Simple circle cutter

Since I couldn't find a circular cutter that suited my needs, I decided to make my own. The main goal was to create a circular cutter that would be used to cut circular holes as accurately as possible in technical materials such as rubber, certain types of insulation, and so on. I needed to to the exact circle into phone cover and I need to invent something for that, so this idea came to me. Before cutting, it is necessary to first make a 5 mm diameter hole (e.g., with a drill). Then, loosen the screw (red) and set the distance (the radius of the circle you want to cut). The cutter can be used to make holes from approximately 56 mm to 210 mm.

What do you need do assemble the cutter:

• First of all print the parts from printprofile
• Second – see the picture below

Step by step instructions for assembling the cutter:

Insert the M3 threaded inserts with some heat source.

Into the inner slider and RED NUT insert M5 nuts all the way down. 

Insert the completed inner slider into the cutter body as shown in the picture.

Use part M5 of the screw as shown in the figure above and screw it into the inner slider from the bottom of the cutter body.

Screw the screw in until it reaches the end of the thread.

In this step, attach the top slider onto the M5 screw.

Then screw the red nut onto the upper slider.

Then insert the headless screws or any screws into the threaded inserts. The minimum thread length should be approximately 7 mm.

The screws should not be screwed in completely.

Insert one piece of the utility knife blade into the hole in the cutter body. Max width should be approximately 9mm.

Pay attention to the direction of the blade's bevel. The position of the knife will determine which way you will need to turn the cutter.

Manually adjust the cutting depth by moving the knife blade up and down, and then tighten the screws.

The knife is now ready for use.

Loosen the sliders by turning the red screw counterclockwise (for standard nut thread winding), set the distance and thus the radius of the circle, and secure the red screw in the desired position by turning it clockwise. Then insert the cutter rod into the prepared hole, ideally 5 mm for the most accurate results, and start cutting. For optimal results, I recommend placing a piece of wood or other solid and stable material under the material being cut.

The assembled tool contains sharp parts and you may injure yourself. Use at your own risk. 

If you are cutting thinner material and the blade protrudes slightly from the cutter body, be careful because the upper part of the blade is also sharp and you may cut yourself.