# Cutting a Cam Lobe



## cfellows (Jan 7, 2013)

This is a video I made of cutting a single cam lobe on a gear hub.  It uses a rotary table and a boring head.

[ame]http://www.youtube.com/watch?v=ohqO0GIdoLU[/ame]

Chuck


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## Cogsy (Jan 8, 2013)

What an excellent video! Thank you Chuck - I've been wondering how I was going to make decent cams for my Upshur builds. It was worrying me, but now I'm sure I can get it done.Thm:Thm:Thm:


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## Generatorgus (Jan 8, 2013)

Pretty neat Chuck.  I never thought to use a boring head for cutting a cam.
I have to remak the cams for my Wyvern, I think I'll  take a whack at it.
Thanks

GUS


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## OrangeAlpine (Jan 8, 2013)

Chuck, many, many thanks for the video.  All I need now is a dividing head with chuck and a boring head.  I do have the milling machine!

I do have some questions about the boring head.  How big does it have to be?  3"?  I notice that your boring appears to be shop made.  Is it?  If it is, could you enlighten the guy standing in the dark in the far corner?

Bill


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## starnovice (Jan 8, 2013)

chuck,
I am having problems wrapping my head around the math/mechanics of doing this.  As I see it a cam has to radius's connected with tangent lines.  This also means there are two center points one for each radius.  Yet you did your cutting from the same position for all of them, basically the center point for the minor radius.  I don't see how that made the other end the right size.  What am I missing?  Probably a lot. 

Pat


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## cfellows (Jan 8, 2013)

OrangeAlpine said:


> Chuck, many, many thanks for the video.  All I need now is a dividing head with chuck and a boring head.  I do have the milling machine!
> 
> I do have some questions about the boring head.  How big does it have to be?  3"?  I notice that your boring appears to be shop made.  Is it?  If it is, could you enlighten the guy standing in the dark in the far corner?
> 
> Bill


 
Thanks, guys, for the comments.  Bill, the dividing head is shop made.  Rudy Kouhoupt featured one very similar to mine in an issue of HSM some time back.  The dividing head doesn't need to be very big.  Most of the cams I've made only required a diameter of about 1 1/4".  You could actually make a special purpose tool to cut the cams. You don't really need the adjustable diameter afforded by boring heads unless you plan to make a lot of cams and want to vary the arc on the rise & fall.  A fixed diameter boring head with a swing of about 1 1/4" on the tool would likely be fine for most small cams.  If, for some reason, you wanted to flatten the rise and fall could always tune it with a file.

Chuck


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