Shelf Support - Extending Rod

thingiverse

This is an extending rod, designed in Fusion that can support bowing shelves (let me know if you can think of any other uses!) I've used it for (and designed it for) an old wardrobe that must have previously had too much weight placed on top, causing the centre to sag, interfering with/scraping the doors. It extends by rotating the centre rod, allowing the end pieces to screw further in, or out. This is done by using opposing threads on each end of the rod. The screws stay in placed based on friction with the shelves, so further improvements are necessary. The initial design is able to expand from around 25 cm to 30 cm, and is 30mm in diameter. If you were to expand it much further, the threading on each end piece may not be able to support the weight of what's above. Due to the nature of the design, the centre rod (when sliced with 20% infill, 0.2mm resolution) takes around 10 hours (overnight print, anyone?). However, even with this resolution, the threading still worked perfectly for me besides being slightly rough on the lower end-piece. Luckily, it's not too complex of a design if you're looking to design it yourself, just make sure to swap threads on either end. (Let me know in the comments if anyone needs it scaled down - it's quite a simple design thankfully, or has any improvements I could make - I'd like to find a way for both ends to expand equally, but haven't found a solution)