How can I make my own cam grinder?

I have it in my head that I'd like to try to grind my own camshafts -
starting
out with a Briggs & Stratton motor. How can I make my own Cam
Grinder? Any
online plans? Anyone willing to walk me through it?
Thanks,
Jay
Reply to
KnuckleBuster
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I saw a small cam grinder that worked off a pattern and was chain driven, as I recall. Home built affair, and it worked very well. A grinding head much like a tool post grinder was used to grind the lobes. I have a picture or two if you'd like to see the concept. Let me know on the side and I'll send them to you.
Harold
Reply to
Harold and Susan Vordos
The question I'd like to ask: Do you really need to grind them? I have milled some lobes and they look very nice.
Nick
Reply to
Nick Müller
KnuckleBuster wrote in article ...
starting out with a Briggs & Stratton motor. How can I make my own Cam
Grinder? Any online plans? Anyone willing to walk me through it?
There was an article in Model Engineers Workshop within the last year or so about building a cam grinder that followed a master cam to produce cams for model engines.
You might be able to take the concept and blow it up to the size you need......
Perhaps you should pick up a copy of the magazine and inquire about past issues.
Reply to
*
That sounds exactly like what I'm looking for! I've seen a couple of pictures on the web, but I'm not the best at reverse engineering. If you could send me those pictures it would be great. I'll try to figure something out.
Thanks, Jay
Reply to
KnuckleBuster
I saw, and admired, this home brew cam grinder at NAMES last year.
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This page and the next are pictures of the machine.
Errol Groff
Instructor, Manufacturing Technology H.H. Ellis Technical High School 613 Upper Maple Street Danielson, CT 06239
New England Model Engineering Society
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Reply to
Errol Groff
They all have two problems in common: 1.) Where does the master lobe come from? 2.) The disk's axis has to be on the same plane that is built by the grinding disk's axis and the axis aróund which the disk swings. In the apparatus shown, the feeler (right of the disk) has to have a proportionaly bigger diameter than the grinding disk. If not, you get distortions of the grinded lobe.
Nick
Reply to
Nick Müller
I don't have a milling machine, so milling lobes is out of the question for now. I've been puzzled by the setup of machines like the one from the NEMES show - where does the lobe pattern mount and how do you know how big to make the pattern? Wouldn't, as the grinding wheel wears down, need a different size lobe pattern? I think it would be fairly easy to set up, but then I think about the follower setup for the pattern and it throws me off....
Thanks for the input so far! It's got me thinking.
Reply to
KnuckleBuster
It is the front axle that is driven by the (sloppy) chain.
This construction isn't the best of all. There is an other construction that uses a master lobe that is 10 times the original size. The NEMES construction only has a master with a bigger base circle, but the lift is -guessing by the photo- only 10% more. Much harder to make the master lobe precise. The other construction uses a pantograph and has a 10 times bigger master. You can file the master out of sheet metal.
Yes and no. It depends on the wear. But in principle, a worn disk needs a new follower.
The bigger the difference between the theoretical and the real relation between follower diameter and disk diameter, the more distrortions you have. The "sharper" the lobe, the more distortions.
In production, they use _huge_ disks when they do copy cams. But I think, that more and more cam grinders use CNC. Especially with the hollow chests of some lobes.
I have seen production cams that were grinded more like a shaper works. They had quite some facetts and not just a single smooth surface. But that was in a KIA. :-))
With the macro I wrote for my homebrewn DRO, it takes about 15 minutes to mill a single lobe.
Nick
Reply to
Nick Müller

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