This story is not a good story, it is not a story that should have ever happened, it’s not one that should ever be told. This is a story about shaving a yak.(*)
It’s January 12th and I have a commission to make another Bulbasaur planter. I think that this is a good opportunity to document in detail the process that goes into 3D printing and cleaning up a sculptural object, for me process does not drastically change no matter what the project is.
For documenting the print I had it made. Dillon set up an aftermarket system attached to the 3D printer which allows us to, upload files, queue prints and control the printer from any locally networked machine in the house, thanks Dillon and thanks OctoPrint! In addition there is a feature on this web interface that allows us to time lapse 3D prints, so that was easy, taken care of. In fact I’ve already got the video.
But to capture the whole process, so i needed to record, well a lot more stuff, and to do that we have a go-pro! Ideally I will mount it to something and position near the work table…But the only mounts it came with were adhesive backed, for action sports helmets and similar use-cases. I’d like a more versatile solution then that.
Well attaching things to a tripod just requires some threads in the bottom right? What kind of threads…(we google it) a ¼-20!? That’s great I used tons of those I must have purchased hundreds of 1/4-20 nuts and bolts over the last year for projects at work. Let’s take a look around the house; oh, I don’t have any? I bought so many and miraculously didn’t pocket a single one and bring them home. Well shoot….
I guess we won’t resolve this tonight I mean all we need is a nut…
But we have taps. Taps thread stuff! What do we have to thread…well we don’t keep any billet aluminum around that’s for sure, Neither Dillon nor I have invested in the tools we need to do quality home machining. But I do have these huge offcut chunks of solid ¾” ABS.
And I know this is stupid, it should have never been done but I tell you what I did, punched a center hole traced a circle with a compass on the plastic. Then drilled the center with a #7, tapped it with a ¼”-20, then I cut it out on the band saw an cleaned it up on the bench sander and I’ll tell you what I wound up with it was a really ugly looking big plastic bushing with a threaded hole in the middle, and ya know what, it did exactly what it was intended to do, which was to bolt down to the tripod.
But that thing looked so stupid, and it was such a roundabout way to make a nut, the kind of thing that gets created in the fervor of the moment, where we get so consumed with ‘can we do things’ we forget to ask ‘should we do this’?
I did a quick design in Fusion 360 that incorporated a 1/4-20 nut, an object that costs <10 cents and was available at our local hardware store less than a mile away.
I quickly followed up with preparing the file for print on our Prusa I3 Mk3 using Slic3r. swore that first thing in the morning I would print something worlds better and go buy the bolt I was too stubborn to consider picking up the previous day.
The pentagon shape was great, based on the kind of hand-turn knob this shape ensured you had a great grip on the part (rather than the gopro) while screwing it into the tripod.
Unfortunately a print error and a design oversight left me with a cracked support and an unsightly glue blob on the bottom desperately trying to retain a bolt that could easily just fall out.
I had to design a better bolt retention system so I cooked up a model that captures the bolt inside of it and is retained by a snap-in clip that helps there be contact on all 6 sides of the bolt.
Below is a cross section without the top of the fixture in place.
Here is the prototype of the fixture:
It works great!!
Look at that retention clip fitment, I even shined a light up through the bottom to make sure that the retention tabs had slid into place. That thing is never coming out.
So with my first round of prototyping out of the way and a lot of damaged and sub-par solutions on the bench it was time for the next iteration.
New design Version 4, gives up on retaining the M5 bolt, there was simply not enough space available to make a strong enough print (with PLA filament), it integrates the clip retention for the 1/4-20 bolt. (Mixing SAE and Metric is a cardinal sin I know, but I prefer to work all metric and they standardized camera equipment)
Here’s how she looked after the support material was cleaned up it was all assembled:
The nut was firmly pressed into place captured inside the bottom of the part. I really like this clip-retention system, it was easy to design within the constraints of the part and it feels very secure, time will tell if we have issues with this design caming out and stripping all the surrounding plastic but for not it’s secure.
I admit that it really looks like the valve on a hose spigot. I really like that this mount allows you to maintain a solid grip on it while screwing in the captured bolt from the tripod. Traditionally I remember needing to hold tight to the technology, gripping a camera for dear life as you carefully thread the mounting plate onto the bottom.
Here we are finally performing the task it was designed to do!
Stay tuned for footage of future projects from slightly above and to the right of the work area. This is a great addition that I hope I’ll have ample opportunity to use.