So, the faux leather shift knob on my 2013 Kia Sou decided it wanted to be faux suede instead.
So I've decided to see if I can 3D print a replacement that does any better. I have some rather grandiose ideas in mind, but I think I'm going to start with a simple 60 mm ball. I don't really like Freecad, but it has two things going for it: It's free, and it isn't OpenSCAD. And for a simple sphere with a few counterbores, it should be adequate:
This one is just a very plain sphere, no shift pattern or decorations. But you can see there's a deep counterbore to clear the reverse lockout. The thread is an M10 x 1.25. This knob might fit other Kias.
Loading it into the Prusa slicer:
I'm doing a low infill print as proof of concept to see how I like the fitment and ergonomics. After that, I have some ideas for more over the top designs. I'll post an update when the printer finishes.
Nice work. I'm always amazed that we live in an age where we can design something on a computer in the morning and have it printed by the evening.
I was designing in Blender for a long time (software is fine, but not ideal for CAD for a number of reasons). I recently spent some time learning Fusion 360 and it's much better. There is a free version for personal use.
I mean feel free to print one, but I really like delrin and you can easily search for them on evilbay. I've had the same delrin shift knob in my Hondas for a decade+
I have also given some thought to drilling and tapping a pool ball - I might go with a four ball instead of the traditional eight ball, since I only have four cylinders.
But playing around with a 3D printer lets me experiment with different sizes and shapes, and see what I like. And I have some more over the top ideas I want to try.
I did a knob for my sprite awhile back. I had some knotty wood and got a wood lathe attachment for my drill press. After shaping I coated it in polyurethane. Didn't quite get the shape right in my first go, so it's not the one in use in the car, but it looked pretty awesome. Should try again.
My mustang has a billet aluminum ball knob, it's pretty cool, but that said, I have just about branded my hand on it when the cars been parked in the sun.
One thing you might play with is weight, it plays a big factor to functional feel.
Apexcarver said:
My mustang has a billet aluminum ball knob, it's pretty cool, but that said, I have just about branded my hand on it when the cars been parked in the sun.
My brother had the same problem with his billet shift knob, so I got him a little hat.
In reply to Apexcarver :
Go to the dollar store and buy a pair of baby socks. you won't brand your hand , or freeze it in the winter.
Yup, did that a long time ago.
Also, a recent tool purchase might have me making a new knob for my bugeye when I get the 5 speed swap done. 
A lathe would definitely be faster than this printer and get a better looking result. Took me 4 hours for the first one to print.
Well, this is annoying: Turns out that while FreeCAD can export STLs with properly threaded holes, you need to check a couple boxes that I missed the first time around. So I spent four hours printing a part that wouldn't thread on.
Here are the boxes, for you to follow along. Yes, you select a thread profile but have to select "threaded" separately.
My wife really did not like having to listen to the printer for four hours. So I have one of the "silent board" 32 bit upgrade kits on order to see if that hushes up the printer servos.
It will quiet the servos but the fan will still be noisy. Then you get the fan kit... it's a whole rabbit hole.
fwiw OE knobs are cheap. I used a leftover knob from my veloster in my soul.
Sure, I could just throw a shift knob from some other Kia / Hyundai product on there or order some sort of universal aftermarket knob from the usual places. But where's the fun in that? 
Oddly, OE Soul shift knobs seem to be pretty tough to find. Any dealer who does have any leftover stock wants over $100 for one. Veloster six speed shift knobs are less than half that.
What thread pitch does it use?
I've turned several knobs for my Corvettes. It took me a few tries before I found exactly the size and shape I wanted, but it's been quite rewarding.
brandonsmash said:
What thread pitch does it use?
I've turned several knobs for my Corvettes. It took me a few tries before I found exactly the size and shape I wanted, but it's been quite rewarding.
I think it's M10 x 1.25, according to the interwebs. If the first knob had printed with threads, I'd know for sure.
Well, this is really annoying. Here is what a Creality 4.2.7 board should look like.
Here is what I received.
No Creality logo or version number, and a different board layout - note the switch near the bottom row of connectors, an extra connector behind the SD card, and the trim pots next to the servo drives at the top are on the opposite side. And also, the board doesn't work.
I bought it on Amazon, and they are (intentionally?) tough to tell how I would have ended up with the wrong board. Amazon tends to mix inventory from different sellers, and it is also possible somebody bought a real one, returned a fake, and it got put back on the shelf with nobody checking. I am setting up a return and I hope I'll get a real one next time...
Put the original board back in the printer to run this one:
It could probably use a slightly longer thread and a wider cutout for the shift lockout mechanism, but everything's working. With 100% infill, the weight is about right too. This is a 55 mm ball, in between a pool ball and a snooker ball. Next steps will be some more creative ones now that I have a good idea for what size I want.
Some "living with" notes - the knob tends to loosen a bit in heat. I may try using some adhesive on the next one I print.
Why not use a steel insert instead of putting threads directly in the plastic?
prodarwin said:
Why not use a steel insert instead of putting threads directly in the plastic?
I'm considering it, but trying to see how far I can get with minimal effort first.
So, JB weld is pretty sturdy and can be tapped. Just saying...
Apexcarver said:
So, JB weld is pretty sturdy and can be tapped. Just saying...
Probably not needed. The threads seem sturdy enough, just aren't self locking.
PLA will soften and sag in a car sitting in the sun (even in places that aren't particularly hot!)PETG is really the minimum material spec...
The PETG phone mount I made for my car is comically deformed after less than a week.
It's been in the car over a week, outside temperature hitting triple digits, and the worst I can say about the PLA is it's not impersonating Nyloc nuts. This is better than expected. It was printed at 100% infill though.
