Cam Grinding Hypothetical Design Concepts

[GreenTwin]

As I mentioned, using the drawer-slide style design is to make the equations linear, instead of having things swinging in arcs.
And I mentioned that this design it more to understand the calcs, whereas Peters design would probably be a more practical style to actually build.

And I was thinking something like what is used on a 3D printer rail, whatever that is, since those are pretty accurate, but they don't have much force on them.

Mainly this is an exercise to linearize the calcs so I can understanding what is happening.

I read the white paper, but I don't have a good feel yet for that method.

Bottom line is that if I can understand the equations, then I could build or design one in any format.
I can see I still have a ways to go to begin to understand the process.
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[Jasonb]

You can't really make it linear as you need a reduction from master to actual cam.

If you look at Charles's machine he made the master 5 times larger than the actual cam he wants. The position of the blank from the pivot is 1/5th the distance of the master from the pivot. So if his master cam has a lift of 2 1/2" (5 x 1/2") it will also lift the end of the arm 2 1/2". Using scholboy geometry it should be obvious that the cam blank will only be lifted 1/2" above the wheel

If one really wanted you could have slots in the pivoting bar and then have the master's axle and the blank's axle move on vertical guides but I suspect all the extra backlash in such a complex setup would create more errors than any very small ones that may exist due to things moving in an arc.

 

[GreenTwin]

I don't think I have seen that photo.

Yes I agree that adding more backlash would not be worth the amount of error saved.
I think the amount of error would be tiny.

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[Charles Lamont]

... more errors than any very small ones that may exist due to things moving in an arc.

Thanks, Jason - clearly explained - except that (and I noted your use of "may") actually there is NO error due to things moving in an arc. Because the master follower is 5 times the radius of the grinding wheel, and the pivot point is correctly placed, the putative 'errors' all cancel out.

For Peter's 1:1 design, unless there is some fancy design put into the master cam, and unless I have misunderstood it, I think, but I am not sure, that for correct geometry the follower wheel or shoe should be the same radius as the grinding wheel. (There's a statement full of caveats.)

GreenTwin - forget about equations, you just need to understand the geometry. No trigonometry, no quadratics, no calculus. Pencil and paper sketches and Euclid are all you need. I would add that it took me a quite a bit of thinking and drawing before I had it sussed.

 

[GreenTwin]

for correct geometry the follower wheel or shoe should be the same radius as the grinding wheel

That is an interesting statement, but not really one that seems logical give the difference in size between the ground cam and the follower wheel. Seems like it would be a ratio of the size difference.

Yes, its just geometry, but seems a bit tricky.
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[Jasonb]

There is logic in it, as the makers of full size cam grinders have worked out. Look at the size of the (in this case round) follower and compare it's diameter to the grinding wheel.



There is an old thread on here about creating a master wheel of the type shown in that video and on Peter's machine

 

[GreenTwin]

That is a good video.
I will have to watch it several times.
I learn sloooooooooowly.

I had to look up his company location, to figure out that accent.
Seemed pretty deep south when I heard it, almost like an Alabama accent.
He is out of South Carolina.
I am in the Mid-South, and I only made one talking video years ago; that cured me of talking in my videos, LOL.
Myfordboy does not talk in his videos either, so there is that.

Very nice equipment he has.
I tend to forget how big things like NASCAR are in the states, and how many people like Powell Machine it takes to support activities like that.
Drag racing use to be very big in this city, and I use to hang with a buddy who was constantly building Chevy racing engines; mainly 454-LS6's and 427-L88's.

Still watching the Powell video and learning.
He almost makes it all seem simple, but I know better.
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Edit:
I have a client who use to attend NASCAR at Talladaga, and he tells some pretty wild stories.

Edit02:
I had the opportunity to visit a Caterpillar rebuild facility in Mississippi about 20 years ago, and that was quite a fascinating place.
They repaired cracked blocks and heads, and used spray plasma to build up surfaces.
Most impressive operation.
They had some massive grinding wheels.
I need to look for my photos.
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