Introduction: The Bolt Puzzle

Picture of The Bolt Puzzle

This instructable will show you how to make a great pocket sized puzzle. Great for a gift.
P.s. This was not my idea credit goes to This Site . However the pictures are my own.

Step 1: Materials and Tools

Picture of Materials and Tools

To make the Bolt puzzle you will need:

A left-handed bolt (For size, look at the picture) and matching nut.
(By the way you can also use a right-handed bolt if you don't have any left-handed bolts, I have used a right-handed bolt and not had any one guess it thus far. However the puzzle will no doubt work better with a left-handed bolt.)
A split washer (Notice that I split it more, see picture).

A file for metal.
A saw for metal.
A welder.
A vise.

Drill with wire brush attachment.

Step 2: Step 1

Picture of Step 1

Now take your bolt and put it in the vise. Then file out a v-shaped notch on two of the bolts sides(See picture 2).
Note: These notches do nothing, But most people will think they are the key to solving the puzzle.

Step 3: Step 2

Picture of Step 2

That done cut off a piece of the bolt, about a quarter of an inch of the end of the bolt. (See picture for help).

Step 4: Step 3

Picture of Step 3

Now screw the small piece of the bolt about a quarter of the way into the nut (see picture). Make sure you don't screw to far in otherwise the other piece of the bolt will not fit in nicely. Next weld them together just like in the picture.

After welding you will notice that there is a fair bit of heat discoloration on the the metal. So using the wire brush attachment on your drill buff the bolt so it is nice and shiny or you can use aluminium spray paint.

For those who don't have a welder here is some great ideas:

If you don't have a welder you can use a blowtorch (or something similar to heat up the nut and piece cut from the bolt) and some solder.
(Thanks kasssa)

Or You could also use a dab of JB Weld to secure the nut and piece of bolt.
(Thanks CimarronWarrior) 

Step 5: Step 4

Picture of Step 4

Now all you have to do is put it together. Look at the picture for help.
Great, you're done, Now all you to do is choose your "victim" and ask him to remove the washer without bending it. He will most likely struggle with it for about 5/10 minutes before giving up. Make sure you keep telling them that it is possible and is pretty simple, otherwise they give up sooner. When he gives up put it behind you back and remove the washer. Then put it back together without the washer. Give this back to him and if he still can't guess, go ahead and show him. He deserves it for the time you wasted.

Wiggly bolt<>Sometimes the bolt doesn't screw tightly into the nut. So it gives the trick away,so what you can do is give the end of the bolt that's going into the nut(The nut that is welded to the small piece of bolt) a couple taps with a hammer this makes it harder for the bolt to be unscrewed. Careful to much and you'll need a pair of pliers to unscrew it, which kind of ruins the puzzle.
P.s. If you see any problems post a comment about so I can fix them.


scraptopower (author)2011-08-16

You should make one that can't be opened at all, and one that can. Alternate between giving the dud one out and solving the real one , would it drive everyone crazy ? :o

Mattrox (author)scraptopower2011-11-30

Good idea!

FriendOfHumanity (author)2010-12-22

I was skeptical that anyone would fall for this but I had to find out.

I made it with slots that go right over and through the head and a washer that almost makes it possible ( the leading upper edge of the washer and the angle of the slots make the person actually tighten the bolt as they try to get the washer off).

Anyhoo, the results are as follows:

1- 11 Year old girl; solved in 5 minutes.
2- Woman with no real mechanical background; solved in 2 minutes.
3- Male mechanic; gave up after 30 minutes.
4- Another male mechanic; gave up after 20 minutes.

It is very funny watching the disgust they have with themselves as they are told the solution.

Mattrox (author)FriendOfHumanity2011-04-29

Yeah this puzzle is great because to most it is illogical. They look at it and see a bolt welded to a nut, "obviously" the nut will not come off. A mechanic is going to see the weld and imediately assume the nut ain't going nowhere. Whereas someone with less knowledge will try anything.

SenKat (author)2010-12-27

DIABOLICAL !!!!! I LOVE it ! I've seen this 'ible a few times and never read it - VERY Glad I read it today, though ! :) Thanks for the entertainment, I cannot wait to try this one out of my Mom and Dad ! Wooo-hooo ! ESPECIALLY my arrogant, "holier-than-thou" Brother ! Muahahahahahaha ! Thank you VERY much - 5 out of 5 !

robosilo (author)2010-12-24

this was a funny project. I had funny building it and fun watching people try and solve it. it made for a great stocking stuffer too.

FriendOfHumanity (author)2010-12-19

I like this a lot .... I'm making one today.... the notches are very good touch.

Mattrox (author)FriendOfHumanity2010-12-19

Yeah they distract the person doing it. When they look at it they see the notches and immediatly think it is part of the puzzle.

Housedog (author)2010-12-18

Really cool! I finally have an excuse to buy that welder I've been wanting for years. Nobody would figure this out, unless by accident.

josht (author)2011-03-23

I would really like to make one of these, but I cannot for the life of me find a left handed bolt. Where is everyone getting theirs?

Willys36 (author)josht2018-01-03

I have a local bolt supply house. Can get just about any fastener known to man there!!

jpnagle59 (author)2011-07-21

Nice brain candy...I wonder if Loc-Tight woud work? I was also going to say that you could get a Uni-Strut nut (1") in length, and Loc-Tight to hold the end welded piece, with out having to use a welder. The suggestion of GB weld is a good one.

Willys36 (author)jpnagle592018-01-03

Unfortunately the trick really needs the weld showing to convince the contestant that the nut won't unscrew.

tpartic-gray (author)2011-09-17

one drop of superglue will do the trick if you dont have a welder

Willys36 (author)tpartic-gray2018-01-03

It is the weld that convinces the folks it cant unscrew though.

MaXoR (author)2010-12-19

What stops a guy from simply twisting the bolt during his attempt to take the washer off? I know the first thing I would do is try to take off the nut, and during that process, what is going to stop me from then accidentally unscrewing it? Especially since you state it's possible for the original person to just twist it off behind their back.

This seems like a game that only works on people with an IQ under 70. So I would find a way to not have the "prey" be able to open it, and WAY MORE important than that is... you MUST have UNIFORM color on the bolt!! Anyone with an IQ over mentally disabled, will wonder why there are two colors. (And if they think far enough that the WELD discolored it, then why would the other side not also be discolored. I think the JB weld would work the best, since it can be hidden better, and won't discolor the bolt sections)

Willys36 (author)MaXoR2018-01-03

Actually as mentioned above, the guys with the most knowledge will likely 'know' the nut can't be unscrewed. Also not he specifies a left handed bolt which most folks will instinctively try to unscrew it right handed which tightens the left handed one. I am going to try it.

laptop_geek (author)MaXoR2010-12-19

Never learned about heat transfer did you? The other side could easily not be discolored because the bolt absorbed enough heat to keep the other side cool.

If you tighten the nut so that it is not easily removed (but not enough that you can't undo it) then it'll be fine. the weld also keeps people from trying to remove it (looks like its stuck), JB weld would not have as good as an effect.

jadronx (author)laptop_geek2011-12-23

it looks better when both sides have been looks uniform and clean

Nelson_Yepez (author)MaXoR2010-12-21

The point is that they see the weld so they wont even try to unscrew it because is WELDED. Your idea of using JB weld is a good idea (not), you should do it and then you can use it on people with an IQ of under 40 that also think is a good idea.

ss3e55 (author)MaXoR2010-12-20

That's correct! The person writing this has missed the single most important part of the puzzle....its supposed to be a left handed thread bolt that you start with.

The site where they took the puzzle from explains it properly, and they were nice enough to quote that orign.

Incidentally this seems just like a reprint of that one - albeit with photos of their own model.

Next time they should read the original more carefully and understand the puzzle...obviously without a left handed bolt this is trivial.

Gorilla22 (author)2016-02-18

Could you link to where you got the bolt? I can't find one.

Gorilla22 (author)2016-02-11

Oh, I get it. The nut holds the two pieces together. When you want to solve it, you unscrew the nut. This is geneus.

bobes360 made it! (author)2014-04-01

Thank you for posting .. this was my first puzzle I made and I have to say I love making puzzle. Here is picture of my own:

c3ralki1l3r (author)2012-12-05

could i use jb weld ?

Mattrox (author)c3ralki1l3r2012-12-11

I'm sure that would work. :)

ALogan97 (author)2010-12-20

that's awesome! would soldering work instead of welding though?

jadronx (author)ALogan972011-12-23

it will work fine if you have a nice hot torch

arpruss (author)2011-12-03

Wow: I had no idea left-handed bolts were so expensive. Fastenal's 1/4-20 left-handed bolts start at about $11.58 .  McMaster-Carr's prices are in the same range.  Has anybody found a cheaper source?

tech dawg (author)2011-12-02

this is amazingly clever ....................I LOVE IT!!!:D

Wasagi (author)2011-08-27

I really like this idea!

dreamberry (author)2011-08-15

My buddy made one of these and left it at my house, I leave it out during parties and watch people go nuts trying to figure it out. It's a good trick, but it's almost reached the saturation point, where not too many people Haven't seen it, around here at least.

Cubie2 (author)2011-04-28

Ha! I love puzzles like this where the solution has nothing to do with what everyone thinks it is!!

improyo (author)2011-04-21

great idea i made one and no ones guesed it yet....

Ivan Denisovitch (author)2011-01-23

Great puzzle! I made one and my boss still hasn't figured it out. It seems to help that I cut a few different notches on the bolt head, so people keep trying to find the "right" one.

davidpeck (author)2011-01-18

I made this for my 10 year old son for Christmas. I didn't do a good job setting up the scenario so he solved it by accident, but he's had a blast foisting it on others. Fun little trick puzzle.

jackatronix (author)2011-01-08

surely they would work out that they need to unscrew the nut
and when they do the small piece of the bolt will come off with it
then they can just slide the washer off of the big piece of the bolt

codongolev (author)2010-12-21

on the other website, it said to buy a left- hand bolt. that seems to make more sense, because I would think that the first instinct people would have (even seeing the weld) would be to try to unscrew the bolt, which would ruin it.

nimster64 (author)codongolev2011-01-06

thats a great idea also. so if they try to unscrew it they are tightening it LOL

nimster64 (author)2011-01-06

the weld is there as a illusion to make the victim think that the nut is welded to the bolt so it can't unscrew and the only way out is through the head of the bolt. that will prevent the victim to try to unscrew it. LOL great Job I must make one

ybilou (author)2010-12-21


For this to work, you need to use a left hand bold (reverse thread). Otherwise it is quite easy to unscrew instintively.

pfdanielson (author)2010-12-18

I love this! if only i had a welder...

You could drill a hole where the weld would be and put a split pin through instead.

Thats a good idea now i think i might have to make this!

beehard44 (author)pfdanielson2010-12-21

JB weld? Solder? Brazing?

jamieinvents (author)pfdanielson2010-12-20

Yeah, thats what i thought too cause im only 14 but the two things i did were either use a oplastic toy bolt and melt it or when i made a mettal one i used epoxy rather than welding

jinxleah (author)2010-12-21

Wonderful trick!

A classmate of mine made this. He slanted the notch to make it appear that if you twist the washer just so, and get it in just the right position, it will easily come off. He also made the weld very obvious, so we "knew" that it wouldn't just screw off. In a class full of metallurgists none of us, including the teacher, were able to figure it out. When he simply unscrewed it, we were all thunderstruck. And quite a few of us ran to our welders to make one for ourselves!

Also, for those reading this comment who want to learn welding, check with your local community college! They may have classes, and from what I've found, they've got excellent rates! My community college's credit hours cost less the $40. Also, a very cheap welder will cost you about $100, and you can probably find YouTube videos of someone using that exact welder.

moosamech (author)2010-12-21

hi 2 al

qorlis (author)2010-12-20

I have one of these with notches cut into the threads instead of the head. If you do this, be sure the notches can't allow the washer to slip off when your "victim" works on the puzzle. Basically, they give the same impression as the notches in the head. In fact, you could do both.

awz123 (author)2010-12-20

Dang, too bad all my friends visit instructables everyday, I would really enjoy seeing them attempt to figure this one out...

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