Making a crossover cam

[Chaffe]

Interesting read, We used to make something similar (on a longer scale) for guiding a wire rope onto a drum, very tricky to get working smoothly, without sticking. Any pictures of the stylus itself? a lot of work in that too IIRC.

 

[Dave G]

A picture of the stylus attached to the shuttle. The roller follower can be seen also.

 

[Dave G]

Another picture.

 

[BillTodd]

Ingenious use of a self reversing screw

For those who haven't seen one operating, this is longer than Dave's but it shows the principle:

 

[Dave G]

Thanks Bill, I love the animation. I'm still working on posting a video but with not much success so far. My computer skills are growing since hanging out with you guys but I still have alot of room for improvement. As to my engine, I have a tendency to gravitate towards things that are out of the ordinary. Must be a mental defect. I've been working on a design for a twin cylinder engine using this same device but haven't quite figured everything out yet. Might be my next build, I don't know yet.
Take care, Dave

 

[Captain Jerry]

I have several of these cam/screw in my tackle box. They are used to operate the level wind feature on fishing reals.

I am really more interested in the engine application of the cam and its success at higher speeds. I know you will give us a video soon.

Waiting.....

Jerry

 

[Chaffe]

top notch work there on the follower

 

[Swede]

That is brilliant! :bow: I am continuously amazed at what can be fabricated that LOOKS CNC but can be done manually. Small inline cam-shafts are another item where clever fixtures with pins, indexes, etc can be used to make a very special shape...

This camshaft (deHavilland 1/6 Cirrus) was generated by a clever rotary fixture and a 3/8" end mill, described perfectly by Eric Whittle in his SIC construction article. Cams demand some serious thought, but it is always possible without CNC.

Thanks for sharing, it's bound to give people ideas.