Modular Rostock delta push rods for a larger-than-standard Rostock build. I needed 300mm center-to-center but only had a 6" (150mm) print area to work with.

Each segment adds 100mm to the total rod length; you'll probably want to double-check the actual length, adjust, and re-tighten connecting screws for best results. I used M3x10, but M3x12 would have been better.

These could be extended to 400mm or 500mm, but mine are already a bit more flexible than I'd like and will eventually be replaced with carbon fiber tubes & Traxxas 1942 ball connectors. Nevertheless, maybe someone will find this useful.

This design is a derivative of Asger's half-rods, itself a derivative of a half-rod design by sivar2311. The 'Mid' rod should be fully compatible with either of those designs if you need to extend them to about 350mm.

Using only the 'End' parts will net you a 200mm rod; one 'mid' part will achieve 300mm, and two should end up at 400mm. These are measured center-to-center your firmware will expect (I use Marlin) for DELTA_DIAGONAL_ROD in configuration.h (or equivalent), total length will be longer.

This results in 12x 'End' rods and 6x 'Mid' rods for a 300mm delta configuration. I managed to print all 18 parts in exactly two batches on a 150mmx150mm (heated) bed with ABS at 0.3mm, but it's probably better to use 0.2mm if you can.

Rods were fastened with M3x10mm machine screws; some have washers, some don't, and I wasn't consistent between lock nuts and standard ones. So far, every combination has held up fine, but I'll (probably?) update this with better information after I've used these for a while. Note that M3x12mm would have been better, especially if using washers and/or lock nuts.

If you're building a standard Rostock without changing any dimensions, these are not going to work. The 200mm configuration might work with a 'Rostock mini' build (albeit with reduced build height), but you'll definitely need to change the rod lengths in firmware.