Keyed Screwless Heart Gear Keychain Pendant

by latigerlilly, published

Keyed Screwless Heart Gear Keychain Pendant by latigerlilly Oct 8, 2012

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Keychain loop's position changed to be on top of the heart so that you could use it as a pendant on a necklace or as a car's rear view mirror ornament!

Update 10/17/12: I printed this out at 20% fill like everyone else but it broke. So, to increase durability, I printed it out at 50% fill. However, at 50% fill, the plastic heart is hard enough so that it won't deform anymore to accomodate the large diameter pins. Therefore, I redesigned the pins to be smaller in diameter so that it could be easily assembled.

Update Nov 1, 2012; New skinnier pins designed and the heart gears's stl file was recompiled from source and reposted, "keypins6, platenokey4b."

Update Nov 24, 2012; updated to new pins and key. I found out why some people get perfect fit while others mysteriously have pins that don't fit or was getting perfect fit and then suddenly gets pins that don't fit. Small features such as these pins are much wider than as seen on CAD software because the plastic's first layer is squished against the HBP, causing the first layers to be wider than they are supposed to be. Furthermore, the holes on the gear pieces are smaller than they're supposed to be for the same reason. Also, the holes on the central hub are not printed on the HBP so they are more size accurate. Therefore, there is very little print size variability tolerance so if your machine is slightly calibrated differently, the filament is slightly different in diameter due to different humidity levels, etc, then the affect on the pin size, though small, may cause it not to fit anymore. In other words, the pins are almost too big for the gears while almost too small for the central hub. I improved the pin design by making one end wider for the central hub while the other end is narrower for the gear pieces. I also shaved a little bit of width off the pin heads and the central key. I also included slightly smaller and slightly bigger versions of the pins and key, just in case. Perfectly sized and shaped pins and key file is keypins12.stl. Bigger perfectly shaped pins and key is keypinsbg.stl while its little sister is keypinssm.stl . Problem solved. Enjoy!

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I'll have to let you know the next time I print it out.  Thanks for doing the research to figure this out.

 All challenges fixed. Enjoy :o)

I've found that printing the pins on my Thing-O-Matic using 1 shell with 5% infill makes the pins usable.  Before I upgraded to Skeinforge 50 I used to print them with 0 shells and 100% infill and they worked.  However, since upgrading if I print with them with 0 shells and 100% infill they are too fat or tight to fit in the holes.

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Latest and best version are files PlateNoKey4b.stl and keypins12.stl.

Key printed at Makerbot Replicator default settings except 99% fill, no raft and 0.2 mm layer height in ABS.

Everything else printed at Makerbot Replicator default settings except 40% fill, no raft and 0.2 mm layer height.

Assembly instructions;
1. There are 7 pins. Each pin has a wide end and a narrow end.
2. With needle nose pliers, insert narrow pin ends into the gears.
3. Do not insert wide pins into central hub first as narrower pin ends are more susceptible to damage from needle nose pliers than the wider pin end. If the pin end is damaged, then the gears will pop out during use.
4. Using your palms and a lot of sweat, shove gears into the central hub.
5. key fits into the six sided hole on the 8 sided polygon center.

Check out the following video in slow motion to see where each piece goes in relation to the other pieces. youtu.be/SRU2ZG2oULU



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DJC on Oct 29, 2012 said:

I get these errors when generating the PlateNoKey4.stl file... any comments or ideas why?

[10:53:43] Warning, the triangle mesh slice intersects itself in getLoopsFromCorrectMesh in triangle_mesh.[10:53:43] Something will still be printed, but there is no guarantee that it will be the correct shape.[10:53:43] Once the gcode is saved, you should check over the layer with a z of:[10:53:43] 4.3

latigerlilly on Oct 30, 2012 said:

 Funny, I just printed out some and it did not give me these error messages. Anyways, I'm having trouble with the width of the pins that attach the pieces of the heart gears to the center. The original pins and key were too tight, so I made them narrower. Then, they were too loose. The funny thing is, others have printed these things fine with no modification of the width of the pins nor key. So, I'm now thinking, maybe I should print them out with zero shells and use 1.82 mm default filament width instead of measuring the filament with calipers and entering the measure filament width into replicatorg. I'll let you know what I find out....

MacGyver on Oct 11, 2012 said:

The whole point of the key is turn the center hub of the heart.  How does this make it better?  You may or may not have noticed that the center hub on the original has one hole that fits the key perfectly.  I've made about a dozen of them so far. 

I always print the key separately so I can print it with more infill so it doesn't bend when I turn the gears.

latigerlilly on Oct 12, 2012 said:

 Different strokes for different folks. Some like the key one way while others like the key the other way.

Also, I'm gonna move the loop higher so that it can be used as a pendant or car's rear view mirror decoration. Refer to the following thread for the request to make such a loop: http://www.thingiverse.com/thi... 

Also, refer to this thread for general confusion on how to put it together. http://www.thingiverse.com/thi...  That's why I posted a link to the video.