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 old Dremel 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.

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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
Screen Shot 2012-12-22 at 11.jpg
- 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
logorbit2 years ago

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
Wareneutron2 years ago
i want a sample video of that?
M3G (author)  Wareneutron2 years ago
There you go.
Wareneutron M3G2 years ago
now i see that in action!
can i suggest? make a case for your rotary tool!!
svarbhe2 years ago
nice work.. friend , i want motor specification so that i can buy some equivalent spec. motor from local trader...
M3G (author)  svarbhe2 years ago
I'm sorry, I don't know the specifications apart from that it needs 7.2v an operates at
20 000rpm.
FrankenPC2 years ago
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)  FrankenPC2 years ago
Thanks for the suggestion! I might just have to get some lithium batteries now.