Help with gears/ratio/reducer

Im sure we have someone here who is good at maths I am terrible and I am trying to work out how to turn my 10 turn pot 20tooth GT2 belt pulley into to a 1 turn Hall pot.

I obviously need to go small to big to small to big but I am just being lazy and asking first as it will be easy peezy for someone

Travel of the belt is 400mm so I need to turn that into 360degrees by not using a 100mm pulley lol

Once I know I can go print the relevant gears off and little housing for them.

if you make a i 10 gearbox you can use the same 20tooth pulley.
The gears you need pepends on the stages ,with 1 stage its 10 and 100 tooth or 12 and 120 tooth
with a 2 stage its two times i 5 two times 10 and 50 tooth
hope this helps

Sorry I should of been more specific. I am going to use my gt2 pulley and then attach spur gear to the same rod that the pulley is on. Then add another rod for gears and yes make hopefully a 2/3 stage gearbox with the hall pot as the last gear, and make it as small as I can, I only have about 80mm x 40mm x 40mm of room to play with

A lot depends on the gear module you gona use.(there a 2 types of gears imperial usa and module europe)I only know the module system .With mod.1 a 100 tooth gear is 100 mm of size on his hartline(where tooth totsh)a mod. 0.5 100 tooth is 50mm/a 1.5mod. 100 tooth is 150 mm
First you need to know how smal is the shaft to fit the first gear on, try to use mod. 0.5 and make it 2 stage, with a bigger module you need more stages with more backlash

I am going to use M6 thread for the shafts

You need a I 10 (I stand for reduction)This means the gear must have 10 times more tooth than the pinion fitted up pulley.
with more stages you have a lot of options to get to I 10.
To keep it simple with a 2 stage can go from first stage I 5 second stage I 2 (5x2=10)
or first stag I 3.33 second stage I 3,333,33x3,33=10)
the tooth from the first gear X wanted I give needed tooth for second gear
With a 10 tooth pinion an a I 3,33= 10x3,33=34 tooth gear needed
With 2 times a 10 tooth pinion and 2 times a 34 tooth gear you wil have a little bit less than 360 degrees of rotation on potty

A mod.1 10 tooth gears =10 mm on his hartline and11/12mm total
I have a fuw times used a m6 shaft for a 10 tooth mod.1 gear,with a lath but dont recomend it
A 34 tooth mod.1 gear got a 34 mm hartline and is 35/36 mm total

Thanks matey I have made these on thingiverse and I am printing them now to see if they work

http://www.thingiverse.com/thing:2084641

I wish I saw this post earlier ...

My suggest is using a worm gear box that can be at any ratio you need 5:1, 10:1, 40:1, 50:1, 60:1

You can salvage them easily from many sources : Angle grinder, car wiper and the windows motors, old VCR mechanisms, a LEGO gears ... endless .

I can print worm gears also that would be a good idea but I have no idea how to calculate the size etc

That's easy I guess ...
Look at this Floppy/CD-ROM mechanism ...


you need to get one of these high pitch motor shaft as it advances the mechanism by let's say 0.5cm per motor revolution ...

then design/print a corresponding gear that meshes with it that has a perimeter length of 10 times that shaft pitch ...
so when the shaft revolves 10 ... the gear will have a complete 1 revolution .

Unfortunately I have this confirmed idea but I don't have a 3D printer
https://www.xsimulator.net/communit...th-ac-motors-finished.8349/page-3#post-111253

Bearings finally came and I put my first little gearbox together, really not so little lol but it works and the reduction is exactly the same rotation for my 10turn pots I did not need to change any limits in Simtools. Maybe a fluke but hey ho.



I just need to make it more compact

@SilentChill
I feel you have gone the extremely long way to get what you want.
You want to convert 400mm linear travel to 10 turn rotary motion.
So 400 divide by 10 =40mm travel per turn.
40mm circumference=12.732mm diameter
So converting 400mm linear motion to 10 turn rotary motion = 10 turns of a 12.732 diameter pulley.
Thats the calculation but as you are using GT2 it is really easy to work out.
400mm GT2 belt with pitch of 2mm =200 teeth.
So 200 teeth divide 10 turns = 20 teeth per turn

As you are using gt2 belt with a pitch of 2mm a 20 tooth GT2 pulley would do nicely and be exact.

No he wants to go from a 10 turn to a 1 turn pot

Sorry @SilentChill
my bad

Hah no probs, it's big and crude, I really need something smaller. One good thing there is no slack at all with the herring tooth gears.

PS 404 error.

Doh not published them lol

http://www.thingiverse.com/thing:2086384
and
http://www.thingiverse.com/thing:2086386

Why bother with all these gears? Perhaps a simple string potentiometer would work more efficiently. Even with hall effect contactless sensor:
http://www.thingiverse.com/thing:1926226



Mike

An easy way to get rid of one of the gear sets is to replace the 20 tooth GT2 pulley with a 60 tooth one, that will make it 3:1 so you need only 1 more stage of 3:1
Or replace the 20t gt2 with 40t gt2, you then need 5:1 stage.

You will need to position the pulley so that the 2 left tangents line up, the rhs doesn't matter.