I revisited this DIY Folding Table Hinge build.
Вставка
- Опубліковано 6 лип 2024
- A walk through the design and build of Rev 2 (and Rev 2b) of the 3d printed folding table hinge from a while back. I compare the design to version 1, and explain my rationale for some of the design decisions. Then a quick description of the build process and a look at how it came out.
Full details on the build can be found here: jfs-agri.com/index.php/bubsbu...
Model Files
Thangs:
thangs.com/mythangs/file/1097843
Printables:
www.printables.com/model/9364...
Thingiverse:
www.thingiverse.com/thing:668...
Other 2020 Extrusion Parts
jfs-agri.com/index.php/bubsbu... - Наука та технологія
Corrections and helpful tidbits from the comments:
- In the "COTS" part of the video, I show a 3mmx15mm dowel pin, but that should be a 4mm x 16mm dowel. Doubt anyone was pausing there to place a dowel pin order, but figured I'd correct it just in case :)
- It was pointed out (thanks @mikemorrell7921) that Loctite can have negative interactions with some plastics. Although I haven't see any issues with these thus far, it's something I hadn't considered. So word of caution and maybe check yours on a piece of plastic scrap prior to following my lead on that one!
- Switching out the machine screws (that run through the bearings) for some shoulder bolts would reduce/eliminate the potential for damage to the inner diameters of the bearings. With a little bit of revision to the bearing design, they could actually be used directly as the radial bearings directly against the Base. Thanks @limeyrock for the shoulder bolt shout out!
Even though it's not a perfect project, I really enjoy the engineering perspective and the explanations of what went wrong and how you fixed it. Thank you for that! and keep it up.
Thanks! Really great to hear my decision to sketch load paths in a video wasn't aimed only at myself! :) Much appreciated
Thanks for the design details. This effort was certainly not trivial and sharing the design progression helps all us become more time efficient designers. First time visiting and this episode alone has earned a subscription from me. Headed to your video library now to see what else you’ve been up to. 👍👍😎👍👍
Thank you for the kind words! Glad to hear it was up your alley, and hopefully at least one or two of my previous builds didn't disappoint :)
I personally would add some way to connect 1/32" wire rope between the extrusion and some spot closer to the center of the table to stop the legs from bending outwards, but those can be a pain to tension and keep out of the way.
I hadn't thought of using some sort of cable stay supports to stiffen it up, I like it! True, the tensioning could be tricky, but not impossible. I'll have to ponder on that one a bit, thanks for the suggestion!
Shoulder bolts or at least just normal plain shank bolts of the right length would be better than machine screws for tolerance and longevity.
Very true and very good point! I actually considered switching to shoulder bolts as an alternative to the bearing revision I went with....but then I realized I didn't have any on hand, and I'm impatient :) But definitely agree they are a much better choice for this application. Thanks!
I had it laying around and was table like
😅
😁
The Algorithm brought me here. Nice.
Since you spoke about curiosity, what are those hole-thingys attached to your "table top"? Are they purely for aerodynamic purposes or just holes for where you put your lollipops when you need two hands?
@liveroundsgaming2359 All hail the algorithm.
Close! But it was actually for jerky, that way I could just bend over while working and grab a bite. But I got on a Slim Jim kick, and they just kept falling through the holes...hence it found its way to the scrap pile. Really they are just a 'standardized' set of mount points for tools, containers, etc. Kind of like a worse, and less versatile version of Gridfinity.
Pinky out for performance
😂
@justinbanks2380 it’s all about maintaining proper form 😁
Nicely done. The two bearing surfaces and lock with pins was a nice touch.
Any benefit to printing two of the hinges at a different orientation to change the layer path, stiffen them in a different direction?
Do you think a generative design may provide a stiffer solution quickly?
Have you noticed any problems with loctite interacting with the plastic? I found that some plastics weaken when loctite is around. Dont know if its just the solvent.
@mikemorrell7921 Thanks! Hmm, I hadn't thought about that option, it could indeed be interesting to play around with print orientations a bit (and maybe also fill %s) to see if there are any noticeable gains to be had.
I hadn't even considered tryin out generative design on this one! I'd guess one big improvement that would come from that would be in the side-to-side stiffness (assuming I remembered to apply that load case). Although I have never tried to set up a generative design solve that needs to have one of the components in two orientations, so reckon I'd have to figure that out. But if I do indeed take yet another dive into this folding table hinge down the line, I think I may very well try going that route!
I haven't! That's EXTREMELY good to know! I haven't used it on any previous plastic builds (that come to mind), and that didn't even cross my mind as a concern. I'll add that word of caution in a pinned comment. Thanks for the heads up!
What software are you using to show/view the cutaway views and schematics like views?
I'm currently trying to learn fusion, but am open to learning others too
@justinbanks2380 I used Fusion for all of the modeling/cross-sectioning, and I just used screenshots pasted into Adobe Illustrator for adding the labels and load paths and such. And to record any of it that’s not static, I just use OBS Studio to screen record.
Your bearing axle design isn't very good. When you tighten the bolt you are also tightening the bearing, that's not good because it means that you cannot get the bolts tight enough without binding the mechanism.
I suggest you make the frame hole bigger and extrude the bearing disks to meet in the middle so that the bolt tightens the bearing disks against each others and against the aluminum extrusion. Also, add washers under the bolt heads. This way you can tighten the bolts tight creating the proper friction joint while still having a functional hinge.