Gear Cutter Question

I found a reference that said the same though it sounds illogical. One might expect the most accurate to be one in the centre of the range. Must be something to do with the approximations made.

With a quoted useful range it makes sense to use the one quoted for 20 teeth. It will be interesting to see what the experts have to say and any explanations offered.

Henry

In article , mikecb1 writes

I'm no expert - never cut a gear in my life, though I've read up on it in preparation to trying it soon. I wonder if the issue is one of interference. The small gears (or more precisely, those with least teeth) have gaps between the teeth which are greater in angle than those with more teeth, to allow the opposing teeth to mesh, but not interfere, over a larger angle of rotation. For a gear with very many teeth, its angular rotation from start to finish of contact is small, and for a rack of course it is zero. By "greater in angle" I guess I mean "has more cut away from the full profile of the rack form with straight-edged, sharp-cornered trapezoidal teeth at the nominal pressure angle".

A cutter which is perfect for an n-toothed gear will allow non-interference for n+1 teeth or more, but for n-1 teeth it could allow interference between teeth.

...Unless of course someone with some actual useful experience or knowledge points out the error of my theory.

David

That's exactly what happens. If you use a cutter for a gear with a smaller number of teeth than it's rated for, you will get interference. It there is no alternative, a slightly larger between centres distance or greater depth of cut will be required to restore workable meshing. DAMHIKT ;-)

Mark Rand RTFM

David & Mark

Thanks - that makes perfect sense.

Mike

Mike