Recycled HDD Powertool (Disk of Prometheus)

UPDATE 09/04/2011: Hey guys, I have entered the Disk of Prometheus in the Green Living and Tech. Contest, Please VOTE for me!!

In my last instructable related to recycling old HDDs, I had designed a sander from a junked HDD for as little as $5. But, the old design had its limitations and i had got a lot of people writing to me about improving the design to increase its usefulness. You can find the old instructable here

The older HDD sander had its motor still attached to the HDD base, thus limiting its use. In this instructable, we're going to design a power tool using an old hard disk , which can not only do sanding, but also cutting, polishing(buffing) and it may also be equipped with a diamond blade to cut glass.

The HDD motors spin at a very high RPM, but do not have much torque,but once they get into full speed('bout 7200 RPM) it is enough for our grinding/ sanding/buffing etc. purposes.

WARNING: The HDD is not a plaything. The platters spin at a very high speed, making it easy for the sander to rub your finger raw. I am not responsible for any damage you do to yourself or to anyone else near you.

Step 1: Materials Needed

For the project we are going to need some cheap stuff. The list is pretty much same as the old HDD sander with a few additions.

Parts:

• A junked HDD(needs to spin up!!)
• ATX PSU
• A Woodenruler
• Wires (single-core preferred)
• Zip Ties (VERY IMPORTANT)

A wooden ruler may be difficult to come across nowadays. So, a piece of wood with the same dimensions will also suffice.

Optional: (for more info. go to Step 7)

• Sponge
• Diamond-edged Blade
• Sand Paper

• A brushless ESC like the one here (Step 8, Part 2)

Tools:

• Torx Screwdriver set
• Power Drill
• Soldering Iron
• Soldering hot plate(optional)

Step 2: Diassembling the HDD

Start by peeling off all the stickers on the body of the HDD. Particularly the ones with "WARRANTY VOID IF SEAL IS BROKEN"

This will make all the Torx screws visible.
Unscrew all of them, on the side with the steel shield which protects the HDD.Carefully open the screws on the PCB side(other side) and remove the PCB for now as we will need it later.

Even after you unscrew all of the screws, it might seem as if the shield is still attached to the body. Inserting a flat blade screwdriver into the gap, pry it open, very gently.

After doing this, put the shield away and behold the guts of an HDD.

You will see 3 things. The HDD platter, the actuator head and the powerful rare-earth magnet. Pry away the magnet from the body and keep it for future projects.Also, slide out the actuator head and also store it.

Unscrew the platter screws so that the motor is exposed. There is a spacer between the motor and the platter.Store this also. The final step is to unscrew the motor from the HDD body so that we can fit it elsewhere.

Step 3: Assembly: Drilling the Holes

The first step in assembling our to-be power tool will be to drill holes according to the following plan:


We will drill holes for the motor and for the controller/driver on each side of the ruler. This step is pretty much self-explanatory. I just recommend you use a power drill with wood-cutting bits. Most rulers are a type of compacted MDF or compacted sawdust and you shouldn't have any problem in drilling right through.

Step 4: Assembly: Soldering

Now we need to solder the controller and the motor by using some wire. I recommend single-core wire. There is not much to write about this step - all you have to do is to solder 3 wires to the controller and the other ends to the respective motor contacts.

The pictures below explain this step thoroughly.

BTW, my soldering is not that messy. I just melted the solder onto the terminals, clipped the wires to the PCB and put it on a hot plate so that the soldered joints self-centered.

Step 5: Assembly: Fixing Everything Into Place

Now that all the drilling and soldering is done we can finally attach everything to the base. This step is very simple.

First we will screw in the controller PCB. You can use the original Torx screws for this purpose. After that you can zip tie the wires to the base to make it firm.

Now is the tricky part. We will need to zip tie the motor to the base. You may wonder why don't we just screw it in using long screws, but the zip ties are there to absorb vibrations. They cushion the motor so that vibrations are not transmitted to your hands. They act a bit like shock absorbers in a car .

Also they don't fall off like the screws, which I had used initially but could not withstand more that 2-3 spin-ups before they fell off or got so loose that the motor was close to flying off.

The pictures show you how to use the zipties.

After the motor is attached to the base, we can attach the platter to the motor. Remember to use the spacer which we kept away in step 2 and attach all the screws to prevent any damage when the motor spins up.

Step 6: Power Considerations

If you use your power tool on-bench, an ATX power supply with no modifications will do OK, but if you work a couple of feet away from your PSU, you need to extend the power cable by using a male and female molex/SATA connector with a long cord in between. Remember to use heat-shrink tubing at the joints.

OR, you could just buy one according to your needs from here
http://www.coolerguys.com/powerext.html

Now, that isn't the DIYer attitude,is it??? So I built my own 10ft long extender cable for the power tool.

Tip: You need to short the Green Cable on your PSU to any of the GNDs to make it power up.

Step 7: Tool Blades

The interchangeable nature of the HDD power tool is what makes it suitable for a range of applications. The following blades can be attached to the platter for different purposes.

Sanding Blade:

Same as the old HDD Sander. A Disc of sandpaper fitted onto the platter with or w/o glue. More info here

This can be used to sharpen knives too. Test results same as old HDD sander.

Diamond-edged Blade:

You can sandwich a diamond edged disc cutting blade as shown here to turn your power tool into an HDD glass cutter.It could also be used to cut traces on a PCB.I have not tested this yet. Waiting for my blades to arrive. You can get diamond-edged blades here.

You have to fix them as shown below. You will need another platter. HDD motors need to have a long life-span so they have ultra-high quality precision-balanced bearings making it absolutely perfect for our purposes.



Polishing/Buffing Attachment:

You can attach a sponge to the platter using water-soluble glue/screws to use our tool to polish surfaces.

More attachments to come soon.If you have any suggestions, leave them in the comments

Step 8: Troubleshooting

If you have any problem in starting up your power tool for the first time, try these steps:

1. Check solder joints on both the motor and controller for short-circuits. If found,clear them and try again.

2.If the controller gets very hot /smokes/ignites, you have a short somewhere and I am sorry to say that your controller is fried. For info on how to solve this, scroll down.

3. Make sure that the PSU is functional and the green wire/pin on the PSU is shorted to GND.Replace if PSU is faulty

4.Check the controller itself if it is working by using another motor if you have one/ replace controller.

5. If the Motor spins up ok, but turns off after 3-4 minutes, scroll down.

6. Check your PSU to controller extension cable >> Step 6 (if used)

1. What to Do if your Controller is Fried/Smokes/Catches Fire:

Turn off the PSU immediately and give the controller a dousing in FRESH(non-saline) water, to extinguish any flames.

Next, You could either replace the controller from another HDD

OR

You could get a brushless ESC(Electronic Speed Controller), those used in R/C boats, aeroplanes etc. and attach it to your motor.

The + and - of your ESC should go to a 3.7v power supply, or according to the ESC's input specs. and the outputs to the respective motor terminals.The PWM terminals can also be attached to the same power adaptor if you don't want speed control.

Cheap ESCs available at HobbyKing.com / BannanaHobby.com(or any other R/C hobby website)

About ESCs you can PM me for more info. on how to attach them, etc.

5. What to Do if the Motor spins up OK, but turns off after 3-4 minutes:

There are a row of contacts on the HDD controller's PCB. These get connected to the actuator head. Some newer 'smart' HDD spin up, but once they realize that they have no parts, they again spin down. Fortunately my HDD for this instructable was dumb enough to keep spinning , if yours aren't you could:

Try shorting some of those aforementioned contacts. One of the contacts are bound to restart the HDD. If one does restart the motor, bridge it using solder to keep the motor running. If the controller goes up in smoke, use the mentioned solution below, using the brushless ESC.

OR

Keep the actuator head on and attached to the controller PCB

OR

Snip of the actual head and just keep the connector, if that works

OR

You could get a brushless ESC, those used in R/C boats, aeroplanes etc. and attach it to your motor, and remove the original controller completely.

The + and - of your ESC should go to a 3.7v power supply, or according to the ESC's input specs. and the outputs to the respective motor terminals.The PWM terminals can also be attached to the same power adaptor if you don't want speed control.

Cheap ESCs availible at HobbyKing.com / BannanaHobby.com(or any other R/C hobby website)

About ESCs you can PM me for more info. on how to attach them, etc.

An instructable is coming soon on how to use the Disk of Prometheus with a brushless ESC and with speed control. Subscribe to me for updates!!