Working Micro Gear Heart Keychain

by CrazyJaw, published

Working Micro Gear Heart Keychain by CrazyJaw Jun 10, 2012

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Based on Emmett's ever popular gear heart: http://www.thingiverse.com/thing:12208

This version is about half the width of the original (50 mm), which means its 1/8 the volume and a much faster print (yay math!). i find it takes me ~2 hours to print one (and ~8 for the original)

Rather than just being a straight scaling, this version has been tweaked so taht it will still rotate. The main differences are the number of gear teeth (much fewer, and larger), gear ratio (it now takes 2 rotations to realign, unfortunately) and pins (made much beefier, and they are all one length).

Additionally, there is a hole through the tip so that it can serve as a keychain! Print them out by the dozen and give them to friends/family/cute girls on the bus!

== Edit 6/10/2012 ==
Added a zip of the source plus .stls for every individual component.

Added a "full plate" that prints all the gears + center. Left the pins out, since you usually want to print those with different settings. Fits on a replicator (not sure about others...)

== Edit 6/16/2012 ==
Added a chain connector to gear1 (the top). Updated the src rar (and fixed a compilation bug).

== Edit 6/19/2012 ==
Fixed the length of the pins. Shorted now, so gears should be less wobbly.


Print the two gear plates, the center, and the pins.

I've included the a zip of stls for each individual gear as well, along with the modified source openscad file.

I used a raft with .2 layer height, 10% infill and 50mm/s feed rate for the two plates. The center prints fine without a raft.

The pins are the key to getting the damn thing to actually rotate. Use a "multiply" profile to print the 8 pins necessary. I actually usually print 10 in a go, since usually one or two will have some flaw that makes it too loose to work correctly. The best settings I've found is to use a .3 mm layer height and 100% infill.

Then, just make sure you do a quick sand of the gears where they contact the center, and trim off any little protrusions that may be on the gear teeth (these can cause the gears to skip).

The largegearplate and fullplate have the keychain hole on the 8th (bottom) gear. You can separately print "keychaingear1" if you want the keychain connector up top

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not working with pin 95%, 90%, 85%, 80%. 85% or 80% is too small for feow part, but center. 95% or 90% is too big for heart pieces. this is not working at all. i print at least 30 pins.

Jun 18, 2015 - Modified Jun 18, 2015
DevWolf - in reply to scsonic

Use .3mm layer, slow down to as slow as 3mm/sec. print multiples at the same time and make sure Zhop is on. It needs to be really hot for some filaments. I used tglase and printed them at 245C. Do not reduce size. Keep them at 100%. if they are too big or too small at that point, its because you haven't properly calibrated for your filament diameter or its cheap filament. You will always have a couple that dont fit, so print like 12 at a time. I had to sand some of mine to get them to snap in. Everything is printed at 100% scale, it works fine. If it seems the center is too big, chances are its not the center, its your pieces that warped on the teeth tips, or you have the bed level too close for the first layer, so it squishes it and builds up pressure so the first few layers are way too wide, this happened to my first attempt. This is a very complex process man, make sure youre ready for this headache. I would reprint everything and sit there and watch it, repeat till perfect. If this was your first heart print, you cant expect it to work. You have to learn your own machine, theres too many variables. Basically if you arent prototyping first, you cant complain about it not working, of course it doesnt. If people could press print on anything out there and have it print perfectly, they would be mainstream. But thats not for another 5-10 years. Right now WE are the developers in the FDM field.

A sido un perfecto regalo de San Valentin para mi mujer, muchas gracias por compartir tu trabajo.

Having trouble getting Slic3r to slice this correctly (full plate version) anyone else having issues with it? as far as I know I'm on the most up-to-date version

Same problem here. Turn settings checkboxes off and set infill to rectalinnear and at 0%, set surface to rectalinnear too, then save and restart it. Then import and it should work. But every time u change a setting, save them incase you run into whatever caused crashes. Still though, look at the layers for the small gears, it'll have a break between the teeth at the base. It won't print properly. Try CURA or Skeinforge/makerware or MPrint from MBot.

For PLA shrink the diameter of the pins to 85% to get it to work perfectly.

This comment has been deleted.

Congrats! I thought you model was one of the best choices for a 3D Printed Christmas gift! I made a link from here: http://3dprintingninja.blogspot.com/2014/12/top-20-free-3d-printed-christmas-gifts.html

im having trouble assembling this... its my first gear thing :)
what is the correct placement and direction of all the parts?

I was so curious to try my brand new Replicator 2 that I've missed the comments to the thing. This resulted in waste of plastic for 10 pins originally included in this model :D It is impossible to fit them. The print was made using PLA. Will try these little fellas tonight: http://www.thingiverse.com/thing:40600http://www.thingiverse.com/thi...

Updated Pins for Micro Gear Heart

The pins are supposed to be hard, you really have to force them but once they snap into place, it works perfectly. Too small and the gears wobble.

Your awesome gift idea was featured in the latest Fused News episode about 3D printable valentine presents. You can check it out here - http://www.youtube.com/watch?v=3s8M1dHwiNs&feature=youtu.behttp://www.youtube.com/watch?v...

Whouah, great to do it in 2 hours, but it seems really IMPOSSIBLE to fit the pins into pieces, it's to large, i print in PLA with replicator 2 at 0.2mm ... did you have a solution for the pin ?

Ur supposed to do .3mm and try speed at 3MM/s, I know it's slow but it will work.

yeah the pins were designed around ABS, which has a tendancy to shrink (pla doesn't). LittleDangerous has a derivative that takes care of that though: http://www.thingiverse.com/thing:40600http://www.thingiverse.com/thi...

Updated Pins for Micro Gear Heart

The ones it comes with work just fine when u know what youre doing.

So I finally got this to work well with the following changes:


This is, again, with ABS at .27mm layers on a thingomatic running at 60mm/s with sailfish. Sliced with skeinforge with stretch turned off and with 0 extra skins and 10% infill. The prints were raftless on a steel heated build platform at 100c covered with 'ABS juice'

This is in case anyone else has the same issues I did - i.e. the default pins being too long (by about .6 mm) and far too thick and with too large a lip to snap into the holes and there being far too much friction for the parts to turn easily.

Thanks for the design ="thingiverse-18b67afe27829441b0845c36bfbc30d1:disqus" href="http://disqus.com/thingiverse-18b67afe27829441b0845c36bfbc30d1/CrazyJaw ! :)

So I printed these at .27 mm on a thingomatic (mk7 extruder + sailfish) with stretch turned on to make sure the holes weren't too small and I still couldn't get these to fit without drilling out the holes.. Any idea what I am doing wrong?

you using pla? you may want to try the pla pins derivative.

Also i always use needle nose pliers to get the pins in, and i pinch the tips before forcing them in.

ABS. Printed raftless on a steel heated build platform. The crazy thing was that I tried the PLA pins as well and they wouldn't fit without enlarging the holes either. This happened with the side holes on the center as well - so it isn't an artifact of printing against the base.

Thanks for the great model! Printed in PLA; had to dremel down pin heads to fit; I should have used the PLA-adjusted pins. 5hrs on Replicator 2 PLA, High, 24grams.

Can anyone give me tips for using the source? I'm not much of an OpenSCAD user, but it just won't work for me. I get the following messages:
WARNING: Can't open 'use' file 'C:\Users\Zak\Desktop\openscad/involute_gears.scad'.
WARNING: Can't find 'include' file 'pins.scad'.
WARNING: Can't open 'include' file 'pins.scad'.
Module cache size: 0 modules
Compiling design (CSG Tree generation)...
DEPRECATED: The import_stl() module will be removed in future releases. Use import() instead.
WARNING: Ignoring unknown module 'bevel_gear'.
WARNING: Ignoring unknown module 'pinhole'.
Rendering Polygon Mesh using CGAL...

yeah i remember having problems getting the include statements to work the way i wanted. I dont remember the issue exactly but in the end i just had to spell out an absolute path rather than a relative path for the includes.

Has this been successfully printed in PLA?  I'm at a loss as to how the pins are to fit into the holes, as they're significantly larger thant the holes and PLA is very stiff and unyielding. Mine just won't go together, and the prints are fairly close to the stl dimensions.

Thanks in advance for any advice.

I'm having the same problem.  Did you ever get this to work in PLA?

I had the same issue, the pins would not fit at all, so I modified the pins so they fit better: [url]/thing:40600[url]

Updated Pins for Micro Gear Heart

I have not got it working, but I was able to get most of the gears in place, by soaking the PLA part in hot water to soften them up.

Its definitely calibrated to ABS, with its shrinking issues... I personally have never printed it with pla, though it looks like one or two of the "i've made ones" have been in pla... you may just want to try some very slight scaling, like 99%. Too much and you'll probably have other issues. This may require some tweaks to the pin code to do right.

FWIW, I've had good success printing the large and small plates raftless at 0.15mm and 0.20mm but with acceleration. The gentleness of acceleration may help prevent dislodging the pieces. (Was ABS with a HBP on a ToM+Mk7 printing at 120 mm/s.)

Good news! The new pins work great and make the heart much more solid feeling. Thanks for fixing that for me! =-X

I've printed 3 of these and the only improvement I could suggest is to make the pins a tiny bit shorter. I think that might help with the looseness of the gears. I'm talking about shortening the shaft of the pin by a tiny amount so the gears would be tighter to the center.

Good call. I definitely screwed up the math on the pins lengths (and just ended up subtracting some random magical value to compensate). Made them about a millimeter shorted and it seems much tighter now.

I've replaced the pins in all my hearts and they are much tighter. Thanks for fixing the pins.

Great print. But how the hell do you put it together???? Is there a guide somewhere showing what part attaches to what face ?



Haha, good question. It's similar to the large heart instructions. Basically, the small gears go on the small faces of the center, and the big gears to the big faces.

Beyond that, it comes down to "assemble it so it looks like heart". This should mostly be straight forward (as long as you fall the rule above), however there are two pairs of gears that look the same, but are actually mirrored (so they go on specific sides).

Best advice is to use the picture as
a template, and if you get it fully assembled but it doesn't quite look right, try swapping the mirrored gear pairs.

Hi CrazyJaw, thanks for the tips, I managed to get it together and wow everyone I showed !

I grow oranges for a living and would love to see perhaps oranges and apples with this gear design. Just a thought 8-)

Thanks again.

Oops, that was supposed to be "WOWED" everyone I showed....

Think I could get a version of the bottom gear without the keyhole in it so I can modify the design?

the .rar has all the individual gear stls (some of which might be an older version, in which the new pins wont fit), and the actual openscad source for everything, so you can modify and export however you see fit.

Open SCAD doesn't work for me. This is news but I've tried every computer I have available but when I press F6 the thing dies. All I need is it heartgears.scad run with isAttachment=false and I can do the rest.

AWESOME job!!! I got all caught up in college classes, so wasn't able to keep working on this, but you've done an amazing job! I can't wait to print a bunch of these once i'm back up to full printing speed!!

Could you change the design of the topmost piece (heartger1 in the original screwless gears) so that it has a loop to hang the heart from? This design http://www.thingiverse.com/thing:16893http://www.thingiverse.com/thi... has the hook, but it isn't a functioning design. It looks and functions awesome as is, but it just looks cooler when the heart is upright. Kudos on the design as well :)

Keychain Screwless Heart Gears
by Zh4x0r

Thanks! Ill see if i can get some time to do it this weekend (though i prefer the hole at the bottom, makes rotating it a little easier and more intuitive than at the top, since top and bottom rotate in the same direction)

First round came out pretty good. Nice work! I tweaked the layout a little of each of the STLs so that it can be dual-struded to produce two at once. For the pins, I did two sets of pins, then dual-struded them for a complete set in one print. Let me know if you want the modified STLs - I can post a derivative.

Yeah sounds cool (I've yet to use the actual dualstrusion). You should post a derivative.

Ditto on posting the dualstrusion plates. And nice job CrazyJaw, I can't wait to print a few of these. Get any dates from cute bus girls yet?

OH man, this is great !!! Good work! I've built the heart gear at least a hundred times now, from 6.5cm to 20cm across, but I've never got it to work this small. awesome stuff, I can't wait to print :)

Yay math indeed! thanks for the adjustments!

Neat! I'm manning a booth doing demos at a convention in a few weeks, and this would be perfect giveaways!

Do you mind sharing the OpenSCAD source?

Oops, forgot to include that. I'll be in the rar, under "src".