Question about gears and chains

[paupadros]

Hello guys! I've recently started incorporating Technic into some of my builds and how stumbled upon a little issue which I hope you could answer:

In the modular Detective's Office, there's a 24-tooth gear (part 24505 https://brickset.com/parts/6133119/gear-wheel-z24) that holds a 3-wide chain (part 6047885 https://brickset.com/parts/6047885), which can hold plates. In the Detective's Office, this is used in the rooftop water tank. My question is, would this work with a bigger gear? I'm pretty certain the biggest gear in the Technic system is the 40-tooth one (part 6195314 https://brickset.com/parts/6195314/gear-wheel-40t) and I'm almost certain the chains and such gear are compatible. If anyone has such gear, will it work? Which diameter does the 40-tooth gear have?

Might be a rather dumb question, but trying to wrap my head around Technic is not at all the easiest thing!

[Bogdan Valceanu]

It will work. The small chain and small tracks work with 16t, 24t, 40t gears, and even with 8t, but the 8t gear is pretty small.  

[Void_S]

26 minutes ago, Bogdan Valceanu said:

It will work. The small chain and small tracks work with 16t, 24t, 40t gears, and even with 8t, but the 8t gear is pretty small.  

Correct, the chain works with old non-bevel gears (with rectangular teeth). I can't find the 40T's size now but can measure it and share in a couple of hours.

As for 8T, please note that it works only with the old version (3647), as the new one (10928) has stiffening ribs that don't allow the teeth to engage the chain links.

[Splat]

All Technic gears (since about 1977) are designed to work with each other, so the gear teeth have the same pitch allowing them to mesh together, and this constant pitch also means that the chain links will work on all of the gears that others have mentioned above.

Technic gears can generally be divided into two categories:

1. Gears with skinnier square teeth (8, 16, 24, 40), and
2. Gears with fatter rounded (bevel) teeth (12, 20, 36).

The chain links will work with all of the skinner square teeth gears, except the newer 8 tooth gears as Void_S mentioned.

The size of a gear can be calculated by the number of teeth divided by 8.

8 tooth gear / 8 = 1 stud
16 tooth gear / 8 = 2 studs
24 tooth gear / 8 = 3 studs
40 tooth gear / 8 = 5 studs

Since the teeth of one gear overlap with the teeth of the adjacent gear, the true diameter is a little bit bigger than these values.
For example, the true diameter of a 24 tooth gear = 3 studs + the width of a gear tooth, meaning that it won't fit in a 3x3 stud hole, but it will mesh with another gear next to it.

The number of teeth can also be used to work out the spacing required between gears: (gear1 + gear2) / 2 gears / 8 teeth.

8 tooth gear to 8 tooth gear: (8+8) / 2 / 8 = 1, meaning that these two gears should be 1 stud apart (center to center)
24 tooth gear to 40 tooth gear: (24+40) / 2 / 8 = 4, meaning that these two gears should be 4 studs apart (center to center)

If you are trying to mesh two gears that are diagonal from each other, the same rules applies but you might have to use some Pythagoras geometry to work out the distances and gears that will fit, or use Sariel's gear calculator: http://gears.sariel.pl/

[paupadros]

Thanks for all your replies! Coming from the studded world, gears are a bit hard for me, but thanks! Extremely grateful for the measurements and this trick for centre to centre distance @Splat! I'll ask again if I have any more issues