All gear ratios

[jxu]

Anyone have a list of all possible gear ratios? https://lego.jtooker.com/gear_ratios/ and http://gears.sariel.pl/ are good starting points but don't list out all ratios. The first site doesn't have 28 tooth gear (new gear or old differential) for factors of 7 nor worm gears. 

It's also clear that not all gears mesh together nicely, ex. the bevel and normal gears. I don't know what the old 14 tooth bevel gear or old differential casing meshes with because I've never used it. My assumption is that there are two classes of gears: bevel gears and non-bevel gears, and they should only mesh with each other. If that's correct, I can write a simple program that just prints out all ratios (it won't give the spacing in terms of liftarms which has some margin of error)

AFAIK the only ratios possible without using the differential have prime factors 2, 3, 5, or 7 (the first 4 primes). With the differential, effectively any gearing ratio is possible (though it may require several differentials in a row)

Edited September 6, 2020 by jxu

[Bluehose]

If you look about ratio with differential on this website, you will find a methode to make ratio different than regular ratio.

[howitzer]

3 minutes ago, jxu said:

Anyone have a list of all possible gear ratios? https://lego.jtooker.com/gear_ratios/ and http://gears.sariel.pl/ are good starting points but don't list out all ratios. The first site doesn't have 28 tooth gear (new gear or old differential) for factors of 7 nor worm gears. 

It's also clear that not all gears mesh together nicely, ex. the bevel and normal gears. I don't know what the old 14 tooth bevel gear or old differential casing meshes with because I've never used it. My assumption is that there are two classes of gears: bevel gears and non-bevel gears, and they should only mesh with each other. If that's correct, I can write a simple program that just prints out all ratios (it won't give the spacing in terms of liftarms which has some margin of error)

 

The old 14T bevel gear meshes with itself and the oldest of differentials and the old 24T crown gear. The 14T gear is very weak though, so unless you're reconstructing an old set there's very little reason to use it as it can't transmit much of torque but will break instead.

I think all the other Technic gears mesh together, double bevel gears can be used like spur gears so they also mesh with spur and rack gears with no problem. The very oldest of gears (pre-Technic) like Samsonite and Expert Builder gears don't mesh with Technic gears, and obviously neither do Duplo gears or the so-called splat gears (35446 etc.) but beyond those all gears should work together.

[jxu]

10 minutes ago, howitzer said:

The old 14T bevel gear meshes with itself and the oldest of differentials and the old 24T crown gear. The 14T gear is very weak though, so unless you're reconstructing an old set there's very little reason to use it as it can't transmit much of torque but will break instead.

I think all the other Technic gears mesh together, double bevel gears can be used like spur gears so they also mesh with spur and rack gears with no problem. The very oldest of gears (pre-Technic) like Samsonite and Expert Builder gears don't mesh with Technic gears, and obviously neither do Duplo gears or the so-called splat gears (35446 etc.) but beyond those all gears should work together.

So you're telling me the thin 12 bevel gears can be used with regular 24 tooth gears? It doesn't look like it would work, but I have never tried it.

[howitzer]

3 minutes ago, jxu said:

So you're telling me the thin 12 bevel gears can be used with regular 24 tooth gears? It doesn't look like it would work, but I have never tried it.

They are single-sided bevel gears so no, they don't work, and the same goes for 20T single-sided bevel gears. But you can use double bevel gears with 24T spur gears. The non-bevel spur gears naturally won't work in other positions than parallel and single-bevel gears work only in perpendicular position so they are incompatible. If you for some reason need a gear ratio of 1:2 in perpendicular position, you could use 12T double bevel along with 24T crown gear.

[jxu]

7 minutes ago, howitzer said:

They are single-sided bevel gears so no, they don't work, and the same goes for 20T single-sided bevel gears. But you can use double bevel gears with 24T spur gears. The non-bevel spur gears naturally won't work in other positions than parallel and single-bevel gears work only in perpendicular position so they are incompatible. If you for some reason need a gear ratio of 1:2 in perpendicular position, you could use 12T double bevel along with 24T crown gear.

Ok so there are three categories: double bevel, single bevel, and spur?  That would seemingly take care of all modern gears, except for maybe the 24 tooth crown gear which should go in the spur category.

There's also the inside radius of gears which probably fits into one of the above categories.

[howitzer]

53 minutes ago, jxu said:

Ok so there are three categories: double bevel, single bevel, and spur?  That would seemingly take care of all modern gears, except for maybe the 24 tooth crown gear which should go in the spur category.

There's also the inside radius of gears which probably fits into one of the above categories.

Maybe you should take a look at this: http://technicopedia.com/fundamentals.html. Somewhat out of date and incomplete, but still a great introduction to basics of Technic.

[Sariel]

Here: https://play.google.com/store/apps/details?id=pl.sariel.brickgearratiocalculator&hl=en
There's an option to define your own custom gears with any number of teeth (annular gears too) so that should give you any ratio you want.

[Oliver 79]

6 hours ago, Sariel said:

Here.....

Oh man! That is so useful. How have I not found this before? 

Thanks for your time and effort in building this tool! 

[Horologist]

10 hours ago, jxu said:

Ok so there are three categories: double bevel, single bevel, and spur?  That would seemingly take care of all modern gears, except for maybe the 24 tooth crown gear which should go in the spur category.

There's also the inside radius of gears which probably fits into one of the above categories.

All spur and double-bevel gears have the same tooth profile and can be meshed with each other. The only difference between the two (aside from the double-bevel gears' ability to mesh with each other at right angles) is in the number of teeth. The spur gears all have numbers of teeth that are multiples of 8 (8 tooth, 16 tooth, 24 tooth, etc.) and the double bevel gears have numbers of teeth that are multiples of 8 plus 4 (12 tooth, 20 tooth, 28 tooth, etc.). Together, they have all of the multiples of 4 from 8 to 40 except for 32. There are two worm gears, 32905 and 27938, which both have one tooth. However, the 32905 has a diameter of 1 (the same as an 8 tooth gear) while the 27938 has a diameter of 1.5 (the same as the 12 tooth gear). Because of this, 32905 works best with spur gears and 27938 works best with double bevel gears. 

[jxu]

9 hours ago, Sariel said:

Here: https://play.google.com/store/apps/details?id=pl.sariel.brickgearratiocalculator&hl=en
There's an option to define your own custom gears with any number of teeth (annular gears too) so that should give you any ratio you want.

Surely there's online version for these tools? I feel bad for all the iPhone users out there

1 hour ago, Horologist said:

All spur and double-bevel gears have the same tooth profile and can be meshed with each other. The only difference between the two (aside from the double-bevel gears' ability to mesh with each other at right angles) is in the number of teeth. The spur gears all have numbers of teeth that are multiples of 8 (8 tooth, 16 tooth, 24 tooth, etc.) and the double bevel gears have numbers of teeth that are multiples of 8 plus 4 (12 tooth, 20 tooth, 28 tooth, etc.). Together, they have all of the multiples of 4 from 8 to 40 except for 32. There are two worm gears, 32905 and 27938, which both have one tooth. However, the 32905 has a diameter of 1 (the same as an 8 tooth gear) while the 27938 has a diameter of 1.5 (the same as the 12 tooth gear). Because of this, 32905 works best with spur gears and 27938 works best with double bevel gears. 

Thank you for this helpful information. I and many others dream of the fabled 32 tooth gear. Maybe I will 3D print some and sell them on BrickLink - do they allow custom stuff like this? 

[TechnicRCRacer]

57 minutes ago, jxu said:

Maybe I will 3D print some and sell them on BrickLink - do they allow custom stuff like this? 

I believe since LEGO bought out BrickLink, they are starting to crack down on custom parts and they may not be allowed to be put up for sale.

[jxu]

2 minutes ago, TechnicRCRacer said:

I believe since LEGO bought out BrickLink, they are starting to crack down on custom parts and they may not be allowed to be put up for sale.

I thought that was only for guns and brickarms. There's evidently custom parts listed here https://www.bricklink.com/search.asp?itemType=P&catID=136&itemStatus=U but one is a misclassified panel with sticker and the other looks like part of 60c01. So we'll see.

[2GodBDGlory]

13 hours ago, howitzer said:

The old 14T bevel gear meshes with itself and the oldest of differentials and the old 24T crown gear. The 14T gear is very weak though, so unless you're reconstructing an old set there's very little reason to use it as it can't transmit much of torque but will break instead.

I think all the other Technic gears mesh together, double bevel gears can be used like spur gears so they also mesh with spur and rack gears with no problem. The very oldest of gears (pre-Technic) like Samsonite and Expert Builder gears don't mesh with Technic gears, and obviously neither do Duplo gears or the so-called splat gears (35446 etc.) but beyond those all gears should work together.

The old 14T does have a few more applications than that. I have used doubled ones against a 20T double-bevel gear (It can be (rarely) useful in gearboxes where you need to have a sequence of gears that goes 12-20-14-20, where the 12 and 14 axles need different ratios), and because they are doubled, I would imagine that they are tolerably strong. I imagine they could also work with 36T double-bevel gears easily, and probably other gears with unusual spacing.

1 hour ago, jxu said:

Surely there's online version for these tools? I feel bad for all the iPhone users out there

Thank you for this helpful information. I and many others dream of the fabled 32 tooth gear. Maybe I will 3D print some and sell them on BrickLink - do they allow custom stuff like this? 

Ah, the 32 tooth gear. Many are the times when I recline in a leather-backed chair (read: free desk chair that was going to the dump), holding a half-finished gearbox in my hand. Success is near, but yet impossibly far. A single 32-tooth gear, I know, could solve all my problems--worse, it should solve all my problems, but even after a period of forty-four years, this seemingly elementary gear is yet consigned to the the imaginations of Technic builders (and 3D printers). Shaking my head in disgust, I settle down to restart the gearbox, which will now inevitably be far larger and less efficient than it could have been, if only, if only...

[jxu]

48 minutes ago, 2GodBDGlory said:

Ah, the 32 tooth gear. Many are the times when I recline in a leather-backed chair (read: free desk chair that was going to the dump), holding a half-finished gearbox in my hand. Success is near, but yet impossibly far. A single 32-tooth gear, I know, could solve all my problems--worse, it should solve all my problems, but even after a period of forty-four years, this seemingly elementary gear is yet consigned to the the imaginations of Technic builders (and 3D printers). Shaking my head in disgust, I settle down to restart the gearbox, which will now inevitably be far larger and less efficient than it could have been, if only, if only...

It will be here Soon™. At least when I go back to university next semester and have access to a 3D printer. The original Shapeways product by Taran isn't sold anymore, but he has released the models into the public domain at http://taranvh.com/wp-content/uploads/sites/4/lego/3d_printing_files/. 

[howitzer]

7 hours ago, jxu said:

I thought that was only for guns and brickarms. There's evidently custom parts listed here https://www.bricklink.com/search.asp?itemType=P&catID=136&itemStatus=U but one is a misclassified panel with sticker and the other looks like part of 60c01. So we'll see.

I think it's all third party parts, but of course some haven't been found yet. In addition to guns and such, at least one shop selling chrome-plated bricks and one other selling generic hose for pneumatics have had to move their non-genuine parts business elsewhere.

[Sariel]

10 hours ago, jxu said:

Surely there's online version for these tools? I feel bad for all the iPhone users out there

Surely: http://tools.sariel.pl/

[jxu]

3 hours ago, howitzer said:

I think it's all third party parts, but of course some haven't been found yet. In addition to guns and such, at least one shop selling chrome-plated bricks and one other selling generic hose for pneumatics have had to move their non-genuine parts business elsewhere.

Yeah, I checked the items listing policy and custom pieces aren't allowed. I guess if I do end up printing pieces, they will be sold through eBay. (The BSTF subforum seems pretty inactive.)

@2GodBDGlory do you think there is sufficient interest in 32 tooth gear to sell them? I know I would not want to use custom parts unless I had a very good reason to.

Edited September 7, 2020 by jxu

[2GodBDGlory]

9 hours ago, jxu said:

Yeah, I checked the items listing policy and custom pieces aren't allowed. I guess if I do end up printing pieces, they will be sold through eBay. (The BSTF subforum seems pretty inactive.)

@2GodBDGlory do you think there is sufficient interest in 32 tooth gear to sell them? I know I would not want to use custom parts unless I had a very good reason to.

I couldn't say. I probably would be with you on sticking to genuine parts--that way, no one can criticize your work by saying "Well, anybody can build stuff like that if they use custom parts!"

And then, even if enough people decide that they are willing to use them, 3D printed ones would inevitably be significantly more expensive.

[jxu]

31 minutes ago, 2GodBDGlory said:

And then, even if enough people decide that they are willing to use them, 3D printed ones would inevitably be significantly more expensive. 

More expensive, but not prohibitively so. IIRC the original Shapeways cost was about $6, I could likely do it cheaper, and it could be much cheaper in bulk. That's comparable to the price of some rare old Technic components in new condition. Anyhow, this is more of a product by a Technic fan for other fans rather than a serious money making venture.

[2GodBDGlory]

23 hours ago, jxu said:

More expensive, but not prohibitively so. IIRC the original Shapeways cost was about $6, I could likely do it cheaper, and it could be much cheaper in bulk. That's comparable to the price of some rare old Technic components in new condition. Anyhow, this is more of a product by a Technic fan for other fans rather than a serious money making venture.

Okay, that does sound like a fairly reasonable price for a serious fan.