OO HO Magnetic Pipe Couplings for NEM Socket 3D print model

I launched these back in 2023 and many people have purchased them, personally most of my rolling stock now uses them. I have found them very reliable and the magnets work very well. The ABS like resin is definately recommend for these when printing.

In 2023 I bought some Hornby Magnetic couplings for my Hornby MK2F coaches but they were not long enough, I was very impressed with the magnetic strength of these couplings on other rolling stock. I tried some Kadee couplings but the sag in the couplings was causing issues going over points etc. I looked at Hunt Couplings but wasn't that happy with the look of the coupling and wasn't sure how they would couple to my Hornby Magnetic couplings. This was beginning to frustrate me so I finally decided to see if I could develop a similar coupling to the Hornby Magnetic coupling that I could print and install magnets. I found 2mm x 1mm round magnets on eBay for about £4.50 (50 off) and I started to develop a coupling.

My biggest concern with this was the strength of a resin for something like a coupling, so the design was kept fairly simple to maximize the strength. I printed my first set with AnyCubic black resin and installed magnets, I made a few modifications before testing a whole rake of 6 coaches on a model layout. After about 2 hours of testing I had no failures and the performance was really good. I then bought some AnyCubic ABS-like resin which proved to be better than the standard resin.

Magnets used:

https://amzn.to/3WZoThF (Amazon) Associate Link

Resin used:

AnyCubic ABS Like Resin Pro 2 https://amzn.to/4dVZoEU (Amazon) Associate Link

Please be aware that 3D printed couplings will not be as strong as injected molded couplings, with using these you will probably need spares on hand in case of any break. With the ABS-like resin I have had minimal failures but nothing is perfect.

I have included a range of sizes as different rolling stock need different lengths (Please message me if you would like other sizes). Files with 75 are 7.5mm, 85 are 8.5mm, 100 are 10mm and 115 are 11.5mm (Distances are measured from NEM socket to Magnet Face - see pictures).Magnets need to be glued in and you need to have the correct magnetic polarity for each magnet. This is very important for coupling together.The examples in the pictures were printed on an AnyCubic Proton M3 3D resin printer.For dimensional accuracy, I would recommend printing on a resin printer.As mentioned I used AnyCubic ABS Like Resin, I’m not an expert on what resin you should use.

Additional Info

Please check out my Website, https://sites.google.com/view/pete3dprintinghelp/home

My website has lots of useful info.