Anybody have any machining based magic tricks?

dgfoster · Jan 25, 2015

My wife and I have been invited to an evening with a group of 50 or so friends. This is an annual "magic show." The expectations are not for a slick presentation or "sawing a lady in half" tricks. But folks do present card tricks, curious mechanical tricks and the like. I thought it might be fun to try to put together something in the shop and present it to the group. I am looking more along the line of sleight of hand rather than an object that is static but seems to defy reason---like nested balls or the like.

So, the amount of time I would be willing to put into this might be a couple of hours on a manual mill and lathe. Any thoughts? I suppose if it was really really "cool," the time budget coudl be increased a bit. That last statement sounds dangerous....

Denis

oldbikerdude37 · Jan 25, 2015

One trick I know that is worth its weight in gold is changing a universal joint with a bench, open vice and a hammer in about 40 seconds.

I see people use vices as a press and other things and foul it all up. Bang bang bang clip clip done.

Bill D · Jan 25, 2015

You make a ball and a ring that are close in diameter but not quite allowing the ball to go inside the ring. heat the ring with a propane torch and it goes over the ball. A bimetal strip bends nicely with heat. Maybe pull one from a thermostat.

The British empire hired a magician to impress the locals with British magic. I think in India or Arab colonies around 1880. he had electro magnets in a table and invited local strong men to lift iron weights off the table. They could not do then he turned off the power and showed them the strength of British power.
Bil lD.

lazz · Jan 25, 2015

I have always thought Lenz's law was as close to magic as it gets.
https://www.youtube.com/watch?v=RU5RVQotz-o shows it with aluminum bar stock and angle not just copper pipe.

dgfoster · Jan 25, 2015

oldbikerdude37 said:
One trick I know that is worth its weight in gold is changing a universal joint with a bench, open vice and a hammer in about 40 seconds.

I see people use vices as a press and other things and foul it all up. Bang bang bang clip clip done.

Care to post a video of that? I think this crowd would enjoy that bit of magic. Not kidding.

Bill D said:
You make a ball and a ring that are close in diameter but not quite allowing the ball to go inside the ring. heat the ring with a propane torch and it goes over the ball. A bimetal strip bends nicely with heat. Maybe pull one from a thermostat.

The British empire hired a magician to impress the locals with British magic. I think in India or Arab colonies around 1880. he had electro magnets in a table and invited local strong men to lift iron weights off the table. They could not do then he turned off the power and showed them the strength of British power.
Bil lD.

Interesting bit of history trivia. I can only imagine the guffaws and drinks that went all around after the delegation of locals left. But then, what goes around comes around as demonstrated by history in India and other places.

lazz said:
I have always thought Lenz's law was as close to magic as it gets.
https://www.youtube.com/watch?v=RU5RVQotz-o shows it with aluminum bar stock and angle not just copper pipe.

That is a very good candidate. I like the idea of using this setup to demonstrate Lenz' law which only a few in the crowd will be aware of. Another good feature is the shop time required is close to zero and I have some suitable aluminum scraps stting around. The demo of dropping the magnet down a conductive tube is also very impressive. But for a large group the inclined flat bar will show better. Thanks.

[Added a few minutes latter: The current induced in the inclined bar has to dissipate through induction of heat. If I can get my hands on one of those super sensitive IR scopes I could demonstrate heat streaks down the copper bar---one more level of cool. But then again, maybe I am the only one who would think so.

]

In addition, for practical use, capitolizing on this principle to damp motion like that in a pendulum is worth considering.

Denis

James Lederer · Jan 25, 2015

A copper water pipe and cylindrical neodymium magnet works well. You can hold it in your hand and carry it around to small groups. If the pipe is three or four feet long it'll take maybe 6 or 8 seconds to fall through, and if you look in the end of the pipe you will see the magnet floating down the middle.

Halcohead · Jan 26, 2015

I've always liked boxes where there's no apparent lock, but they don't open until put into a specific orientation. Might be too much time to make though.

A large flywheel in a briefcase is always fun. It behaves normally when picked up, until the person carrying it tries to turn.

dgfoster said:
[Added a few minutes latter: The current induced in the inclined bar has to dissipate through induction of heat. If I can get my hands on one of those super sensitive IR scopes I could demonstrate heat streaks down the copper bar---one more level of cool. But then again, maybe I am the only one who would think so. ]

In addition, for practical use, capitolizing on this principle to damp motion like that in a pendulum is worth considering.

Denis

I haven't run the numbers but intuition says heat generated will be basically undetectable. If you want to run the numbers it's the released gravitational potential energy distributed over the mass of tube through which the magnet fell. Temp rise can be calculated from the specific heat of the tube.

You can also make cuts in the tube to affect the speed of the magnet. Axial cuts will break up the current loops, reducing the effect. There's an old physics demo of dropping a pendulum through the gap in a powerful horseshoe magnet. Affixing a metal plate to the pendulum makes it stop as soon as the plate meets the magnetic field, but slitting up the plate reduces the effect.

dgfoster · Jan 26, 2015

Halcohead said:
<>

I haven't run the numbers but intuition says heat generated will be basically undetectable. If you want to run the numbers it's the released gravitational potential energy distributed over the mass of tube through which the magnet fell. Temp rise can be calculated from the specific heat of the tube.

You can also make cuts in the tube to affect the speed of the magnet. Axial cuts will break up the current loops, reducing the effect. There's an old physics demo of dropping a pendulum through the gap in a powerful horseshoe magnet. Affixing a metal plate to the pendulum makes it stop as soon as the plate meets the magnetic field, but slitting up the plate reduces the effect.

I agree that the heat generated is very small. But I suspect that a FLIR scope could see a streak generated on the inclined aluminum sheet demo in the video linked above. I once saw a demo in which a person simply walked barefoot across a wood floor at a normal pace. Using the scope their heat footprints were clearly visible for a minute or two----and that was using a fairly old scope. I would guess that newer scopes with their adjustable gain and color rendering would detect it. If it did, that is what would be cool---the "undectable" suddenly is detectable.

I had not thought of the various cuts that would affect the eddy current generation efficiency. I will include that.

I liie your box idea too. But you are right, that probably would be too much work.

Still looking for more ideas. If can come up with other ideas I won't bbe a "one trick pony."

Denis

bhigdog · Jan 26, 2015

I can make my money disappear....................Bob

Philabuster · Jan 26, 2015

James Lederer said:
A copper water pipe and cylindrical neodymium magnet works well. You can hold it in your hand and carry it around to small groups. If the pipe is three or four feet long it'll take maybe 6 or 8 seconds to fall through, and if you look in the end of the pipe you will see the magnet floating down the middle.

Another thing to expand on the copper pipe trick is to get a second copper pipe and slide it over the first pipe. Say 1/2" pipe and 3/4" pipe. Have the person time how long it takes for the magnet to drop through the first pipe, then slide on the second pipe and re-run the experiment. The second pipe slows the magnet's descent significantly.

cg285 · Jan 26, 2015

oldbikerdude37 said:
One trick I know that is worth its weight in gold is changing a universal joint with a bench, open vice and a hammer in about 40 seconds.

I see people use vices as a press and other things and foul it all up. Bang bang bang clip clip done.

there is another way besides bang bang clip clip?

MartyZero · Jan 26, 2015

For this you need compressed air:
Find a file with a round wooden handle that is bulbous at the rear. A smaller file works better. Holding the file by the tip with the handle sticking up put an air nozzle close to the handle where it joins the file and point it up towards the end. The flow of compressed air will make it float a small distance away from the nozzle. Oooh magic!

allloutmx · Jan 26, 2015

Put a blindfold on and let them ask you any question they want, and prove to them that "Machinists" do in fact know everything...
Good luck Denis

Mcgyver · Jan 26, 2015

i made some of those double ended bolts with a nut in the middle of out brass, they always attract lots of attention from non machinists.

The other classic is the cube in a cube in cube apprentice task.....here's one I made....I guess you could sort of say its 'magic' to those who know nothing of machining etc.

Screwmachine · Jan 26, 2015

This one is dead simple but I've seen it fool some pretty clever people:

weld the nut to the loose bit of bolt (threaded about halfway in the nut), slide a loose fitting split lock washer on and then screw the nut to the bolt. The slot(s) in the head make it seem like the lock washer can come off when manipulated correctly. If you hand tighten tight those who suspect it's a false weld will be fooled. You take it, turn around, and a few seconds later the washer is off.

There's also a well known trick among magicians called "Scotch and Soda" that has a machined out half dollar that requires a little prep to perform but blows people's minds. Google Scotch and Soda Trick to see some images. I had it as a youngster until my brother took and spent the trick half dollar.

Been meaning to make one here with Swiss coins...

Limy Sami · Jan 26, 2015

Everything I make that comes out right is magic - there can be no other explanation!

stephen thomas · Jan 26, 2015

Not a cool as the previous dynamic demonstrations; but as an additional conversation piece, I've made a two headed penny in the past based on instructions a number of years ago on this forum.

Basically turn the back ID out of the back of a coin to 1/2 depth leaving the rim. Then turn just the rim off a second coin, and face the back off to 1/2 thickness. Done just so, the pieces will snap together and the coin will look OEM but always come up heads. I don't have the chutzpah to pull it off, but a practiced magician can entertain by dexterously using a real coin and alternating them while giving a spiel about how machinists are so adept that they can flip heads at will, etc. even letting an audience member try it while passing only the real coin. Mine never came apart while flipping, but some on this forum recommended putting a bit of solder and some flux between the parts, and heating on a stovetop to sweat them together more permanently.

Actually made mine to give to an old time circus performer who in his 80's was getting by delivering materials to our jobsites. He always had a new puzzle in his pocket or trick to show after the materials were unloaded. Unfortunately, by the time I began carrying the coin in case "Uncle Bobby" showed up, he had some memory incidents and was retired from driving for the company. So I gave it to a Ukrainian co-worker who enjoyed similar stuff.

smt

emcmike · Jan 26, 2015

Your money showed up here .......Thanks Bob

dgfoster · Jan 26, 2015

The response to this inquiry has been great. I was worried all I would get was an eye-roll and maybe a tongue lashing.. Maybe this thread will serve not just my needs but will e a repository for a whole bunch of ideas for future reference. Thanks to all who have responded so far. Sorry for those who lost money, but it seems to have been made up for by Mike.

Denis

smalltime · Jan 26, 2015

The Littlest Engine That Could: World's Simplest Electric Train @ AMERICAN DIGEST

REALLY cool trick.

Anybody have any machining based magic tricks?

Diamond

Titanium

Diamond

Stainless

Diamond

Hot Rolled

Stainless

Diamond

Stainless

Diamond

Stainless

Plastic

Titanium

Diamond

Titanium

Diamond

Diamond

Hot Rolled

Diamond

Banned

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