We have an encounter!

Mashing up J. Allen Hynek’s famous UFO encounter taxonomy, with Dr. Bulinski’s shell assesment guidelines, we have Crab Encounters!

• Crab Encounter of the First Kind: Examination
• Crab Encounter of the Second Kind: Switching
• Crab Encounter of the Third Kind: Adoption

Last night an encounter of the first kind happened! Kourtney Karshellian examined a 70% sized ABS Prototype Shell 01 (Wednesday November 02, 2011 at 03:15:00 AM PDT) and here’s the video evidence:

Not to be outdone, Kourtney’s sister Khloe, spent even more time examining the shell later in the morning (Wednesday November 02, 2011 at 11:09:00 AM PDT):

So in one 8 hour period two encounters of the first kind happened! Prototype Shell 01 is being recognized as a shell!

Who can design a shell that will result in an encounter of the second kind? Upload your designs to Thingiverse, tag them with shellter and we’ll print them on a Thing-O-Matic and find out!

One more thing, install the video feed bookmarklets and watch the ShellterEast and ShellterWest crabitats live. Maybe you’ll be the first to see the next crab encounter!

This guest post is part of Project Shellter.

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).

This thing brought to you by

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.

This thing brought to you by

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.

This thing brought to you by

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!