Parametric Involute Bevel and Spur Gears by GregFrost

Today I was trying to design something with one large and one small gear making use of Cbiffle’s awesome Spur Gear Fitter Script and Greg Frost’s Parametric Involute Bevel and Spur Gears script.  Unfortunately, whenever I tried to create a large and a small gear, I always ended up with the small gear having no teeth! ¹²

Cbiffle’s script is really useful if you don’t want to get too deep into the math of making gears, but do want gears with a certain gear ratio that will mesh well.  It basically takes care of all of the math you would normally need to get good fitting gears from Greg Frost’s script.

I asked Syvwlch for advice about my toothless gear problem.  He suggested there was a bug in the Spur Gears Script that would cause gear teeth to disappear in certain circumstances.  His way of getting around this problem was to use a non-integer for the number of teeth!  I tried 9.99 teeth (which failed) and then 10.001 which worked!

Parametric Involute Bevel and Spur Gears by GregFrost

This OpenSCAD script provides modules for both Spur and Bevel Gears. It has some major enhancements over my original gear script thingiverse.com/thing:3534. It uses some of the spur gear nomenclature code from TheOtherRob github.com/TheOtherRob/MCAD with my own code for generating the involute teeth. The bevel gear is also my own work. Thanks also to elmom for some enhancements to my original gear script thingiverse.com/thing:3547. Enhancements include the Bevel gear module, backlash settings, parameterised number of facets for the involute curve and whole of tooth generation to avoid some of the issues the original script had when mirroring a half tooth. The STLs provided are not intended for direct use, but instead show examples of what can be done with the parametric script. Parametric Involute Spur Gears take the following parameters:number_of_teethcircular_pitch or diametral_pitch: controls the size of the teeth (and hence the size of the gear).pressure_angle: controls the shape of the teeth.clearance: The gap between the root between teeth and the teeth point on a meshing gear.gear_thickness: the thickness of the gear plate.rim_thickness: the thickness of the gear at the rim (including the teeth).rim_width: radial distance from the root of the teeth to the inside of the rim.hub_thickness: the thickness of the section around the bore.hub_diameterbore_diameter: size of the hole in the middlecircles: the number of circular holes to cut in the gear plate.backlash: the space between this the back of this gears teeth and the front of its meshing gear\'s teeth when the gear is correctly spaced from it.twist: for making helical gears.involute_facets: the number of facets in one side of the involute tooth shape. If this is omitted it will be 1/4 of $fn. If $fn is not set, it will be 5. Parametric Involute Profile Bevel (Conical) Gears take the following parameters:number_of_teethcone_distance: The distance from the pitch apex to the outside pitch diameter.face_width: The length of the teeth.outside_circular_pitch: The circular pitch at the outside pitch diameter.pressure_angle: Defines the shape of the teeth.clearance: Gap between the tip of the teeth on one gear and the root of the teeth on another meshing gear.bore_diameter: The size of the hole in the middle.gear_thickness: The thickness of the gear for bevel_gear_back_cone finish (see below). backlash: Makes the tooth width smaller to make a gap between teeth of correctly spaced gears to allow for manufacturing tolerances.involute_facets: As for spur gears.finish: Specify either bevel_gear_flat(0) or bevel_gear_back_cone(1). If you don't specify this parameter you will get a flat gear for pitch angles less than 45 degrees and a back cone gear for pitch angles greater than 45 degrees. The example shows both with the small gear being the flat one. Update: v5.0 Implements backlash for bevel gears (This was not working in v4.0).

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Spur Gear Fitter Script by cbiffle

I've been working with Greg Frost's gear generator. Getting the gears to mesh requires some math, or trial and error. As a programmer, I don't like doing either one more than once. :-) This script lets you specify the axle spacing and gear ratio and get the circular_pitch parameter. It simplifies fitting gears together.

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http://store.makerbot.com/stepstruder-mk7-complete.html

1. And, thus, the importance of flossing! [↩]
2. I included the flossing reference because it was amusing.  But, really flossing isn’t relevant if you’ve got a MK6 or MK7 extruder. [↩]

Traced Snowflake by Landru

While there are no shortages of snowflakes on Thingiverse, this may just be my favorite.  Landru explains how they created this design:

“Traced a real snowflake (with magnification of course), which will no longer be unique.”

I don’t know whether it was Landru’s end goal to make this one snowflake no longer unique, but it certainly seems the only plausible explanation for going through the trouble of tracing an actual snowflake under magnification. ^1 2

Traced Snowflake by Landru

Traced a real snowflake (with magnification of course), which will no longer be unique. It prints really well, but my camera is temporarily dead so pics will have to wait.

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Traced Snowflake by Landru

1. Well, I guess Landru could have been interested in preserving the snowflake in digital form… but then there would be no need for mentioning that it is no longer unique. [↩]
2. I suppose it could also be a statement about how we all need to divorce ourselves from our belief that we are unique and our egos. [↩]

Here at MakerBot, we believe that children are our future. Imagine what your life would be like if you had owned a MakerBot as a kid!

The media is picking up on this idea too. Check out this piece in Forbes, and this one in the Wall Street Journal, covering MakerBot’s mission to get Thing-O-Matics into the hands of the next generation.

MakerBot is already in a number of schools around the U.S., including New York City public and private school teachers and NSF funded GK12 fellows from NYU-Poly University. Want to get MakerBotting on the curriculum at your or your child’s school? Email education@makerbot.com and check out our sample curriculum here.

Thingiverse user Curlrup has a plan: he’s starting a blog which will be dedicated to printing his favorite Thingiverse objects.  His goals?  Promote 3d printing in general, and help seed creative activity by bringing designs from the community into physical fruition.

The only catch?  He doesn’t have a MakerBot yet — but he’s got a Kickstarter project to help with that.  He plans to give away his quotidian output to the kind souls who help get it started. If you kick in enough, he’ll even print an object of your choice!

Welcome to the MakerBot Community and good luck with your project!

Thingitag Jr. by whosawhatsis

Please consider this a public service announcement on the issue of tags.  There are now more than 10,000 things shared on Thingiverse, which means it’s getting more difficult to find what you might be looking for among all the other things out there.  Fortunately, Thingiverse citizens have the ability, nay – duty!, to add tags to the things they see.

So, if you’re adding something to the universe of things, please be sure to add a few tags so that a week from now they’ll be easy to find even when your designs are no longer on the front page of the Newest Things.

And, if you’re cruising around Thingiverse and find something that would benefit from an additional tag or three, please help out everyone and add those tags!  One of the best parts about tagging someone else’s Thing is that when you do, Thingiverse instantly displays the number of things that share that tag, showing you all the other awesome related things you might otherwise miss out on!

Thingitag Jr. by whosawhatsis

I was showing off some of my designs at a recent Makerbot user group meeting, and I wished I had tags for them with QR codes and some other relevant data. This bookmarklet will generate such tags. This is a smaller version, with the QR code on one side and the human-readable information on the other. Note: I initially set the license to CC-BY for the example picture because the CC licenses look a little nicer on the tags, but I've changed the license to PD, so feel free to use it however you want. Update: Some errors were reported with the DOM walking, so I rewrote those portions to use Regex instead. This should improve compatibility.

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Parametric Tardis by Gossamer

If there’s something that’s even better than a regular TARDIS, it’s a parametric OpenSCAD TARDIS. ¹  In the true spirit of Thingiverse, the designer Gossamer, shared their designs and source code.  Doing so allowed other users to join in, offer suggestions, and Gossamer immediately updated the TARDIS code to incorporate these improvements.

Here are two OpenSCAD pro-tips:

• Best Programming Practices.  OpenSCAD for Windows tends to freak out when you don’t add a leading “0″ to a decimal.  By adding writing “0.5″ rather than “.5″ you can ensure compatibility across platforms.  Thanks Bluemetal!
• Too Many Elements.  Sometimes OpenSCAD will complain that there are too many elements.  You’ll see this happen a lot more when you’ve got some “for loops” or lots of nested functions. By adding “render()” before a group of code, you force OpenSCAD to render and cache that group of code.  Each successive render will be a lot quicker. Thanks Tbuser!

What other OpenSCAD tips do you have to share?

Parametric Tardis by Gossamer

None of the Tardises on here were quite what I was looking for, so i decided to make one myself. I tried to make it as parametric as possible, but you'll still find some things, such as the depth of the face impression, that are static. I'm working on an accompanying insert that will light up the light on top from the inside, I'll add that as a derivative as it develops. Let me know if you find any parameters that aren't scaling/re-sizing properly. EDIT: Per suggestions from Bluemetal and Tbuser I've added leading 0s to my decimal values and added render() to the face module, so it will now compile(F5) properly.

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1. And, goodness knows, I feel compelled to blog anything Doctor Who related. [↩]

MakerBots are the new rock stars! Rolling Stone paid a visit to our Brooklyn workshop for this profile that just ran on their Gear Up Tech blog. Check out the new video we created for those Rolling Stone readers who are new to the idea of MakerBotting. Bre created this How-To video covering the basics for any 3D-printer novice.

It’s not unusual for us to receive requests for DXF files for our MakerBot machines and Scott Hunter did just that – asking for the files that would enable his group of students the ability to replace the wooden components of his school’s Thing-O-Matic with various colors of acrylic. What caught my attention was that his students were 12 year old girls, from Scotland, with a penchant for designing the future of Formula 1 cars. Yep.

The students, involved in the F1 in Schools Technology Challenge, are using CAD/CAM(Computer Aided Manufacture) software to communicate their vision. The participants are encouraged to consider everything from physics, aerodynamics, design, and manufacture, to branding, graphics, sponsorship and more. It’s a comprehensive competition with wind and smoke tunnels, culminating with a race down a 20 meter track with the cars going as fast as 60 kmh (over 37 mph!).

The competition permits the use of 3D printers for the front and rear aerofoils of their miniature gas powered balsa wood F1 cars (manufactured on a CNC machine), and Scott’s team chose the Thing-O-Matic to help them get to the finish line. As you can see from the photo above, it’s looking great! With an international field of contestants (34 countries) aged 9-19 (for a total of 12 million(!) students), and fierce competition, the Challenge is more worth following…if you can keep up.

Hey MakerPeople! This friday, we are going to have a hyper-fun mega-event at Manhattan’s über-hip AC Gears store!  There will be refreshments as well as a DJ — that’s right, a professional Disc Jockey, who will be playing all the latest dance hits on an up-to-the-minute solid-state Hi-Fi!

AC Gears is on E. 8th St in Manhattan, and it’s a small place, so an RSVP is required on the official Facebook invite page.  See you there!

Well folks — it’s gotten to be that time of the year.  I hope you’ve stored away enough nuts to make it through the winter.

If you haven’t, perhaps you can print out an army of these squirrels by MBCook to help you gather enough to get you through.  I suspect ABS (or PLA) squirrels don’t eat very much…but then maybe they’re not quite as quick as real squirrels either.

Whatever the case, it’s clear that you need a whole lot of plastic squirrles for a crisp fall day like this.

Squirrel by MBCook

This is a 3D model of a squirrel that I found on Aim@Shape [1]. It was uploaded by MPII and is actually under the MPII Institute License, which you can view by clicking on the download link on the things page at Aim@shape. I flattened the base and cleaned up some artifacts on the tail that I'm guessing were the result of scanning. This is the most work I've ever done on a model (I used Netfabb and Blender to clean it), so I learned a lot, and he came out very cute. My print came before I caught an error in the model, which caused the bandana looking line. It slices correctly now. [1] shapes.aimatshape.net/view.php?id=105

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