Brief Summary:

Purchasing robot parts in a surplus store can be a more economical alternative to buying from a retail sales vendor.  In addition to a savings in cost, learning how to put a robot together starting with just robot parts will improve your knowledge of robots. 

• The robot parts I found were specialized twenty tooth stainless steel chain sprockets and as is the law regarding purchases from a junk dealer, they had exactly two of the three pieces I needed.
• So far, all the feed back on this avenue of the robot part project was negative. The only saving grace came by quick interjection on the part of the sales man who assured me the chain required for 0.1475"-pitch was readily available from their warehouse.
• Robot parts catalogs available from several different retail parts suppliers that have engineering information in the back. These offer technical information on tooth spacing, flexion of chain under load information, and tooth strength information
• Later I went back and constructed a full 3-Dimensional model to integrate into the rest of the robot model. This allowed me to do a spatial check with all of the other robot parts modeled into the system letting me know that the part would fit.
• When pushed by the end of the robot arm that rides along side this tower. All of the pinions and drive sprockets are bearing mounted to help keep the power / torque transmission losses as low as possible.
• You may have noted that much of this work I take on, because - well, it's fun and the process of making my robot is as fulfilling as the finished robot will be.

To read the original article please click:

http://www.seattlerobotics.org/encoder/sep98/sprock.html