# eureka relieving tool



## gmcken (Jun 22, 2014)

Has any of the members here made or used the Eureka relieving tool ?  This tool allows a person to make cutters to cut gears..  Any drawings or information would be helpful


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## Frank Ford (Jun 22, 2014)

I understand that drawings are in Gears and Gear Cutting by Ivan Law:

http://www.bookdepository.com/Gears-Gear-Cutting-Ivan-Law/9780852429112


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## gmcken (Jun 22, 2014)

Thanks for the information, just ordered the book


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## Frank Ford (Jun 22, 2014)

Thanks for posting the request - it reminded me of that tool.

I just ordered the book, too!


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## george wilson (Jun 26, 2014)

Is this a relieving tool that shunts the compound in and out as the work revolves,so you can make milling cutters,etc? It is geared to the gear train on the back of the lathe. If so,I might get the book.


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## DMS (Jun 26, 2014)

There is an eccentric shaft that is driven my the lathe spindle, the cutter rides on a carrier, and a ratched indexes the cutter on each rotation of the spindle. Pretty cool design. Here is a video of one in action

[video=youtube_share;Wg0V36H6HsU]http://youtu.be/Wg0V36H6HsU[/video]

Another guy adapted the design for relieving hobs

[video=youtube_share;kJ8kyC_bpHs]http://youtu.be/kJ8kyC_bpHs[/video]

Kind of hypnotic. I have the Law book and recommend it. Even if you have only a passing interest in gear systems, and don't plan on building eureka, I highly recommend the book. It has the clearest description of the cycloid system I have ever read.

As an aside, you don't need eureka to relieve cutters, you can do multi tooth cutters with simpler fixtures. I think eureka allows you to get higher tooth count cutters though. Here is a description of the method I am talking about:

http://www.deansphotographica.com/machining/projects/multipoint/multipoint.html

I don't think you could go more than a 4 tooth cutter with this method, whereas with eureka though should be able to do many more.


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## gmcken (Jun 27, 2014)

Thanks for the feedback.  I have the book ordered an waiting for it to arrive. I have made several gears and now have an interest in making the cutters to make more gears.


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## george wilson (Jun 27, 2014)

Pretty neat!!


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## ddmunroe (Jun 28, 2014)

A very unusual way to relieve a gear cutter ! )
For any or you that don't have the Ivan Law book yet this video gives good insight into involute gear design and purpose.
There are 4 parts to this series.
https://www.youtube.com/channel/UCnQ4q4hnLUGmguugOtsXKbg/videos

[video=youtube;A3X8cuJKyns]https://www.youtube.com/watch?v=A3X8cuJKyns[/video]


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