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mgg942

1,048,576:1 Planetary gear set derived from "Tiny Planetary Gears Set" by aubenc

by mgg942 Dec 25, 2013
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can it work reverse direction means instead fast to slow make it other way slow to fast movement?

No, the amount of torque required to start any motion would rip this thing apart.

If you have a 2:1 reduction gear, and apply for example, 20 N/cm to the input shaft (the output of a standard NEMA 17 stepper), you'll get 40 N/cm out but at half the speed.

If you invert this example to a 1:2 ratio, you'll need to apply 40 N/cm to get 20 out. If you jump this up to 1:1,048,576, you'll need to apply 20,971,520 N/cm to get your 20 N/cm back out. To put that into more head-wrappable terms, that's 154,677 ft lbs of torque (or about 280 horsepower, which is about the power output of an average 4 door car) you'd need to apply to get the same output power as a NEMA 17 motor.

A $2000 air powered impact gun that a professional automotive mechanic might use will physically break at around 1,500-1,700 ft lbs.

Are the solid files available for this by chance? STEP preferred.

I have no access to the gear files you'd have to approach aubenc for those.

This was before I got in the habit of stating what material I used, and the supplier.
I can be certain that it was PLA because I did not have the capability of using ABS. However I can't tell you the supplier, though it may well have been Diamond Age.
PLA is pretty brittle. Some colours have the side effect of reducing brittleness to some extent so it may be worth your while trying a different colour.
If you can't solve with colour change, or perhaps a higher extrusion temperature, then I'd recommend Polymaker's PolyMax PLA which is significantly less brittle than regular PLA. - and prints very well!

What material was this printed with? I have been trying to print it with PLA but the small axes on the bottom ring keep snapping.

So... How many stages to make it slow enough that the heat death of the universe gets here before just one revolution of the output?

Depends on how fast you turn the input!

Comments deleted.

thing i love about this even more than the massive reduction, is the fact that it is just awesome to tell people "I have a 1.048 million:1 gearbox, but it is not hooked up to anything!" then see the reactions...

Me too - ihe magic million.
What's if for? Some people ask.
To amuse, amaze and astonish! Isn't that enough?

I'd like to see one with the output gear removed and a solid endplate in place. Theoretically, the drive would tear itself apart eventually. Realistically, it is a great conversation piece when someone is cranking away and it seems as thought the energy input is not doing anything, I seriously doubt that unless hooked up to a motor it would ever get turned enough to matter.

Wow! You do have destructive tendencies!
Engineers (and other technically minded bods) are impressed by a million to one gearbox - most everyone else fails to see the sheer magnificence of it.
I did try driving it with a cordless drill running at low speed, but I didn't continue for long as I was worried about overheating.

I've posted an extremely boring video showing the movement of the pointer by making a clip from 21 stills shot 100 turns of input apart: http://youtu.be/tc6ZZ3E_38Yhttp://youtu.be/tc6ZZ3E_38Y

I've thought of a less elegant method - but one more suited to my capabilities. I've designed and printed a 180mm radius pointer and a hub on which to mount it. stl files posted.
Then I mounted the gear set in a vice and photographed the end of the pointer against a reference, then turned the input crank 100 times and took another photo, and repeated this 20 times. A posted photo shows the crude set up and the distance the pointer moved after 2,000 turns. This is a pretty crude system, but taking the 2.6mm at face value the gear set ratio calculates to close to 900,000:1. Pretty close, I reckon.

To observe the output shaft turning you may want to try this:
attach a small mirror and shine a laser pointer on it.
The reflected spot on a distant wall shoud move visibly.

What a good idea. I'll see what I can do - thanks.