I redesigned the model which this was derived from including a much improved locking ring, a D shaft for the center piece, one piece end caps and reduced ability to pick. also it is scaled up about 120% because of the compete redesign the parts are not interchangeable with the original. I have only printed in PLA if you print in ABS please report how well the lock ring works. Print 5 letter rings of your choice (they only have half the alphabet) 5 spacers 5 ring 2's one inner tube one support tube one locking ring and as many shims as you need. ( i printed the whole set and only used 2) one "pins"Program by aligning the notch in ring 2 with your selected letter. to don't glue the pins on the inner tube until you have every thing assembled so you can find the best alignment. once printed i sand the sides of the ring 2, spacer rings and letter rings (ring 1s) to make it operate smoother. depending on how much you shim and how much you sand you may need to file the teeth of the pin to get everything to line up right. i had to on the orginal design but this one i did not. you can use a sharpy to color in the letters, then hit them with some white glue then color again for good sharp letters.