Years ago the cap that came with my X-acto Gripster knife cracked and wouldn’t stay on the knife while it was stored in my drawer making a safety hazard. I finally got around to making a replacement cap. Version 1.0 worked but had a strange kink in the side and had to be trimmed to remove elephant’s foot on the inside of the opening to fit the knife.

Version 2.0 is designed to be printed the other way (top) down on the print bed. This alleviated the elephant’s foot on the opening and had the positive side effect of placing it on the top of the cap where it aids gripping the cap. I shortened the length of the cap because it was clear it didn’t need to be as long and this saved some material. I also placed a fillet where the cap widens for the handle of the knife for aesthetics and to make sure that I don’t need supports when I print it. NOTE: you must flip it in Cura or whatever slicer you are using. I designed it bottom down, but it must be printed top down.

The design is completely parametric, so if you have a different knife, just input the correct measurements. Note also, the parameter PressFitTolerance. I use a series of 5 global parameters for tolerance. This one could also be called snap fit. Gravity will NOT remove the cap, but very light finger force will. This tolerance value varies by printer. Mine is a Snapmaker A350T. If you aren’t sure what that value should be for your printer, see this YOUT video: https://youtu.be/Re4tKegVfqs which guides you through making your own tolerance test block. This is a great exercise in understand tolerances and just how exact your 3DP is printing.