There exists an option for the 23 Frame SM motors denoted by "T", fitting into the part numbering scheme as follows:
This first "T" in this part number specifies a 1.25" shaft length and a .125" square key. This option is only available on a size 23 SM motor.
As of 2007, this is not available as a standard product but can be requested as a custom.
updated nov 2013 jw