Simple Guide to Making Sprockets

Sprockets are one of the most important parts of many mechanical devices such as automotive and automation technologies. They aren’t expensive to buy from; in fact, Mcmaster-Carr sells them at a reasonable price. But for those of you who love building things from scratch, or who need a specific sprocket that you can’t find in stores (or that’s too expensive for you), this guide will show you how to make them! This method for manufacturing them is focused on those who have simple diy cnc machinery that can’t perform the more complex tasks of current commercial cnc machines. This process is also handy for those who are inexperienced at working with cnc machinery.

Most home-built cnc machines use a driver program such as Mach3, which is what I will be using in this guide. I’m also going to be using CAM software called MASTERCAM, which has a post-processor in it for generating G-code compatible with Mach3. For those of you that have Mastercam but don’t know where to find a compatible g-code post-processor for Mach3, I found mine here (this is the link for downloading the file):

http://cnc.novalab.org/files/MACH3B_for_MC9.zip

For the sake of keeping things simple, This guide will show you how to make a #25 1”, 11 tooth sprocket. If you want to make a different sized sprocket, you can use this guide as a basis on how to construct your sprocket.

This guide will only show you how to make the sprockets with a cnc mill/router that uses Mach3 driver software. The process is pretty straightforward, though, so using this guide with other cnc mills/routers should simply require small adjustments to the process to work properly.

This guide will not show you how to create the 3d part on solidworks. If you want to know how to do that, here’s a great link that helped me:

http://www.gearseds.com/files/design_draw_sprocket_5.pdf

Note: you must at least have a cnc mill/router AND a metalworking lathe (preferably a cnc type). You could try using a woodworking lathe, but I advise you only do that if you plan to make wooden sprockets with far less precision.

I AM NOT RESPONSIBLE NOR LIABLE FOR ANYTHING THAT HAPPENS IF YOU DECIDE TO USE THIS GUIDE! REMEMBER TO USE COMMON SENSE AND GENERAL SAFETY PRECAUTIONS WHEN OPERATING MACHINERY AT ALL TIMES!

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Step 1: Tools/Materials Needed

Here are the Materials you’ll need:

Tools/Machinery
-A CNC mill/router that uses Mach3, and has a vise for holding the stock.
-A 1/8” cutting diameter end mill and a ¼” cutting diameter end mill
-A CNC lathe with manual control OR a metalworking lathe
-A Drill press
-A ½” diameter drill bit with a tapered end. For extra precision, use a counter-boring/step drill bit with a small diameter of ¼” and large diameter of 1/2”. You can also use a ½” drill bit countersink that attaches to a ¼” drill bit. Using these REALLY HELPS and makes a huge difference in the quality of your sprocket.
-A hand saw AND a hacksaw (or a jigsaw with both wood and metal cutting blades)
-A 1/8” drill bit (Size can vary as it is simply for predrilling the holes for the screws)

Parts:
-One 1-1/4” diameter aluminum rod (length must be at least ¾”)
-One 2”x3”x0.75” block of wood (Block 1)
-one 1”x3”x0.75” block of wood (block 2) (size can vary as long as it is 0.75” thick and at least 2-1/2” long)
-Two 1-1/2” screws (size can vary as long as they are ½” longer than the width of the 2nd block of wood on the list.)

Software:
-Mach3 licensed version
-Mastercam with a Mach3 post-processor (optional)
-A 3D CAD program such as Solidworks (optional)