Magnetic Propeller Balancer




So you have spent a lot of money on your diy quadcopter(or any multirotor) and refuse to give any more, but you still need a propeller balancer. Balanced propeller is very if not the most important thing for multirotors.

Guess what, you can make your own, from old computer components.

If you happend to work in ICT company, there is always a lot of that stuff around. Besides broken hardware, some tools may also come handy. Let's begin with stuff you are going to need.

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Step 1: First Things First

If you are lazy and don't care about 20 bucks, go and buy propeler balancer. Go for a booze right away.

Step 2: Stuff and Tools

1. Piece of wood,

2. Set of screw thingies,

3. Drilling machine,

4. Handsaw,

5. Angle grinder,

6. Broken DVD writter,

7. 4x Hard disc drive,

8. Rack server,

9. Hammer,

10. Ruler and

11. Sandpaper.

12. 2-8x Pen

Step 3: Disassembling Hard Disk Drive - Harvest Magnets

Disassamble hard disk drive with appropriate screwdriver. Make sure you have made backup before. If you are stuck with some plastic hooks, take hammer and brake them. Repeat as many times necessary. Don't worry about hammer and you can't overdoit smashing hard drive. Now if magnet is free to take out, take another hard disk and repeat this step 3 more times.

Now you should have 4 magnets. If you have less, you don't know how to count or you dissasambled some SSD or whatever.

Step 4: Disassembling Hard Disk Drive - Harvest Metal Axle

Use screwdriver to unscrew all screws. Now, it won't allow you to open it just like that. Help yourself with hammer, convince him. Eventualy all vital electronic parts will move away in several dozen pieces. Take out shorter axle and throw away smashed DVD writer into garbage(recycle!). Or you can intall into colleagues PC. Either way is ok.

Step 5: Rack Server - Harvest Hdd Case

Download manual for your rack server and find a way which one of 2 possible plastic handles enables taking out hdd case. After that, unscrew 4 screws or 5 or 6, depends on the case. All you need from this are two metal side thingies. Rest of the case you can put back into rack server. Then you can practice hammering on server.

Step 6: Drilling Time

Find somewhere in the workshop 3mm bore. It will fit with almost any screw from bowl of screws.

Most certanly you will find 2mm and 4mm. If that is the case, call your boss and tell him that workshop doesn't have 3mm bore. Then go to the hardware store and buy it. Next day you will notice few evil eyes in the office.

Make two holes on each side of wooden piece with cool black stripe. Make sure those wholes actualy fit in metal thingies from hdd case. It is recommended to use angle ruler. If you have sharp eyes and good normal ruler, it will be fine. I didn't have angle ruler.

So now you have 2 holes. Take 4 screws from bowl of screws. Screw them. Screw them good.

If everything is screwed good, you will have 80% of the final product.

Step 7: Steel Some Pens

Steal 3-4 pens from office. Don't use your pen, it's more fun to steal from colleagues. Next day they will be surprised. Blame the janitor the cleptoman.

So now you are full of adrenalin because you stole 3-4 pens. Unscrew(without screwdriver) pen tip thingie. Use the adrenalin from stealing and take sandpaper and sandpaper them. Also sandpaper them goood. The point is, we need get enough big whole for pen tip thingie go through metal axle from dvd writer. If you overdo it, go and stil some more pens. Enjoy the extra adrenalin. Feels good? :).

I hope the office had enough pens for you to make 2 sandpapered pen tips thingies.

Step 8: Sharpening Metal Axle

Roll your sleeves and take angle grinder. Each second you are becoming a more manly man. Beard is growing 1mm/hour. Grind metal axel to get sharp edges. Grind it until is about 5mm shorter then U profile made from piece of wood and 2 metal thingies. If you wish, you can use handsaw for shortening first, then grinding to get sharp edges. Either way is ok. Depends how much beard do you want to grow that day.

Now you are 95% finished.

Step 9: Finalising

Rest 5% is asembling magnets on metal thingies. Put pen pins into metal axel with propeler between. Friction will help to stick 3 things together.

Congratulations you are finished. 20 bucks stays in pocket, speend it on booze.

May you multitorors fly without any vibrations and the force be with them.

p.s. Stolen pens problem have few solutions. Burn them! Blame on janitor the cleptoman. Take a vacation 2-3 days.

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57 Discussions


2 years ago

Great post, had me laughing all the way through it. Other than the questionable concentricity of the stolen pen nibs (not that it should have a huge effect on a 6" propeller, being so close to the centre of rotation), it looks like it should do a reasonable job. Thanks for posting this.


3 years ago

My father used to build wood propellers for small aircraft, late 1950's through the 80's. This was the same "type" of tool he used, but on a smaller scale. He used a couple of vertical 2" x 4" 's about 4' tall on wood base to hold them up, with a couple of old wheel bearings. You just need to hold the item you are balancing in space. I've also seen it done with two pieces of wood with a notch on the top of each to hold a rod. The propeller does not need to be vertical, it can be horizontal as well, it just needs to be able to move freely. The second "must be" is it has to balance through the center axis. Which is usually a hole, so you have to create something to center in the hole. The use of the cones from the ends of couple of pens to center the propeller on it's axis used in this instrucable I found to be very ...ingenious!


4 years ago on Introduction

Somewhere the dimensions, of the parts needed to be made, were deleted along with the instructions on how to use. I've read this 4 times and even having a mechanical engineering degree has not help me understand how to build this or use it. Most of the written text either does not apply or makes no sense at all. what a waste.

3 replies

Reply 4 years ago

Bro, I'm in highschool and I could tell exactly how it was made and how it works from a few pictures. I think you may be over thinking this, it's extremely simple.


Reply 5 years ago on Introduction

Step 4: Disassembling hard disk drive - harvest metal axle

That should be not hard disk drive

Should be cd or dvd drive


Reply 5 years ago on Introduction

I am older than you I bet!

Nice instructable, I don't have a large quad copter, but my roommate does, and I am going to show it to him, maybe even have a go at making it.

When I started work in the US, I was using 8 inch floppies, beat that if you can. And my very first hard drive drive as a 20 MB, ST225. 20MB, YOU CANNOT BUY THUMB DRIVES THAT SMALL TODAY.

(Glad you took the last comment as a joke)(and I lived in a paper bag in the middle of the street)

Later everyone