DIY Brushless Dremel Tool

Its been almost two years as I got my first batch of cordless tools, most of them were brushless so love the amount of power these tools offer.

With me scratching my head about what to built next I had an idea to built a brushless Dremel tool thats powered by those high capacity lithium ion batteries.

Well the idea sounds good but the challenge it to make that brushless Dremel tool without throwing a lot of money on parts and making the whole project as easy as possible.

So the goal is to built a brushless Dremel tool out of scratch. So get through this intractable in which I am going to show you how to make a Brushless Dremel Tool under just 15$.

Lets get building…

The list of materials for this project is:

• A 12v High speed server/pc fan (The one with current draw above 1.8Amps)
• Drillpro Adapter kit
• PVC fitting and pipe
• 18650 lithium ion cells
• Wires
• Switch and socket
• Spray paints
• Glue

The list of tools recommended for this project is:

• Handsaw
• Drill machine
• Drill bits
• Soldering tools
• etc

Now the first challenge is to find a brushless motor. There are two types of brushless motors, inrunner and an out runner motors. The term in and out refers to the position of the magnetic rotor in the motor. The one that we are going top need is an out runner motor due to the larger amount of torque it produces as it has a large moment arm as compared to the in runner type of the same size.

As compared to the conventional DC motors these Brushless motors needs an ESC to run them. So we need to avoid all those complexities and for that I decided to use a Brushless motor from a high speed server/PC fan. You can easily recognise these fans by the higher amount of current draw as stated on the rear side of these fans. These fans comes fitted with an ESC so all you need to run the fan is to connect it to a 12v battery. But be careful as they can cause serious injuries if not handled properly.

Now what we need to do is to get that brushless motor out so I broke the casing and the fan attached to the motor.

By now we have a brushless motor but we need to attach an adapter for holding the appropriate bit to get the job done. For that we need to replace the existing shaft with a longer one. So I removed the clip from the rear side of the motor shaft to take off the magnetic rotor. The shaft is push fitted inside the motor bell. SO to remove it we need to hammer it using a nail.

The shaft measures nearly 3mm in diameter and we managed to find a shaft with same diameter from an old CD rom with our desired length. So we push fitted the new shaft with a Hamer. For the adapter I am going to use a Drillpro Adapter kit ideally made for application for making Dremel tool.

Now to hold the motor I am going to use a 1in dia PVC socket with 45 degree angle. Not only it fits the motor rear side perfectly with a minor sanding but it also makes working with the tool much more ergonomic.

First I sanded the motor rear plastic housing and then glued it to the PVC socket. Next I have extended the wire and removed all the unnecessary wire. The red wire is VCC and the black one is ground.

Now to power this tool we are going to make the battery pack using three 18650 lithium ion cells. I salvaged these cells from an old laptop battery, they were holding identical voltage above 3.7v so I expect them to work porperly.

All the three cells were soldered in series with a pair of wires connected on both the positive and negative battery terminal. Out of which one wii then be connected directly to the charging socket which is a 5mm input jack.While the other pair goes to the motor through a toggle switch which is going be used to turn the motor on and off.

Now to make everything simple I haven't added a protection circuit after the battery which will stop the battery from draining below its minimum voltage but you can do that by adding three tp-4056 modules along with the battery pack to do the job and increase the reliability of the battery pack.

Now to mount the battery and built an enclosure we are going to use a 3 inch PVC pipe and cut it short to make it fit perfectly to the battery pack. The battery is first glued to the PVC socket/motor mount and then I clipped the PVC pipe using two jubilee clips and the glued the PVC pipe to make it hold the shape.Once the glue dried I removed the clips and sanded it to make it look perfect.

Now to give this tool a neat look I decided to paint the enclosure using a matt black and a yellow spray paint. I masked the motor, switch and the charging socket. The enclosure is then painted and the finish went really good on that one.

As the paint dried I have removed the masking and the finish was well worth the work. That mini handful brushless Dremel tool went above our expectations and performed really well. At first I was a bit worried about the power of this motor as these kind of motors are not meant I mean they are absolutely not meant for the purpose that we are using them but they performed really well. The torque is fair enough to grind through metal and can handle the largest 2.5mm drilling bit that can fit inside this adapter.

As far as the efficiency is concerned the motor seems to do the job pretty well and the battery pack is large enough to run the tool for quiet long before we run out of battery.

Overall the project ended us adding another useful cordless and Yes Brushless Dremel tool without breaking the bank.

For more interesting DIY projects visit my youtube channel.

Regards.

DIY King