Magnetic Adjustable Rotating Arm/Ultimate Compass

Model Summary:

4/10/24: Added a base with mounting holes depending on use, Larger cylinder attachment for bigger flashlights/utensils, and the base with the set screw hole for the rotating cylinder. These updates are not documented in the instructions that are attached to this post.

This model was created to make a perfect circle since doing one free hand is not so easy. Highly adjustable with slides that allow your bolt to move freely down the rail. Tightening your bolts will be what locks all your pieces in place. The cylinder is press fit onto the base and freely rotates clockwise and counterclockwise once assembled. This model is mainly for drawing on metal surfaces but can be used for much more. That is why there is an option for a magnetic base along with attachments for marking with soap stone, sharpie, and a pencil. Attached are 3mf files that are setup for the bases, so the print stops allowing you to insert the magnets.

I have also been able to use this model to mount a small flashlight for my workspace! Comes in handy since this can rotate and moves up, down, and side to side. Just a little extra perk. 

Instructions for assembly and parts list are attached. Attached is the link for the recommended magnets. Cap screws can be found almost anywhere. 

1/2 x 1/8 Inch Strong Neodymium Rare Earth Disc Magnets N52 (24 Pack) for Sale | totalElement

Base Specific Information:

 On the base there is a cutout where you can put a ruler allowing you to measure from the center of your circle. There are 2 different size bases. 1 base is smaller so the jig can be used for smaller circles. The small base also only fits a ruler that is ½-inch-wide while the larger base fits a 1-inch-wide ruler. I recommend the large base when using 2 adjustable slides. You can use the edges of the hexagon to count by 60-degree increments when making your arc. The smallest hole the large base can make is a little over 3 inches and the largest the small base can make is a little over 2 inches. The maximum Diameter you can get is about 22 inches with 2 adjustable slides. This also varies depending on the utensil and number of adjustable slides you print. 

Printing Information:

I printed this model in transparent PETG. I preferred to do 3 perimeters and 25% infill for the base and rotating cylinder. The small and large bases are the only pieces I used supports for because of the ruler insert location. DO NOT do automatic supports for the magnetic bases because it will fill in your magnet pockets. The rest of the parts I did 3 perimeters with 15% infill. 

If you are looking for more information or have any questions, please reach out. If you are looking to have these further customized let me know and we will see what I can do for you!