Part 6. Functional demonstration, cam grinder lathe conversion. 

Thanks for showing that Tony. That was fun to watch. I bet you're having fun building it too. Nice job. A real logical & professional approach.

Always nice to build your own machines.

I'm really enjoying watching the process.

Good thoughts about the camshaft grinder! But I have a few points/hints. For the cross slide (and thus the spindle RPM): You have the acceleration of the cam at a given engine RPM. You can use that to calculate the maximum spindle RPM. You can use 1 m/s^2 as maximum acceleration of the cross slide. Thus, say cam acceleration at 3000 RMP (cam) is 6000 m/s^2 makes 0.5 RPM. The max. acceleration of the cross slide with 1 m/s^2 is conservative. But you certainly will have problems at 10 m/s^2. Also note, that there are some geometric distortions and thus the cam accel. is different to the wheel accel. Depends on the rocker arm or whatever your engine uses. F = m * a. Force (along the cross slide) is mass (of the wheel and its drive) times acceleration. Force is in Newton, mass in kg. 10 m/s^2 is about earth's gravity. You need a steady rest. You will have problems to get the cam running true near the center. 0.02 mm of runout is about what is allowed. And this already distorts the cam profile you grind. Not so much for the lift (who cares for 0.02 mm more or less lift), but for the acceleration and even more for the jerk. Keep that in mind. You need coolant. You need coolant as soon as you intend to take off more than a tad. The cam will heat up and expand and take off more, generate more heat, expand more and so on. Also the wheel will clog up and generate even more heat and pressure and push the cam shaft out of center (-> steady rest). This expansion will happen after a few seconds and then get disastrous within a couple of seconds. This is not a tool and cutter grinder where you come off without cooland when you pay attention. I hope you get the math right. The wheel's diameter plays a role as this influences the hight of the contact point that is also influenced by the shape of the lobe. And most of all, that is not what your rocker arm or flat tappet does move along. There are at least 2 transformations. Not wanting to talk you out of your project!

Very interesting, there are quite a few hidden complexities which you have raised. Like the imprinting of the patten into the grind by the motor using vee or tooth belt. I would not have thought of that. Do you have any good links to people wanting to start looking at adding power feeds (via motors) to small hobby lathes and mills. Starting off very simple mind you before then looking at computer control.

where do you find the time???

hope you will share your calcs on lobe profile design

Are most camshafts case hardened? I don't know. If so how are you going to deal with that