Hi All,  I found that the hardest part of designed the gear was
creating the profile of the tooth.  After examining quite a few gears,
both new and old, I arrived at the design in the pictures.  I've used
this tooth design to have a number of sprocket gears manufactured using
CNC, 3-D printing, and regular machining.  So far, they have all worked
well.

At Shapeways, it cost less than $10 to have this gear made out of their
'Strong & Flexible' plastic (nylon based) and just less than $80 for
aluminum.  I asked Dave Krall for the exact dimensions so I could
create an exact duplicate, but he said he was already working with
someone else on the project.

Musically,
John A Tuttle
Player-Care
Brick, NJ, USA

 [ 26-tooth ladder chain sprocket 1
 [ http://www.mmdigest.com/Attachments/18/04/26/180426_083447_26-tooth-sprocket.jpg 
 [ 26-tooth ladder chain sprocket 2
 [ http://www.mmdigest.com/Attachments/18/04/26/180426_083447_26-tooth-sprocket-1.jpg 
 [ 26-tooth ladder chain sprocket 3
 [ http://www.mmdigest.com/Attachments/18/04/26/180426_083447_26-tooth-sprocket-2.jpg 
 [ 26-tooth ladder chain sprocket 3
 [ http://www.mmdigest.com/Attachments/18/04/26/180426_083447_26-tooth-sprocket-3.jpg