Ring Nut Wrench

Plastic ring nuts are used in a number of applications. They are commonly used to hold fuel pumps into fuel tanks. Normal tools have trouble removing them.

I had this problem with the the fuel pump ring nut of a Mazda RX-8 so I designed this tool to get it off/on. Commercial tools for this job are about $70, so I hoped a homemade tool could get the job done just as well (if not better).

The tool works well. Using wood and mild steel plate I added a 1/2" drive to it. I think this usage is well within the strength limits of PLA.

Your ring nut may well be different. The design is parameteric so you can adapt it to meet your needs. I've included the source if you wish to modify it.

Update (Feb 13th 2022): The original wrench was keyed to a particular direction because of the extra tab on the ring. It's useful to reorient the tool while it's being used, so I have added extra tabs on the tool. Now it can be positioned at any 10 degree increment.

Note: This is not OpenSCAD. It's a program written in Go. The main library and code examples can be found here:

https://github.com/deadsy/sdfx

About Go: https://golang.org/