SHARPENING MACHINE

FROM HARD DISK

To straighten small tools, drills and various parts, it is convenient to use a small sandpaper that you can hold in your hand. A variant of this design is shown in Fig. 1:

Rice. 1

It is advisable to take a hard drive “from the earliest days”, with a capacity of about 1 GB. It has more solid magnetic “pancakes”. The disk must be disassembled:

Remove the top cover;

Remove the magnets and head drive;

The extra pins are removed, leaving only the motor power supply.

Next, for testing, standard +5V, +12V power is supplied to the disk. The author used an ordinary AT format power supply. As a rule, at this time a pleasant surprise is discovered: in the absence of heads, the disk stops rotating after a few seconds.

You can combat this phenomenon in different ways:

Assemble a separate generator to power the engine;

Use short-term automatic interruption of the supply voltage;

When disassembling the disk, try not to remove all the heads (leave the bottom one);

Make adjustments to the existing engine power supply circuit.

Rice. 2

Unfortunately, it is impossible to provide a strict methodology for searching for characteristic points. If you can get it schematic diagram, then a lot of questions will disappear by themselves. The author searched using the classic random method. The general gist is this:

The microcircuit is determined - the motor driver;

Using an oscilloscope, the signal levels at its terminals are examined before and after stopping;

Signals similar to control signals are identified and studied.

The goal is to block the signal(s) that cause the engine to stop. In the author’s case, it turned out to be enough to unsolder a couple of transistors:

Rice.3

After long-term rotation has been ensured, you can cut a ring of the required size from a sheet of abrasive sandpaper. The ring is glued to the top disk with a few drops of glue around the circumference. The author used Moment glue.

When sharpening a tool, be sure to take into account the direction of rotation of the disk and position the tool blade in the direction of rotation. Otherwise, the skin will inevitably tear, which can lead to injury.

Files for the article

If you have an old one hard drive from your computer, don’t rush to throw it away, you can make a small handy sandpaper out of it! The motors in such devices almost never break, and we don’t need other parts. These motors are brushless, they develop high speeds and withstand heavy loads and durable.

An interesting homemade product in that you can use a special controller to control engine speed. This is very convenient if you need to process something very small. The author covered both discs on both sides with sandpaper, so they should last a long time. If the project interests you, I suggest you familiarize yourself with it in more detail.

Materials and tools used

List of materials:
– old hard drive;
– sandpaper;
– controller for the engine;
– connector for connecting the power supply;
– power supply 12V/6A;
– wires;
– materials for the body.

List of tools:
– screwdriver for unscrewing hard drive;
– soldering iron;
– 3D printer (optional);
- glue.

Emery making process:

Step one. Disassembling the hard drive
First you will need to disassemble the hard drive. The cover is in most cases secured with hex head screws. And on older versions there may be regular screws for the crosspiece. The screws can be quite tight, so without a good screwdriver they can be difficult to remove.

After removing the lid, remove the filter, this is a white bag, it is designed to collect the smallest dust particles. You also need to remove the write/read head of the hard drive. It is secured with one screw, and you will also need to remove two powerful neodymium magnets. We also remove the electronic board; we don’t need it, even if it’s working, it’s of little use. As a result, only the engine with the disks should remain.

Step two. Engine test run
The motor installed here is brushless, which means that it will not work if a constant or constant voltage is applied to its contacts. alternating voltage. Here you will need a special controller that generates a voltage of a special frequency, from which the engine runs. To start the engine you will need to buy a controller; you can order it from China. The controller is convenient because it has a speed control function. The device can be powered from a voltage of 9V to 12V.

We supply power to the controller, the green LED should light up, which will indicate that the controller is working. The disk is spinning, everything is fine, let's move on.

Step three. We cover the rims
We remove the disks; in most cases they are aluminum, but sometimes they are glass. The author glues sandpaper to them. You can glue the disks on both sides, then you won’t have to glue the paper often. You can simply rearrange or flip the disks. As a result, we get 4 working planes. If necessary, you can paste paper of different grain sizes. And if you have more discs, you can make yourself a good supply of sanding discs.

We install the disks back, it is not necessary to tighten all the screws, even 3 should hold normally, but for reliability it is better to tighten everything.

Step four. Installation of legs
Our machine will vibrate quite strongly at high speeds, and if nothing is done, the sandpaper will roll across the table. To solve this problem, the author screws rubber feet to the hard drive. They are quite common, you can order them from China, or you can make them yourself from rubber, and so on.

Step five. Housing and device assembly
The author has a plastic case, he printed it on a 3D printer. The case contains a controller, as well as a socket for connecting the power supply and a speed control knob. You can make such a case from plywood. The car screws the case to the hard drive with original screws.

Step six. Testing
That's all, the homemade product is ready, you can test it! The author's sandpaper easily sharpens a knife, and sparks even fly. The speed is conveniently adjustable, so it is not necessary to turn on the machine so that it works at the limit of its capabilities.

I hope you liked the homemade product, and now you won’t throw away your old hard drives. Good luck and creative inspiration if you decide to do this again, don’t forget to share your ideas and crafts with us!

Dec 7, 2018 Gennady

Hi all! Actually the idea is not new. They say the Internet is full of such records, I haven’t seen it yet, the idea appeared on its own. I had the urge to, you know, urgently sharpen a knife and a screwdriver... But “OH GOD!” The sandpaper is in the garage, but at work there isn’t even a file... Well, we are “sysadmins”, simple people, and I went into the “bins of the Motherland” and took out... An old hard drive from a PC...

We take scissors, screwdrivers, sandpaper, our HDD and double-sided tape

Everything we need.

Unscrew the bolts. The 7th bolt is always hidden under the sticker.

……………………………………………………………….

Let's open it. and everything is so beautifully packaged there. glitters.

We unscrew the head drive and the head movement lever, magnets for experiments, the rest can be scrapped.

Unscrew the disk mounting cover and remove the washer above the disk, as well as the disk itself

Place the disc on the sandpaper, trace the contours and cut out

These are the bagels you get)

We glue double-sided tape onto our disk (you can also add glue to it, but it will be easier to replace the sandpaper with tape)

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SPARK))))
Well, about the operation of this device.

It is better to use fine sandpaper; the engine is rather weak for coarse ones. But I had enough for sharpening everything I needed, even a lot. Bye everyone!