This model is a replacement part for Velux Venetian Blinds, which the manufacturer no longer stock or sell. The original runner/spring guide fell apart last year (likely due to 25 years of UV exposure) and so I took it upon myself to replace it. I used the remaining functional runner to get the key measurements.

The only parts from the original part are the spring tape and the centre wheel, both of which were in good condition in my case.

The model requires supports due to cantilevered areas and spans. The supports do take a bit of work to remove (needle nose pliers and a slim knife help!) and care needs to be taken around the hook area as this can be easily bent/broken.

After printing it needed a bit of light sanding in the side channel to get the fit between the runner guide and the spring holder correct. I have tested this print with Bambu PLA Basic and it works with no issues that I can tell. I'm not sure how it will hold up to long term UV exposure so it might be worth looking for a light coloured, more UV stable material than PLA.

Whilst this is quite a niche spare part, it is something that I couldn't find online so decided to share.