Posted by bills on May 23, 2015 at 09:55:53:
In Reply to: lorenz f600 posted by Wilson hong on May 16, 2015 at 13:02:07:
From other questions you've posted, I would guess you have cut spur gears.
Do you have an operator's manual for the machine? Not that a picture would be so complete, but basic operation would surely be covered. Look for section that would show example of helical cutting. If you find the section discussing helical gear cutting, I would be glad to determine the machine type and formula and help you use it.
I've only had data for "E" series Lorenz hobbers, and these are type "A" machines, which defines the type of differential formula. The type A differential formula expression includes gear lead, or number of teeth to cut. This differs from type B machines, where the differential formula is independent of teeth to cut.
Does your machine use dial feed or feed change gears? I ask, because the "E" series machines (type A) use dial feed.
Also, this website's gear FAQ page has many topics covering hobbing in general, and may be a place to start if you can't find a manual.
There is a table of hobbing machines in the FAQ, and at the bottom of that table is a footnote explaining A and B differential formulas and how they differ.
This subject might be more of a journey than a destinaton, but once you have the complete differential formula,
I think you will be close to your destination.
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