Involute gear--scale down--print. Possible replacement for a fiber clock wheel?

[LittleWatchShop]

About done with this Seth Thomas Electric clock.  It has several fiber gears.  On another forum, it was mentioned that these cannot be sourced.  I do not have a broken one, so I am not in a hurt to make one!!  However, I was curious.

FreeCAD has an involute gear toolbox.  Once you set the number of teeth, most of the work is done for you...including setting the diameter of the wheel/gear.  The fiber gear in this clock has 80 teeth and is 40mm diameter.  The toolbox generates an 80 tooth gear with 80mm diameter (roughly).  It hit me yesterday...just scale it in the slicer!!

Here is the result.  I am not going to test it because this clock I am fixing is already in the case and in test mode.  However, now that I have more or less proven the concept, I will have this in my back pocket in the future.

 

 

[jdm]

19 minutes ago, LittleWatchShop said:

FreeCAD has an involute gear toolbox.  Once you set the number of teeth, most of the work is done for you...including setting the diameter of the wheel/gear.  The fiber gear in this clock has 80 teeth and is 40mm diameter.  The toolbox generates an 80 tooth gear with 80mm diameter (roughly). 

There must be another parameter called Module.  OD = M * (Z + 2).  If you scale down all goes to hell. Another way is digitize profile and clone across circumference, as this guy did. https://www.thingiverse.com/thing:3448271#How I Designed This
In the end, his gear works for me, actually saved a lot of aggravation obtaining an original one.

 

[LittleWatchShop]

Digitizing the profile is a good idea.  I see what the guy did more or less (I don't use Fusion360--perhaps I should). I will dig deeper when thee is a genuine need.