A loading breech I created in Inventor for a future project. I was inspired by the russian 122 mm M1910 howitzer's breech and sought to create a design that is 3d printer friendly. This is the result, taking into account 3d printer tolerances.

Prusa

Prusa Clone

No

No

.1

15%

Make sure to tune your slicing settings and level your bed as finely as possible for this to work.

To use the breech, place the male part into the female part on the side with arrows, making sure the vertical lines on both of the parts align. Then, twist in the direction of the arrow.

First of all, I designed this part in Autodesk Inventor using the thread function and then an addon called CoolOrange thread modeler. Once I applied CoolOrange onto the thread, I then combined all solid bodies in the part (CoolOrange creates a separate body for the thread) and then cut away 2 grooves in the threads. Then, I got rid of all sharp edges using chamfers and the extrude tool since sharp edges usually turn into bulges when 3d printed.

Then, In MeshMixer, I oriented the part correctly and scaled the receiver by 2%. This 2% accounts for the the tolerance of the 3d printer, allowing for the part to fit correctly after printing without any need for post processing.