Picture of Glow in the dark keyring
Awesome, Awesome, Awesome mini project that i recently discovered on this web site:

It will be my next project for my after school engineering club. Check the vid to see the key rings in action!

Learning Objective

By following a detailed set of instructions and videos from the Instructables website, yr9 students (13 year olds) will make a glow-in-the-dark key ring. The students will recall previously learnt skills on the metal lathe, e.g. facing off, centre drilling, and drilling to a given depth. This project will introduce the students to a milling machine and an indexable head. The project teaches how to use these precision tools to a high degree of accuracy and the students must aim to work within a tolerance of +/- 0.1mm. To achieve this tolerance the students will have to use basic mathematical calculations of linear measurements and angular divisions.
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Step 1: Cut material to length

Picture of Cut material to length
  • Use a hacksaw to cut either Ø9mm brass or aluminium to 90mm long

Step 2: Drilling

Picture of Drilling
  • Centre drill
  • Drill Ø6mm x 50mm deep
  • Drill Ø6.8mm x 8mm deep

Step 3: Tapping the thread

Picture of Tapping the thread
  • Put a M8 tap into the chuck and manually tap the thread. Do not turn the lathe on!
  • Once its started remove from the lathe and complete the rest in a metal vice.

Step 4: Y axis (centre)

Picture of Y axis (centre)
  • Remove the work piece from the lathe and secure in the indexing head.
  • Put in the centring bar (this can be any rod with a known diameter)
  • Slowly advance the rod towards the work piece, using a thin piece of tissue as an indicator......keep moving the tissue, when the rod grips the tissue you know its exactly on the edge of the work piece.
  • Lower the machine bed and zero the Y axis dial.
  • Use the following calculation (Ø of centre rod + Ø of work piece / 2)
  • 8mm + 9mm = 17mm       17mm / 2 = 8.5mm
  • Move the Y axis dial 8.5mm
  • If done correctly you should be within +/- 0.1mm of the centre
Very nice version.

Not too sure about the glass if you drop it? Acrylic rod is cheap :-)

Glad you liked the idea ;-)

jonnyd55 (author)  divided head3 years ago

The glass is pyrex so its pretty tough and when bought through the schools science department its surprisingly ......cheaper than acrylic!

You should definitely put your LED torches on instructables people will love them :)

Hi Jonny,

Fair enough, just a thought on the glass :-)

Not upto speed on how this all works yet.... But the torches will be possibly the only thing I try as the keyring projects are the simplest things I make.

Glad you can link to videos on here. That'll save hours. The torches are a little more complex than these! :-)


jonnyd55 (author)  divided head3 years ago
..I have made two of the torches as well :)
Ahh, good man :-)

Well if I can't get this site figured out I'll let you know.... you'll have to post that build too! lol

I like your gearbox lamp BTW. Top job.

black hole3 years ago
Amazing. Are you going to sell these? I would love to own one.
P.S. I voted for this and for your aluminium keyring. Good luck!
jonnyd55 (author)  black hole3 years ago
Hi, thanks for the vote.....unfortunately all my spare time is consumed by instructables.........Robot, please can i have my life back!
zakamooza3 years ago
wouldn't be easier to use a tube instead of using a solid rod and drilling the center?
jonnyd55 (author)  zakamooza3 years ago
Hi, yeah sometimes that is possible and saves loads of time, however, tubes are no good if you need a solid end..... or..... the internal diameter of the tube can sometimes be too big....or....the wall thickness too thin. But occasionally tubes are awesome :)
ok, i would try this if i had the right equipment :(
Kryptonite3 years ago
Absolutely amazing build, may I ask what inspired the make?
jonnyd55 (author)  Kryptonite3 years ago
Hi, thanks :) the idea is not mine :( if you go to the intro there is a link to the website where i found the idea jonny
Ahh, I missed that! I love how you made yours different and unique.
what about using tritium vial with a plastic coating? outstanding project by the way! i hope to get a lathe and milling machine in the future.
jonnyd55 (author)  desertsniper3 years ago
Thanks.... get them sooner rather than later........ Lathes and mills are the coolest machines..........dare i say it even cooler than laser cutters! if you are in the uk and want advice on where is best to get the machines from, let me know :)
Well i live in the united states, but i will definately ask you if i have any questions! i need to buy a new belt sander (i just burned the motor out on mine) then i need a knife belt grinder and a forge. after i get that equipment i plan on buying the milling and lathe gear.
I live in the south east of England. do you know where i could get a cheap lathe or milling machine as i am a student.
jonnyd55 (author)  boris4003 years ago
There are a few different options, what's your budget? And what sort of things are you interested in making?
My budget is as cheap as possible. i really wanted to make small projects like your glow in the dark key chain above and some small model steam engines etc. so its nothing too big.
jonnyd55 (author)  boris4003 years ago
Hmm then i would suggest ebay or gumtree and buy a second hand one it just requires a bit of time to wait for one to come available...however.....if you are unable to collect a heavy lathe or just want a new one then dont spend less than £600 or it will be rubbish...... the cheapest machines are from axminster or chester tools. if you are looking at a particular machine, and would like my opinion of it just email me on my instructables account.
You could build a cage around the plastic vial, but you can't open it. The phosphor is on the inside of the plastic vial and that is what glows.

The Tritium is emitting beta particles which only travel a short distance through the air--something like, 1/4 of an inch i think--and it completely blocked by the layer of dead skin cells on your body. So it is safe, but you can't get it out of the bottle without it getting messed up.

Good thought though!
yeah, i was not talking about tranfering the tritium gas and phosphor, just putting it in a plastic tubing you protect it from bumps. then inserting it in the key chain.
canucksgirl3 years ago
Hey that looks neat. Almost looks like a bullet casing. I wonder if that couldn't be modified into a glow in the dark key ring... hmmm?
jonnyd55 (author)  canucksgirl3 years ago
Hi, yes one could.....unfortunately bullets in the UK are not easy to find or legal! :( Strict British rules on fun frown upon guns.
wow.... I didn't know that. Here in Canada, we're not as "gun happy" as our neighbours to the south, but getting bullets isn't much of a problem here... Don't they have firing ranges where you could scoop up some spent rounds?
jonnyd55 (author)  canucksgirl3 years ago
I could be wrong but i think we are only aloud 0.22 rifles in uk = tiny cartridges
Osquar jonnyd553 years ago
If you have a hunter friend with a so called "elephant gun", maybe he has a couple of empty casings? My dad has one of those and the casings are, I think, big enough.
Only .22 in the UK? I have a few clips of deactivated 5.56 standard NATO rounds, AK47 mag and rounds (deactivated), 1 inch minigun round, anti aircraft round, and quite a few blank empty cases.
jonnyd55 (author)  dr_insane3 years ago
blank rounds yes.....but..... whats the biggest live round we are allowed in uk?
I know here in Ireland I legally own a .222, the cartridge on them is similar to a AK47. Im not sure on UK laws though, .22?
Its 7.62mm i think
If not, its what ever your firearms ticket allows you to hold.
I know you can hold 7.62mm rounds with a valid ticket.
Do shotguns count? I'm pretty sure you can have a 9mm pistol if you're in a club, which is bigger, but smaller than a 7.62.
And if you're thinking seriously large some people have cannons(if you live in a castle), but they don't have cases.
Also apart from the crimped end, why wouldn't a blank case be suitable for most projects?
A GITD Bobby's Truncheon perhaps?
JonC3 years ago
Very nice idea.

I know you can own quite a range of rifles in the UK, I have friends who own .222 and .308 rifles which are considerably larger rounds than .22 but still a way off the 9x90 mm given in the description. For this you need something like a .50 BMG which again can also be owned legitimately in the UK but would be very difficult to obtain the license for as you are required to explain to the police what you need it for!

My advice if you want a rifle round shaped one is buy some larger brass (12mm or .5inch and while its in the lathe turn the end down to give the correct shape and thread it internally as per the guide. then use either another bit of the brass another metal for a contrast or buy a bolt of the correct thread and turn it to a curved point on one end similarly to the instructable. Also casings tend to be quite thin and would be difficult to drill leaving a clean hole.

This will certainly be easier than trying to find .50 BMG casings!
jonnyd55 (author)  JonC3 years ago
Hmmm........ Would the police accept 'key rings' as a good reason for a 50 cal licence? you raised a good point about the casing being difficult to machine! ...........Oh and for any one thinking of making a bullet version......please......please.....please ensure you empty the powder before you drill it!!!! ;)