HandGrinder for Less Than $1




Introduction: HandGrinder for Less Than $1

About: 15 year-old maker from Argentina, who loves making his own tools. I'm interested in electronics, electric vehicles and good ideas. Waiting for a spanish Instructables version!

Hi, this is my first instructable. This project is very simple and easy, you can do it in about half an hour.
Maybe you have seen some sanders made of old HDD´s but this tool can sand, polish and cut.
I've got the idea from: https://www.instructables.com/id/Recycled-HDD-Powertool-Disk-of-Prometheus/
I didn't take any photos during it's construction but with the images and diagrams you will able to do it.
You can cut bolts and screws, it's very safe, the blade won't break because it doesn't have too much power, and if you use it wrong and you jam it the thing will stop preventing breaking things.
This is a very useful tool when you need to repair your bike, like cutting old chains.

Step 1: Tools and Materials

Almost everything in this tool its recycled, except the zip ties.
- Torx screwdriver set (I buy it and used it for a lot of projects, price for a 6 pieces set: $2)
- Maybe some glue
- Soldering iron

- Tape
- Some screws (From old stuff)
- A piece of wood (recycled from a fruit crate)
- Some thin wire
- Momentary switch
- Zip ties about 6
- A HDD that you can remove the motor, in some models its fixed to the mainframe, we can't use this ones.
- RCA female connector and male wire (both recycled)

For the power supply:
If you will use an AT/ATX power supply you just will need to plug it in.
BUT, you can use batteries (two 9V) or a 12V power supply.
For batteries:
-2x9V batteries
-L7812 and L7805 power regulators.

For 12V power supply (you can make one or recycle one from a VHS recorder or other thing)
-Just a L7805.

Step 2: Diassemble the HDD

I didn't take any photos for this step but its very easy. Remove all screws, keep the motor, the PCB and the screws that fixes the disc. You will need to keep the separators and all the discs too.
You can find more information on the internet. Sorry!

Step 3: Assemble

You can easily assemble this tool looking at the pictures but there are some things that you will need to know:
There are 3 terminals in the motor solder one wire to each one and then solder that wires to the terminals in the PCB.
Look at the diagrams to make the electrical connections.

Step 4: Finished and Some Ideas

You can adapt a cutting blade like I did. Just take the center metal ring and with a sand or a dremel make the hole bigger, in every HDD I disassemble the center hole diameter its 1".
It's not my responsibility what you do with this tool.
Don't use it for illegal purposes.
Use safety glasses!!! Always watch the blade, don't be too close to it.

You can make a safety cover like in the pro tools. I will make it you should do the same.

Thank you for watching!

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    10 years ago on Step 4

    I know it's very dangerous, but the disk won't break, the motor doesn't have too many power so it will stop and it won't spin again until you switch it off and on again.
    Thanks for your comment.


    Reply 10 years ago on Introduction

    great job. It could use some sort of protective shield, but your idea is still amazing!

    Dr Qui
    Dr Qui

    10 years ago on Step 4

    This is very dangerous, if you value your eyesight, fingers or health in general save up and buy a cheap angle grinder.

    A hard disk motor spins way faster than the maximum speed an angle grinder disk can safely be used at, when the disk wears down it may explode on you.  you also mention that you "adapted" the metal reinforcing ring of the disk, NEVER DO THIS that metal ring is to reinforce the disk and by tampering with it you have weakened the disk.

    Check out the disk of Prometheus ible  make a high speed sander out of it and you will not risk losing an eye, cutting a tendon or artery that leads to a blood infection and later death. My brother-in-law's father died from an injury caused by an angle grinder, since this happened I will not use an unsafe grinder.

    For fourteen you have done a great job, I do like your thinking, MacGyver would be proud of you for making this, he would have escaped from the bad guys and be well on his way if he had this, but...

    You should stop using this before you regret using it.


    10 years ago on Introduction

    Gracias por tu comentario, voy a ponerle un protector, deberia haberlo hecho antes.
    Thanks for your comment, I'll build a protector shield, I should do it before.