The printed x-axis idler on my Prusa-Mendel was very much in the final stages of its life, It was held together with cable ties and fencing wire. Last weekend it finally surrendered and broke completely. So it was time for some repairs and maintenance.

Fortunately I had a replacement part on standby - without a doubt, one of the best things about the reprap movement is the ability to repair itself. I am getting to the stage where I like to have a few spare parts on standby. Pulleys, belt clamps and anything else that might be looking a little sad. When something does wear out, swap out the broken part and back to printing.

I was also not very happy with the printed couplings I was using. So a while ago, I picked up two 5mm to 8mm flexible shaft couplers from ebay. I was waiting for x-axis or the existing printed couplings to go before installing them, so had a crack at putting those in on the weekend as well.

Really happy with the way the aluminium couplers turned out, however when installing I noticed that the 5mm (motor shaft side) end fitted better than the 8mm (threaded rod side). I had to squeeze the hell out of the 8mm side to get a decent grip on the threaded rod. I figure this was because only the outside of the thread is 8mm, and so didn’t provide much surface area for the coupler to grip onto the rod. Next time I might wind a layer of electrical tape onto the threaded rod before installing the coupler.

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