Gears : was Re: Usefull Utility

--- In CAD_CAM_EDM_DRO@y..., "Smoke" <smoke@t...> wrote:

> Recent circumstances have required me to redesign the standard gear
>tooth
> profile.
> I couldn't machine them using CNC because the face width was to
>wide and I
> couldn't get an end mill in the required diameter with a cut length
>long
> enough to do the job.
> Once the first gear is drawn, all other gears have to be made
>individually,
> because the pitch diameter doesn't not change at a linear rate.
>Now THAT
> would be a lot of work if I had a large number of different sized
>gears to
> develop.

Smoke,
Just curious what size cutter and what face width are we talking
about here?
Could you not cut these with a conventional form tool and the blank
in a 4th axis.?
If you have redesigned then to suit a certain cutter size how have
you determined the correct involute and pressure angle?

As you say the pitch diameter doesn't change at a linear rate as the
true shape is an involute. Just as the sprockets have 5 cutters per
set gears have 8 per pitch and pressure angle.
I do have a full set of geometrically correct 14.5 and 20 degree
pressure angles gears in CAD format at 1DP which can be scaled to any
DP or Mod. The whole range from 10 teeth to 120 teeth in dxf and dwg
format if any of these will help.
Better you contact me off list if these will help.

John S.

>
> I used the CAD program for the redesign work. I'll be testing the

program

> to cut the gears on the CNC MACHINE at school next week.
>
> Smoke
>