Steve, I modified some of the gears to add heat set inserts. This made it easier to lock them down to the arbors. I can send those to you or you could think about including them. I made the hole 4.1 mm in diameter and added some width to the shaft on a few to make stronger
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Looks good. What heat set inserts did you use? Would it be something like these?
150 Pcs M3 Threaded Inserts, Brass Knurled 3D Printing Nuts, Embedment Twill Brass Thread Screws Heat Set, Thread Knurled Heat Brass Nut for 3D Printing, Automotive Plastic Shells - M3*4.6x5.7 mm: Amazon.com: Industrial & Scientific