Alternate Collet Design and Extended Threaded Slider For Hadley

prusaprinters

I was inspired to make these models based on ballanux's Non-rotating helical focuser and Max's compatible locking nut. There were a few considerations that led to my design choices, the first of which deals with tolerances. I'm not sure if my printer is calibrated very tightly(Pressure advance, input shaping, material shrinkage compensation), or maybe it even under-extrudes after all these steps, but even with the tightest tolerance models available from ballanux's post, I still had considerable play in the both the threads and retention ring(the one that's glued in), causing wobble in my setup.My first modification was for the retention ring, which I used offset face to remove its tolerance gaps. This made the focuser ring fit much better with my base, luckily I was able to crack apart the superglue from the original attempt to reuse parts :)To address the thread tolerances I created a new threaded tube using the written specification of M56x5.5 thread (it does matter! lol). I tightened up the tolerances on the rail slots too since I had to model those in anyways (make sure to print a short section of 3-4 threads to test fit, it's very tight). I also made the tube 9mm longer to restore the focus length otherwise lost from Max's locking nut. Feel free to request modified versions and I'll try to accommodate with future updates. (Purple is original parts, pink is new part)My biggest change to this project is the modified collet design, using a more gradual taper that squeezes evenly from all sides along the full length of the collet. I noticed a polished ring worn into my printed collimating eyepiece from spinning it in the collet, this made me realize the original design concentrated pressure in a ring, which could also introduce some wobble. I took inspiration from precision metal collets to model a design with a similar zig-zag cut so the collet tightens over the entire length. Since the taper is so gradual, I provided a few different heights for the collets in 1.5mm increments to accommodate any XY tolerance variance.I added chamfers to combat elephant's foot during the print as well, but be sure to inspect the parts for artifacts that may interfere with alignment. One tip is to print this collet sleeve in a different layer height than the threaded tube so the layers don't mesh together and they will slide past each other better (solvent smoothing or light&EVEN sanding could help too if needed). Please let me know your thoughts in the comments, I'd love to hear if it helps others out!--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------Edit 11/21/2022: Folder with extra tolerance parts added. The blue surfaces have had the adjustment, only the slots and outer diameter.----------------------------------------------------------------------------------------------------------------Edit 1/16/2023: Extra tolerance parts for the collet's inner diameter have been added to address the collet grabbing the eyepiece during insertion before the ring has been tightened. Again, the blue surfaces show where the tolerance has been added.