Step 7: Part 6: Milling your sprocket
2) Place your template top side up in the CNC vise so the ends of the template fit snug up against the ends of the vise and tighten greatly (but not too much). The amount you tighten is crucial for keeping the sprocket blank in place while it is being milled.
3) Replace the ¼” end mill with the 1/8” end mill. Don’t worry about length, as it will be corrected in step 4.
4) Move the y-axis ¼” from the center origin and gently lower the z axis until the tip of the 1/8” end mill is touching the top of the sprocket blank. Click on the 0 z axis button on Mach3 (circled in red), but DON’T press the 0 y axis or 0 x axis buttons (circled in orange in the picture). If you do, you may have to start all over!
5) Raise the z axis slightly, and start the spindle. It is highly recommended that you spray a cutting fluid (WD-40 works too, but not recommended) on the blank if your machine doesn’t have an automatic cutting fluid dispenser.
6) Click on Cycle Start to start the program, and wait until your CNC mill has finished milling the sprocket. If something happens, make sure you press the emergency stop immediately (or press the space button on your computer keyboard). Don’t worry if you have to the axis; as long as your sprocket blank stays in place, you will be able to automatically go to the last known position of your sequence before resuming the cycle.
7) Once your CNC mill has finished the cycle, turn off the spindle (raise the z axis if you have to) and remove the template. Wash it down with water until most of the debris is gone and remove your finished sprocket from the template.
Congratz! You’re finally done!