Cannon (Gravitrax compatible)

Overview

Custom cannon for round 10mm neodym magnets, compatible with Gravitrax.

The groves and little "ears" are there to make it easier to remove the marbles with your fingers. It works quite well and needs less force than with the original Gravitrax Cannon.

Magnet size selection

The magnet size determines strength of the gauss cannon. My initial design used 10mm magnets and resulted in a really strong cannon which was not easy to handle. It needed careful track design in order to work reliably and not destroy the track or throw the marbles off-course.

I ordered 3mm magnets at eBay which ended up being 2.7mm and not as strong as anticipated, so I put two of them together, resulting in a 5.4mm magnet. This resulted in a cannon which has a similar strength as the original Gravitrax one. Neodym magnets come in various qualities and you don't always get what you order, so your mileage can vary and you might need to experiment a bit.

Contents

The archive includes STL files for the following magnet lengths

• 3.0mm
• 3.5mm
• 4.0mm
• 4.5mm
• 5.0mm
• 5.5mm
• 6.0mm
• 8.0mm
• 10.0mm

All of them expect a magnet diameter of 10mm.

Additionally, there bottom part prints separately and needs to be glued in after printing. This way, no supports are needed.

Print Settings

Printer Brand:

Anycubic

Printer: 

All-metal Mega

Rafts:

No

Supports: 

No

Resolution:

0.15

Infill: 

15%

Filament: Generic PLA Black

Notes:

Turn off supports.

For the bi-color effect as in the image, tell your slicer to change filament at the layer right after the main plateau. It might help to add some small dummy object next to your print and make sure that the dummy is always printed first on every layer. This way you can ensure that the nozzle pressure is fine and the nozzle is wiped after changing the filament.

Post-Printing

Add bottom part

Use your favorite plastic glue and add the bottom part. The more conical part goes into the bottom of the actual gauss cannon.

Add magnet

The magnet needs to be 10mm in diameter and you should be able to snap it in with moderate force. If it doesn't work right away, you can try to heat up the magnet holder a little bit.

Category: Toys & Games