There are no external cams on this model.. they are built in. You will need to get a pattern card to show you how to move the levers and knobs to the correct position. Beware these tend to need quite a lot of elbow grease to get in perfect working condition and to have the built in embroidery until work as it should. I actually have one on my table now and have put 4 hours into it and will likely put several more hours. Don't force any of the levers or they'll crack.