
1-Oct-2016, 10:59
Heh. In the broadcasting industry, we'd give the newbies one end of a piece of cable and ask them to hang on to it so we could measure a run. Round the first corner, tie it to a doorknob...
Neil
I think the person who did the drawing doesn't know much about mechanical stuff. It looks to me like the 3/8-16 threads are left-handed!
I think that it's the other way round - you don't know much about mechanical stuff. There are coupling nuts with left handed threads!
Sometimes a surprise dawns on this old brain. Maybe we can build on these tiny, but useful tips. This one worked for me yesterday.
Yeah, we have plenty of 1/4" male to 3/8" male adapters, but to convert a tripod mount from male 1/4" to female 3/8" ? Or 3/8" male to 1/4" female?
A coupling nut can do it. Visit your Ace Hardware fasteners section. Look for the drawer of nut extensions, AKA coupling nuts. In one bin is an extended nut with 1/4"x24 female on one end, 3/8"x16 female on the other.
155682
It's not a good idea when you realize that the coupling nut reduces the stability of whatever you screw in it.
Jac@stafford.net
2-Oct-2016, 06:48
It's not a good idea when you realize that the coupling nut reduces the stability of whatever you screw in it.
Of course prudence is important. Test! In my application it was certainly stable.
Test, try, decide or not.
A tip: chuck the coupling nut in a drill press and finesse the very ends to be flat. It takes only a couple touches to make it so.
Jac@stafford.net
2-Oct-2016, 06:50
I think that it's the other way round - you don't know much about mechanical stuff. There are coupling nuts with left handed threads!
Would find us a source? I had no such luck.
.
Jac@stafford.net
2-Oct-2016, 06:53
I almost wrote "...before screwing it into a pre-drilled hole...". but I could not figure out what a pre-drilled hole would look like.
Vaughn, I'm surprised. Humboldt County is famous for it's hole cottage industry. My brother sent me a whole hole set. Bummer they weren't numbered and lettered. Anyway, they are impossible to keep in a pocket.
Would find us a source? I had no such luck.
.
http://www.spaenaur.com/pdf/sectionC/C5.pdf
For the rest - google "left handed coupling nuts" and enjoy reading.
Similar usage as https://en.m.wikipedia.org/wiki/Turnbuckle
Would find us a source? I had no such luck.
.
Of course prudence is important. Test! In my application it was certainly stable.
Test, try, decide or not.
A tip: chuck the coupling nut in a drill press and finesse the very ends to be flat. It takes only a couple touches to make it so.
Sure, it only takes a couple of touches and the two rods, screwed to the coupling nut don't touch each other and the assembly happens to wackle. No amount of test protects you again it.
Similar usage as https://en.m.wikipedia.org/wiki/Turnbuckle
Well, speaking the wikipedia, it's enough to read 3 lines - https://en.wikipedia.org/wiki/Coupling_nut
Well, speaking the wikipedia, it's enough to read 3 lines - https://en.wikipedia.org/wiki/Coupling_nut
Why read when an image is quicker?
Why read when an image is quicker?
A good question. But some of us are, well, quite stubborn...
Jac@stafford.net
2-Oct-2016, 07:52
Sure, it only takes a couple of touches and the two rods, screwed to the coupling nut don't touch each other and the assembly happens to wackle. No amount of test protects you again it.
They need not touch each other. Forget the impressionism. Try it!
They need not touch each other. Forget the impressionism. Try it!
In such a case the thread tolerances add one to the other and the wackling results. Don't forget the science. And yes, some people took good pictures with a camera laid on a big stone!
Jac@stafford.net
2-Oct-2016, 14:05
In such a case the thread tolerances add one to the other and the wackling results. Don't forget the science.
I do not forget the science; I encourage those who look only at paper specs and imagine how simple mechanics might work to get down and make something! They might be pleasantly surprised, and if they are not handy they can always return to the monitor and make smart-ass remarks like yours instead of living life.
.
It looks to me like the 3/8-16 threads are left-handed!
That's one common version of a length adjuster.
If both sides have the same-handed thread, then any change is only due to different thread pitches.
If both sides have the same pitch, then moving the adjuster does not change the shaft spacing at all.
If the two ends have different hands, then turning one way will increase shaft spacing, the other way will reduce it.
This is true regardless of the thread pitches involved.
Here are simple left-hand to right-hand couplers on McMaster-Carr catalog page 3295
http://www.mcmaster.com/#hex-coupling-nuts/=14fcoep
If the link expired, go to www.mcmaster.com and enter 3295 in the search box at upper left.
- Leigh
I do not forget the science; I encourage those who look only at paper specs and imagine how simple mechanics might work to get down and make something! They might be pleasantly surprised, and if they are not handy they can always return to the monitor and make smart-ass remarks like yours instead of living life.
.
What a smart-ass remark, full of science and real life! For someone who a few hours ago didn't even know that left handed thread coupling nuts could be seen in the world you're surely impressive. In its own way.
Jac@stafford.net
2-Oct-2016, 14:37
What a smart-ass remark, full of science and real life! For someone who a few hours ago didn't even know that left handed thread coupling nuts could be seen in the world you're surely impressive. In its own way.
Show us your handiwork, please.
It is easy to sit at a computer monitor with Google and an engineering book, but sifting out real application is something one has to do. Do! You get it? I'm retired but a major effort of my employer was fabricating and testing composite materials, among other materials. There are a lot of surprises that occur regardless of the maths, and therein are the profitable outcomes.
.
Nathan Smith
25-Oct-2016, 10:27
I believe the way it works is that one side is right-handed, the other is left-handed, so turning the nut in one direction tightens (or loosens) both sides at once.
winterclock
25-Oct-2016, 16:03
This reads like two MEs sniping at each other over the cube sides. As the assembler waiting for them, if the parts weren't face to face to tighten against each other I would spin on a jam nut to keep things stable. Coupling nuts are often used to join two pieces of all thread, it's safer to add jam nuts than rely on contact between the rods. On my camera gear at least I have no threaded parts that will not go face to face; nothing extra is needed.
Jac@stafford.net
25-Oct-2016, 16:10
So obscure. Illustrations would be welcome.
Tin Can
25-Oct-2016, 16:40
First read of that post was confusing. Enginnere are always cursed by field personnel as idiots.
Field work, works...
So obscure. Illustrations would be welcome.
Mark Sampson
25-Oct-2016, 19:09
"In theory, theory and practice are the same; in practice, they are not."
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