GearHeads Corner

Hi,

I remember there used to be the info regarding the stock profile to prepare for a bevel gear. Can't find where it is in Gearotic Thoughts..

Dan

Hi Dan:

  Put out a dxf of the bevel and youll find it includes a drawing of the bevel blank.. though
I still havent done any code to allow cutting them. The problem on my end is to do it simply enough
that people will do it, and thats hard unless you have 5th axis, most dont. GMv1 puts out code for a tilted
cut of a bevel, but I dont think its ever been tested.
Art

Hi Art,

Thanks. Just want to try cut in without a 4th axis. Going to output as STL to a CAM and generate Gcode.

Dan

Dan:

Let us know how it works out.. :)

Art

Hi Art,

Cut a couple of gears. Used epicycloidal tooth profile, as didn't have an end mill small enough to make the desired gears. They are 20 teeth and 10 teeth module 1. Cut with a 1mm end mill. They mesh, but looks like they have an awful lot of backlash (which the simulation confirms). However, will have to actually mount them to get the real feel of it.

Dan

Dan:

Seems they worked out well enough to work, but the teeth seem thin. If sim looks the same Id check the tooth width
isnt set too small. Othewise ID think the tool was ever so slightly too large...

Art

Art,

Simulation looks exactly the same. Changing the tooth width doesn't appear to affect this gear type. I could probably fool the CAM software by defining a larger tool diameter than actual to get thicker teeth.

Any idea how to figure the mounting distance of bevels?

Dan

Dan:

Strange.. are they epicyclic tooth profiles by chance? I kinda wondered on first look. ..
Epi's are designed to be loose.. its part of their appeal...

  Mount distance can be seen as the pitch circle radius from center of opposing gear.
(Just up frmo a gear laying flat instead of sideways..)

Art

ArtF wrote: Strange.. are they epicyclic tooth profiles by chance?

Yep, they are. I said that in the original post ;)

Now trying to cut involute and encountered a srtange display bug. Guess, will start a new topic for that...

Dan

Dan:

Sorry, I missed that point. Epi's are pretty loose by design. (Ill wait for your new topic. lol )

Art

ArtF wrote: Mount distance can be seen as the pitch circle radius from center of opposing gear.
(Just up frmo a gear laying flat instead of sideways..)

How is the pitch circle defined for bevels? The on-screen info says "Center Distance (from outside pitch line): 20" - what does it mean?

Dan

Dan:

  It means the rear point of the gear where the two bevels touch one another to the center..

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from the bottom right to center of the above glyph would be the outside radius
of the bottom bevel. ....

Art