This post took a bit longer to get done because I took a bit longer to do it. Wait, that wasn’t helpful. Anyway, I tried something I was pretty sure wouldn’t work and didn’t. I hate being right all the time. Then, in spite of being tired, I rushed to get something simple together and that did work, well, sort of but not really. Then I had to go to work, well, with everything the way it is I don’t go to work I log into work but the point is I had to actually do things for the people that pay me so I couldn’t work on this. I feel like they can be so unreasonable at times, there’s a global pandemic after all!
Folly – What not to do
I finally got back to working on the clamp part of the Webcam Positioner. I initially thought I’d do the simple thing, a couple of plates with a screw between them and a mount point for one of my ball joints. But then I thought, that’s too easy and possibly successful. I’ve been doing this for almost 2 weeks now, it’s time to try something challenging so …
Yup, that. The idea was that the cog would be turned and move the slotted bar back and forth. One end would be attached to one side of whatever this is to clamp to and the other side to the part with the cog. This was supposed to be a prototype I planned to keep on my desk and move back and forth when I was bored or the voices in my head got really loud (fidgeting with things helps when that happens.) The flat piece was printed separately, I forced it under the cog for the picture, but the stand, axle, and cog are all one print and it almost worked.
It’s small and I think if I made it bigger it might have worked. There was a ridiculous amount of support structure because, well there were a lot of parts that needed support, and it was a bear getting it all out because of how small the print was. I need to start making my prints bigger, I think things would work better if I did, more leeway if something off a little. A piece of advice, if you don’t need holes in something vertical, don’t put holes in there because then support will need to be printed to fill the holes because they are basically meeting overhangs. Or print it flat and put it together afterward.
I was hopeful at the time. Unfortunately, after I pulled away all the support structure and tried to free the axle with a hard twist all that happened was the plastic started to tear and stretch. That PETG is really tough and flexible. \
I have an idea to get around that problem I may try later, but I spent a lot more time on this than I should have given I thought it wouldn’t work, and it’s an overly complicated design for a really simple task, so I’m moving on to a more pedestrian design.
Pedestrians can suck
So, I was tired when I started working on this. That’s not intended as an excuse, it’s intended as advice, don’t work on things if you’re tired, you don’t think them through and end up with something like this.
I know it looks like it’s clamping, I guess it is, but it’s barely holding on and wouldn’t hold any weight. You can see how the part on the left is angled out some. Basically, it’s using the edge of the shelf as a pivot point and the more I tighten it down the more it bends. And then this.
Yup, the head broke off the bolt. It’s easy enough to fix. I printed another one and had the first 40 or so layers be through and through which was a lot tougher. The second bolt broke too but in the middle where I had 20% fill specified. I’m not sure why exactly, maybe too much pulling force caused a layer failure. I successfully glued both bolts together though with Gorilla Glue super glue. They’re not going to keep the bumper on my 1973 AMC Pacer, but I might be able to find something to do with them. Otherwise, I’ll send them to the island of failed prints and ideas with the other failures I’ve had.
Think before you act
I realized that the problem with this simple design was that as the screw tightened it caused the parts intended to grasp to pivot where they came in contact with the thing they were supposed to clamp down on. One way to avoid this is to move the pivot point behind the tightening screw so it forces the grasping parts into the thing to clamp to. So I modified my design a bit to add an adjustable screw behind (farther away from the rasping hands) to provide a pivot point there. I also chose not use a ridiculously large wing nut.
I reduced the bolt size from 12mm diameter to 10mm diameter. With the smaller rings and using a 40% fill rate instead of a 20% fill rate, I’m hoping that the lateral strength will be better than the larger more hollow bolt. I also removed the wide head and the one bold threads into the plate instead. I still have a bolt with a connector at the end but it’s longer. If it breaks I have some ideas on how to improve the strength, hopefully, it won’t.
To make the pivot point adjustable, the lower plate is threaded and a mostly straight bolt with a hex end to adjust it screws through from the bottom. The other end fits into a recess in the top plate so it doesn’t slide around.
The tightening bolt is toward the clamp arms side. It threads into the upper plate and a nut is used to squeeze the plates together. As long as the first bolt is at the right height, it will act as the pivot and the arms of the clamp will get tight on whatever they are around. A simple design used for a long time by anyone needing to clamp things. I have an old machinists clamp from my father that works a lot like this. Anyway, here’s the final working clamp/mount.
Although the clamp did clamp, PETG is pretty smooth and slippery. I took some vet-wrap, which is not, and glued it to the clamp to give it a little more sticking power. Most stuff doesn’t glue PETG well but Gorilla Glue super glue seems to.
You may have noticed the little Bernie Sanders helping with the pictures of the clamp. I saw the file for it on Thingiverse and thought my wife would like it, so I printed one for her. It’s tiny, so scaled it up and printed it for her. The tiny Bernie sits on her sewing machine and big Bernie watches from the sidelines. This is the fun, as in silly do it for fun, side of 3D printing I should probably do more of.
The hole truth
The first print looked good and I thought I nailed it, and I did as far as the clamping mechanism is concerned. Well, nailed it is a little stretch but with just a little sanding of the end of the screw which screws through the bottom plate and it all went together just fine. But, I noticed that the top plate, where the ball joint from the previous post will get attached looked small. It was too small, by a lot, to take the ball join socket part. So, back to Fusion 360 where I made the spot for the end of the one screw a little bigger and deeper and put an appropriately sized mount on the top.
I reprinted and you saw the results above. I’m not calling this beautiful or the best design ever, but it works, and given I’m so rarely sober anymore, pretty amazing I got as much done as I have so far.
There was a little more work and drama behind the scenes but if you want drama there’s plenty of that on TV. Check out this post if you’re interested in Fusion 360 and want to learn more about what I learned about printing threaded fasteners as part of getting this working.
What’s next
I’m already working on printing out “arms” for the Webcam Positioner which will integrate with the ball joints. It takes a lot of time to write one of these posts with the reviewing and editing so it doesn’t suck too bad. I may just do one post covering the arms (they’re kind of boring anyway) and the mount for the Webcam which will get attached to the end of an arm. After that, I’m not sure.
[Update] OK. As I noted in my last Short Takes post, I kind of got busy with work and sucked into binge-watching some shows on Hulu. I had started this post and intended to post it weeks ago. I’m working on the final post for this project and a post for an Arduino-controlled light to accompany the 3D printer camera.
Also, please let me know in the comments if you would like to see time-lapse movies of prints? I have octoprint configured to take a picture with every new layer and make a time-lapse from it. The ones right now aren’t very interesting because the camera is not positioned well, but hopefully, that won’t be an issue soon.
I got some neodymium magnets a couple of days ago and I’m going to try to print a magnetic hook thing for my head-phones. I have a metal cabinet by my desk and I could really use a decent hook to put my headphones on when I’m not on a zoom call. I’m thinking of something where the USB charging cable is right there so I can hang and charge at the same time.
Final thoughts
Blogging is kind of hard work. It is harder than I thought it would be. There’s a lot that goes into this. Setting up and maintaining the blog site, tying it to social media accounts so people can get notified and notice the blog site. Posting to the social media sites. Responding to comments and posts. Scanning other related sites for interesting info (I need to get better at this) and including it here.
Then there’s the typing, the editing, and reviewing of posts. Taking and editing pictures. Occasionally, (so far not much since I’ve been focusing on my project) researching topics. I’m sure some of these things will get easier as I do them.
I also hope my writing gets better and more interesting with time as well. Please let me know in the comments what you think about anything, or if you have ideas for topics or what you’d like to see. I can’t improve and can’t improve the content if I don’t know what I’m doing wrong or what my reads want.
I have to admit I didn’t think of most of these things when I decided to do this. I may have decided not to, but I paid for the website for a year so there you go and I know it’s all necessary if I ever hope to not be typing for my own benefit.
I’ll leave you with this image … Berni Sanders inauguration figure pencil topper. Right. Am I right.
