Drawing Gears with a Compass (simplified method)

Please turn on the captions for extra instructions!
Hi everyone, I wanted to make a video about drawing out functional gears with a compass. It goes over the basics of reference diameters and modules, but please keep in mind that it is a simplified method (specifically one that doesn't use any software or power tools). If you're looking for a video that goes over pressure angle and profile shifting, there are other videos out there that cover it.
Additional Notes:
- Some definitions: the module is the size of the tooth, the reference circle is where the spacing equals the tooth thickness, the root circle is basically the gear without its teeth, the tip circle is the gear without its spaces, and the center distance is the distance between the centers of the gears.
module = m
tooth number = z
reference diameter = d
root diameter = df
tip diameter = da
- Everything is measured in millimeters in this video
- Some common modules to choose are: 1, 1.5, 2, 2.5, 3, 4, 5, 6, 8, 10. . . (it's called the first series and these modules are used because they normally make calculations less messy)
- For anyone wondering, I purposefully made deciding the module as the first step, so that people that do it by hand can make sure they're able to cut out the teeth with the material they're using.
- You might have noticed that this method isn't great for getting exact gear sizes. Of course, the smaller the module is, the more accurate the tip diameter becomes, but it also gets harder to cut out the gear by hand. This method is still pretty good for casual projects, but not as much for projects that required extreme precision.
- If you end up cutting these out with cardboard and making them with paper, give the gears some depth so that they don't slip as easily.
Anyway, thanks for watching! If you have any questions or suggestions for improvement, please leave them below in the comments.

[@addibbaaj2]

I'm an industrial design student and this video helps me so much! Not everyone has access to 3D printer and maybe the only best bet we have is creating these type of gears with PVC foam. I love you for this, thank you so much!

[@logicalsolutions73]

Had studied gear design during my mechanical engineering course ages ago and had forgotten it... thanks for sharing this video 🙏🏻

[@peporiol782]

Great "Hello World" in spur gears design! And its amazing the way handle the pancil!

[@xxriley1557]

YOU NEED MORE SUBS 😭😭UNDERRATED

[@TurkishEdition1781]

So many many many thanks mate i dont know anything about gearwheells until saw your video thanks mate

[@ian9050]

this is so good and helpful! thanks a lot!

[@ChoaibElmadi]

Thanks a lot that was clear, simple and helpful

[@markbailey5393]

Inspirational. Great work. Thanks, mark.

[@tristanbluhm]

Finally an easy way to understand how to make gears I tried looking up a template but I could not find what I need now I have something

[@muymuh7319]

Thank you for making im arpشكرا جزيلا لم ار مثلك فى السرعه والبساطه والاحتراف

[@ronwoodmarcenaria4936]

Great Job. Belo trabalho. Parabéns

[@mauricioschemberger8067]

Ficou muito bonita a sua explicação! Matemática, Geometria e (essa linda) Musica! Poesia!

[@zekstra78]

Not perfect, but simple and easy for everyone and functional. Thanks!

[@nattapolpunpaen2539]

ขอบคุณครับสำหลับการสร้างแบบ😊

[@LAUGHWITHLORDSUPERSTAR]

Nice 😊

[@iuliangrosu4663]

Thanks

[@satpolpepe7045]

Wow... Keren 👍

[@BongoBaggins]

'Pair of compasses'. A compass points north.

[@alashiritoheeb8888]

What does the Z and M signifies?

[@cressyism]

Z signifies the number of teeth on the gear, and M signifies the module, which correlates with the size of the tooth. Everything is also explained in the captions and description, thank you for stopping by!

[@udayseul1535]

1:25 , what exactely we have to do , how do i get that measurement.,. from where ,,, please help

[@cressyism]

There is no exact measurement required, the compass only has to be past the halfway point (and you can tell visually) for the halfway point to be found. Hope that helps!

[@udayseul1535]

@@cressyism thank youo much for you replay , means a lot , god bless you

[@prashitvora5773]

0:12

[@vesnacordeiro5857]

I don't understand the part about dividing the circle. Can you please explain it in more detail? I would really appreciate it!

[@udayseul1535]

Can you be more specific??

[@cressyism]

Sure, is there a specific part of dividing the circle? There is a video here, kzbin.info/www/bejne/jV7EpXSvmKZjh8k, that describes in detail how to divide a circle with a compass into almost any amount. But in the case where you only need to divide a small section in half, the compass must be adjusted anywhere past the halfway point (something you can judge visually), and the intersection of the two arcs can be used to determine the halfway point. Hope that helps!

[@ssupersairot555]

Can you explain how -2.5 and +2 from? (df,da)🥺

[@cressyism]

These are measurements often used for a "standard" gear tooth shape, and there are other formulas out there for custom tooth shapes, but these are pretty easy to use for casual projects.

[@udayseul1535]

1:24 . Can any kindle help me , what exactly is going, i didn't understand that part.

[@cressyism]

Definitely, in that part, to divide the section (since tooth thickness and pitch on the reference circle are equal), the compass is adjusted to be past the halfway point (that is the only requirement, being exact does not matter), and once the arc is drawn from both points, the intersection can be used to mark the halfway point on the reference circle. Hope that helps!

[@udayseul1535]

@@cressyism thank you so much for clearing my doubt🙂😇

[@handlol]

the variable z (number of teeth) must be a multiple of 4, right? 🤔

[@cressyism]

Not necessarily, z can be any number, I think I just happened to choose two example gears that had the number of teeth be a multiple of 4

[@handlol]

@@cressyism yeah after some experimentation I made some 6 teeth gears along side the 8 and 12 teeth gears in your vid. your vids are great 🌟 keep on sharing knowledge cuz it helps people

[@user-uu9lx8no4d]

Where is module...

[@wolflotbrook]

nece👍

[@anuradindin4867]

ड्यूल 2 या फिर 2.25 फर्स्ट गैर टिथा 20 सेकंड गैर टिथा 60 प्रेशर एंगल निकाल दीजिए

[@andreavela1433]

how do i know the reference diameter size to divide 40 teeth?

[@cressyism]

oh, that depends on what module (tooth size) you choose. If you're cutting it out by hand, I'd recommend a module around 5mm (though anything works). The reference diameter is represented by the letter d, and the number of teeth are represented by z. So, d = m * 40. Assuming that you were using a module of 5mm, d = 5 * 40 = 200mm. In that case, the reference diameter would be 20 cm. The rest of the formulas are at 0:19

[@andreavela1433]

@@cressyism let's see if I understand... if I make a gear with 40 teeth with a 5 mm tooth I have to make d 5 x 40 and it gives me 200 mm... then the df (40-2.5)x5 which gives me 187, 5 mm... then (40+2)×5=210 mm da... it's correct?

[@cressyism]

@@andreavela1433 Yep! That's pretty much it, looks great!

[@andreavela1433]

@@cressyism thanks for the replies!!! then i will try to draw it i hope it is accurate enough to build a pendulum clock... the 40 tooth gear is the biggest one in my project and the tooth size will be 1cm and the other gears maybe only 5mm... the only thing is that I don't know what that 2.5 in that formula df means and the 2 in that formula da... the pressure angle or the displacement of the profile doesn't interest me... the important thing is that they mesh perfectly and that I can divide the circle perfectly which is critical to gear construction...your gears look perfect... i am italian and use google traductor to write you language

[@cressyism]

@@andreavela1433 no problem! The 2.5 and 2 give the shape of each tooth that helps them mesh together without getting jammed. Using your example above, the space from the df to d is 12.5 mm, while the space from the d to da is 10 mm. You might notice a ratio, 2.5 : 2 is the same as 12.5 : 10. For the gears to mesh together perfectly, just make sure they all use the same module. As for dividing the circle, I'd say that the most accurate method is to use a protractor, because it becomes harder to use compass geometry the more teeth your gear has. You can also find an arc of a circle and its corresponding chord, but everything has to be very exact for that to work. I'm still improving my own skills myself, and it's nice for you to stop by! I'm excited to see how you're project turns out!

[@pigghedd8245]

Why is the M value relevant

[@pigghedd8245]

Is it that gears need equal M values to work properly?

[@pigghedd8245]

M value = module length. Thanks.

[@minarrahman1433]

Make it in 3cm

[@corncobjohnsonreal]

The way you hold a pencil makes me really mad for some reason

[@cressyism]

You will see more of it in the future.

[@user-rq9po2zv4k]

Дякую вам за працю 😊❤

[@ESCORTS_DIY]

Video is 2x speed

[@EmihleMaphumulo-ps2zx]

And also thanks for nothing now I'm gonna fail my project

[@samanthasanjeewa8932]

👎🤬

[@AsterFoz]

I came here i watch a video about gears, not to learn about your music preferences? Cant you just talk and explain like a normal human being instead of adding subtitles and music that hasnothing to do with the video's topic?

[@vesnacordeiro5857]

I came here to learn from comments, not to listen to karens arguing here.

[@margovaughan1423]

I love this music!