Background:
My office door has a rather old Kwickset doorknob which recently broke. I immediately opened it up and found the plastic core had cracked so I ran to fusion 360 and managed to recreate the original core.
I beefed up the walls for increased strength and use calipers to get the measurements as close as possible. Why spend $20 on a new doorknob set when I can fix the one I have.
When printing I printed in flat side down with standard tree supports in Bambu Studios. The holes will come out a bit oval but everything should fit regardless.
The pictures shown are printed in PLA. To not waste more plastic I will be using that original print until it breaks. I would recommend you printing this is ASA or ABS.
Usage:
This uses the original hardware except for the pin which I had to cut. So I replaced the pin with an M2 machine screw. Unfortunately for me I only had a 20mm and had to tape the head in place. But 22-25mm should be perfect depending on the diameter of your doors hole.
I also reused the original plate that goes against the lock.
Hardware:
The author marked this model as their own original creation.