Instructables

One of the most difficult and yet common mechanical systems is a gear train. A great way to transmit mechanical power from one place to another or to increase or decrease power (torque) or increase or decrease the speed of something.

The problems are always that to make efficient gears needs quite a lot of drawing and mathematical skill as well as the ability to machine complex shapes.

For a lot of amateur work it isn't necessary to have maximum efficiency and therefore we can get away with a much easier to make, even with hand tools, system.

A gear is basically a series of teeth on a wheel.

http://automata.co.uk/gears.htm

provides a very good explanation of how gears work and how to work out gear ratios.

 
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Step 1: Formula and Maths (the bad news)


Formula for drawing and making gear teeth are all over the web BUT they seem, to the beginner, very complicated.

from http://www.engineersedge.com/gear_formula.htm

So I decided to simplify the issue and it works very well at both large scale and small scale. At small scale it works best with machine cutting with laser cutters for example when very small gears can successfully be made this way.


Step 2:


kimvellore6 months ago

I got the program Gearotic and it has changed the way how I draw gears it has made it so simple, Check it out.

protolabs2 years ago
if making gears is too difficult, you can use sprockets like I made here:
http://www.instructables.com/id/simple-wooden-sprocket-without-cnc-machines/

but good work rickharris
tilmen3 years ago
I'm intersted in making gears and I've read somewhere that gears are the hardest mechanical components to make without proper tools.Your instructable is good and teaching from this point of view.
rickharris (author)  tilmen3 years ago
Thanks - To make correctly shaped gears is a little more complicated - there are lots of on line calculators and explanations of why they are that shape.

This is a way to make gears at home that for low pressure system work quite well.

large size you can make with a drill and round file, smaller sizes really need some kind of machine to cut them. A laser cutter works very well as in my picture.

thanks again.
Nice article,

Just bear in mind, there are very good reasons why gears have the profiles they really do !
rickharris (author)  steveastrouk3 years ago
:-) Yes I know - BUT for much hobby use the sinusoidal gear if not heavily stressed works as well and is much easier to construct with very basic tools.

Remember for hundreds of years Windmill manufacturers got by with simple squirel cage and pin gears.
Jayefuu3 years ago
You'd like Mathias Wandle's gear generator Rick. Steve has it, it's brilliant.

http://woodgears.ca/gear_cutting/template.html
rickharris (author)  Jayefuu3 years ago
Yes I have seen that and used it - Works great and his wood work is fantastic.

There are other sites that provide gear drawing software as well - I believe inkscape has a gear drawing engine in it .

This is just a very simple way for someone to do it with basic compass and pencil tools.
SWV1787 Jayefuu3 years ago
I'm a big fan of Wandle's site it is defiantly worth looking at
brunoip3 years ago
Very useful.-