Ever needed a mini rotary saw, but couldn’t lay your hands on the real thing? Well, a YouTuber has come up with a novel and quite cost-effective solution. Under the channel name MrGear, this clever problem-solver presents a step-by-step guide to making your own mini rotary saw. It’s not as effective as the genuine article, but in a pinch it should cope with light-duty work.

We’ve listed what you’ll need, as well as his steps from the video below. Watch the video above to see how MrGear created the mini rotary saw.

What you’ll need:

  • A 9 V battery
  • A snap-on battery connector
  • An on/off switch
  • One mini electric motor (the kind used toys and hobbies)
  • Two long, thin ice cream sticks
  • The metal cap from a cooldrink bottle
  • A nail
  • Insulation tape
  • The tube inside of a ballpoint pen that contains the ink
  • A hammer
  • A pair of scissors or pliers capable of cutting through the metal cap
  • A hot glue gun


How to make the mini rotary saw

Step 1: Snap the battery connector into place.

Step 2: Glue the switch to the side of the battery closest to the connector wires (see video above).

Step 3: Glue the motor to the bottom of the battery.

Step 4: Tape the ice cream sticks to the battery and motor for support.

Step 5: Slide the open end of the ballpoint pen ink tube over the motor’s axle (see video above). Cut off the tube to leave a clear section about 1,5 – 2 centimetres from the end.

Step 6: Hammer a nail through the centre of the bottle cap, then flatten the entire cap into a disc, using the hammer.

Step 7: Cut triangle-shaped notches around the edge of the cap to create “saw teeth”.

Step 8: Glue the now serrated bottle cap to the plastic pen tube (as in the video).

Step 9: Wrap the connector wires around the switch pins. Switch on.

Once everything has dried, your mini rotary saw is complete and ready to cut  through small pieces of wood and plastic.

Use caution when creating the tool as it will be very sharp. Ensure the serrated bottle cap is completely secure before switching it on, as the serrated edge is dangerous.

Video credit: MrGear