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What's on my bench: Pinwheel gears


 

Greetings from San Diego.
The automata that I am working on right now is for my Jim's Gym series.  These Jim's Gym automata are operating exercise machines, typically that lift marbles up so that they can roll down.
The one that I am creating now is called Auger Lift #1.  The biped pedals a sort of elliptical machine, which turns the auger, which raises the marbles.
I've not used pinwheel gears before, but I've recently gotten proficient enough with my 3D printer to design and print a couple of them.  The pins are stainless steel roll pins 1/8" X 1".  The piece holding the pins is 60mm in diameter.  You can see the auger and a 1" marble in the background.  Another reason that I am using the pinwheel gears is that the two shafts are at an odd angle to each other...not parallel and not at 90 degrees.
As I operate this set of pinwheel gears I am super impressed with how smooth and quiet they are.  I cannot feel any 'thumpiness' in the action.  Just smooth transfer of motion.  And it is this project that has made me realize (after just 1 month of ownership) that my 3D printer is not just a nice to have curiosity...it is an essential tool.  It is helping me do a better job.
Would love to see what's on your bench.
Cheers
-Jim Coffee-
PXL_20201115_013825680-1000.jpg


Lee
 

JIm,

How long do these wheels take to print? Do you think you will print all your drive trains now, or mix and match? I can imagine the wheel and holes is still quicker in timber with a pillar drill, but the printer really appeals to me for the accuracy and strength on the bearing housing.

Lee


Randy
 

Hi Jim,

You are making quick progress with 3D printing. When I started, I had a lot of bed adhesion issues and it took around 3 months to resolve them with bed leveling modifications and special first layer slicer settings. Prints are pretty reliable now. It is so nice to be able to try something out so easily and cheaply. It reminds me of the freedom given by transitioning from camera film to digital prints.

You may want to consider printed bevelled gears to address the odd angle issue. Even the auger gear may be printed using a worm gear. This resource on Thingiverse allows you to create STL files of all sorts of gear combinations.

-Randy

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Hi Lee...
  • It took 4 hours to print a pair of them.  I print at "high detail" settings.
  • I will mix and match.  I'm not married to the 3d printer.  In this case, I believe that the printer has done a better job than I could have done in wood.
  • I don't believe that I could have created two of these in the time that it took me to work up the design in FreeCAD.    It's true that it took 4 hours to print two, but I'm not sitting around waiting...I'm doing other things.  Had I created these in wood, the largest challenge for me would have been getting the holes 'exactly' 30 degrees apart.  And note how close to the edge I've been able to place the holes.  What I find when trying to do very precise drilling in wood is that even a small amount of hardwood or grain can cause the drill bit to drift a bit.
  • Another consideration is that now I have the software design created.  Obtaining two more of these is simply the push of a button (and a four-hour delay).
  • I've added an image (below) that shows the front and back.  These are not simply discs with holes.  I find them to be a bit more elegant than that.
Bottom line...I love working with wood (and brass and leather and etc.).  I appreciate the 3d printer doing some of the more mundane 'non-creative' components.  That said, as I become more proficient with FreeCAD I'll be able to be more creative with the software designs.
Cheers
-Jim-
PXL_20201114_231022188-1000.jpg


On Sun, 15 Nov 2020 at 08:34, Lee via groups.io <Helloleeturner=btinternet.com@groups.io> wrote:
JIm,

How long do these wheels take to print? Do you think you will print all your drive trains now, or mix and match? I can imagine the wheel and holes is still quicker in timber with a pillar drill, but the printer really appeals to me for the accuracy and strength on the bearing housing.

Lee


 

Hi Randy...
I've never seen another 3d printer in operation so have very limited knowledge.  I've had very few bad first layer adhesion issues.  The Prusa Mini does a bed leveling routine every time before printing.  And then as the 1st layer is being laid down I have the ability to fine-tune 'live' the bed height so that I can get the correct squish (nice fancy technical term).  
Thanks for the Thingiverse link...I had not seen that before and I'm sure I'll find it useful.
One of the reasons that I'm using a pinwheel gear is because it's large and kind of showy.  I like some of the drive components to be prominent...as points of interest.
Yes, it is nice to be able to try something out easily.
Cheers
-Jim Coffee-

On Sun, 15 Nov 2020 at 08:42, Randy <rglissmann@...> wrote:
Hi Jim,

You are making quick progress with 3D printing. When I started, I had a lot of bed adhesion issues and it took around 3 months to resolve them with bed leveling modifications and special first layer slicer settings. Prints are pretty reliable now. It is so nice to be able to try something out so easily and cheaply. It reminds me of the freedom given by transitioning from camera film to digital prints.

You may want to consider printed bevelled gears to address the odd angle issue. Even the auger gear may be printed using a worm gear. This resource on Thingiverse allows you to create STL files of all sorts of gear combinations.

-Randy

image.png