Introduction: Powerful Pocket Sized Rotary Tool

Picture of Powerful Pocket Sized Rotary Tool

I love my Dremel, but sometimes I wish it was smaller. I started looking around for a cheap, small rotary tool and found an oldDremel 7700-1/15 MultiPro Cordless at a garage sale for $8.00. Unfortunately, after about a month or two of use it the battery started to die. Rather than buy a new battery pack for it I decided to seize the opportunity and make an even smaller Dremel. At just over 4 inches it is about 2/3 of the length and the same width of the smallest rotary tool I could find online, the Dremel 754-04 4.8V MiniMite, and it provides 1.5 times more power.

Disclaimer: this could potentially destroy your rotary tool. I have only done this on the Dremel MultiPro Cordless, I don't know what will happen with other brands or tools.

Step 1: What You Need:

Picture of What You Need:

- Rotary tool
- Old rotary tool to cut up
- Whatever rotary tool heads you need to get the old tool apart
- Soldering Iron
- Solder
- Glue
- Electrical tape
- 2 neodymium magnets (optional)

- 9v battery snap
- 9v battery
- Voltage regulator (depends on the voltage your rotary tool requires)
- Switch
- Wire

Step 2: Taking Apart the Rotary Tool

Picture of Taking Apart the Rotary Tool

- Carefully break apart the old rotary tool to expose the motor and shaft that holds the bits; that is what we want
- Check the voltage required by the rotary tool; this will determine the voltage regulator you buy
- Purchase a voltage regulator that has an output close to the voltage required by your rotary tool; I got mine at Mouser Electronics

Step 3: Making the Circuit

Picture of Making the Circuit

- Solder the battery snap, voltage regulator, switch and motor together like in the picture
- Add the battery and test it out

Step 4: Finishing Up

Picture of Finishing Up

- Use a small amount of glue to hold the battery in place and tape around it
- Use a small amount of glue to hold the switch to the battery and tape around it

Adding the Magnets (Optional)
- Take the 2 magnets and place them on the sides of the motor
- Tape over the magnets
- You can use the magnets to hold spare bits


logorbit (author)2013-06-04


I am making a Rotary tool at home using a brushless motor and a pin vise, following is a build log.
Build Log - Homemade Rotary tool

Wareneutron (author)2012-12-27

i want a sample video of that?

M3G (author)Wareneutron2012-12-28

There you go.

Wareneutron (author)M3G2013-01-05

now i see that in action!
can i suggest? make a case for your rotary tool!!

svarbhe (author)2013-01-01

nice work.. friend , i want motor specification so that i can buy some equivalent spec. motor from local trader...

M3G (author)svarbhe2013-01-02

I'm sorry, I don't know the specifications apart from that it needs 7.2v an operates at
20 000rpm.

FrankenPC (author)2012-12-31

This is cool. The ubiquitous nature of the 9V battery is great. But, if I want endurance, I might try this with 2x LR123A lithium batteries. Gives you about 8V @ 2000mAh. They are about 1" tall. So they could be taped around the motor and not increase the length of the tool.

Cool idea. Thanks!

M3G (author)FrankenPC2012-12-31

Thanks for the suggestion! I might just have to get some lithium batteries now.

About This Instructable




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