I completed testing the prototypes yesterday and worked the kinks out of production. I ran 6 units in about 4 hours this morning and now I’m running 20 units over about 12 hours. Material cost is around $5 which makes it irrelevant considering that I don’t know who made the ball joints or where to get the plastic part that has failed. This should give me enough for now.
I do have 12 larger 19mm ball joints that have the same design. Regrettably I’ll need to fabricate the same part for them as well. Even when I reflect on the idea of spending a week making a part it’s still about as fast as ordering from Europe and I know exactly where to get the next replacement parts.
In the spirit of Open Source Hardware, here is the STL file to print the 16mm ball sockets. A couple of caveats. I redesigned the joint to have a ring that holds the ball captive. While the ABS can handle the insertion, it tears the socket apart when it is removed. The sockets cost me 15 cents to print, so I shrugged my shoulders. These should almost never be taken apart.
16mm-balljoint-r35 – for ABS
16mm-balljoint-r14-FINAL – for PLA
Yes, there are two different files. The PLA one is optimized for that plastic, the ABS one for that plastic. ABS shrinks when it’s printed which gummed up my entire design. PLA actually looked better and seemed to be fine with insertion/removal. It has a lower plasticity temperature and will go soft at 140 degrees Fahrenheit. I was concerned that the compartment that houses the generator could see that temperature. Sigh, PLA would probably have been fine, but ABS is a tougher plastic.