Mariah’s multicolor pen broke. I didn’t have any prior experience doing 3D modeling so I figured I’d take the opportunity to start learning CAD (I needed to anyhow if I ever hope to get any use out of a 3D printer). My goal was to get a new pen machined in aluminum but it seems like that might be prohibitively expensive given that it’s a one-off design with some fiddly parts.

Here’s the original pen:

I’ve modeled all that I can without breaking the pen and that’s landed me here:

After talking with some machinist folks, it seems like I’d be best off rounding out the slots that the selectors slide in since it’s hard to get square cuts on either a lathe or mill. If it were important to maintain a square profile for the slots, I could take a coping saw to square out the circular ends that a mill would leave. It also sounds like the curving nature of the writing end of the pen will probably cause problems, especially the fact that it curves on the inside.

At this point, I need to model the reset button and the hole it goes through and then, I’m going to see if I can thicken up walls so that I can try printing this to see if that’ll cut it (I don’t expect that 3D printing it will be satisfactory given the size of the design).

Anyhow, it’s been a fun project so far. I think I’ve learned a lot so far about modeling and I’m looking forward to my next modeling project (hopefully a case for a keyboard).