How to make gears easily

Step 4: Working out the size of everything

2.We can now easily sort out some simple maths to make our gear

• a. How big/small do we need the gear teeth to be, (diameter) - The smaller the gear the smaller the teeth need to be.
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• b. All the teeth that are going to mesh, (connect),  together must be the same size so calculate your smallest gear first.

3. Lets start with a gear tooth size of 10 mm

I want a gear with 10 teeth on it so the circle will be 10 x 10mm round (circumference)= 100 mm

To draw that circle I need to find the diameter so I use a bit of maths and a calculator a divide the circumference (100 mm) by Pi = 3.142

This gives me a diameter of 31.8mm I can draw this with a compass and then fit exactly 10 circles 10mm diameter round it with my compass.

If your able this is easier to do with even the most basic drawing software. If your using software you should be able to rotate the tooth circle round the main circle and will need to know how far to rotate each tooth - This is easily calculated by 360 deg / the number of teeth so for our 10 tooth 360/10=36 deg rotation for each tooth.