Hex spacers have always frustrated me. Indexing them, especially in tight places, is just a pain.
Inspired by Craftsman sockets, I had a student design a new type of easy use spacer.
We have been using this for two years and have been very happy with it.
Just change the scale in the z-axis to make any length you need.
What about just (pre-)printing some of them as long as your printer will allow and then cutting off lengths as needed? No need to wait for custom length printed on-demand.
Curious what the benefits to these are over just a cylinder with a ~15mm ID and some arbitrary OD? Is there a reason you need your hex spacers to not potentially spin on a shaft?
Often spacers are adjacent to gears or bearings or other things which are rotating with the hex shaft. So if the spacer rotates along with everything else then there is less friction/heat. That’s a good thing.
If the spacer is installed correctly, every surface the spacer is in contact with will be rotating. That means the spacer will rotate with the shaft even if there’s no intentional torque transfer features in the spacer.
I can see a case where a loose round spacer rubs against a bearing outer race, compared to this design which would remain in contact with the inner race.
I like the idea of scaling the part in the Z to set the length. Very clever!