Pushing the envelope - a BIG gear horizontally on the Taig mill

[Stephen Fornelius]

I'm doing a sprocket for a #25 chain for a clock I'm designing.  The issue is that the specifications of the chain establish the diameter of the sprocket.  For example, an 84 tooth gear is about 3 inches, and 84 tooth sprocket is 6 7/8". 

With the advice of Art, and products from Wildhorse Enterprises to extend the y-axis, I was able to cut a gear 6 7/8" diameter on a Sherline cnc rotary table horizontally.  This is about 1 inch beyond the standard table envelope.

This was impossible to do in a 4th axis because I would have had to jack up the rotary table about 2" and lose rigidity, the rotary table would have been offset too far forward, and I would have needed some significant backup plates to prevent distortion if a fly cutter was used. Plus I need more experience doing something like this of course.

[ArtF]

Stephen:

Glad to hear it worked out..Large gears are always difficult for us Home hobby guys...

Art

[JustinO]

"Stay within the lines."

Stretching and extending the limits is great fun -- I've had parts on my Sherline lathe that weighed more than the lathe.