[TheForge] Old Air Tool Help ?

[lama]

I acquired a Chicago Pneumatics Planishing Hammer yesterday.
The tool plate says:
______________________________

    C.P. PLANISHING HAMMER
Type: 522              Serial: H185617
Chicago Pneumatics Tool Company
Detroit Plant                          USA
______________________________

I posted some pictures of it here: 
http://magichammer.freeservers.com/planishinghammer.htm 

Does anyone have any information about this hammer?
It almost works and with some TLC and a lot of penetrating
oil it will once again be a fine tool. Any information that I can
find will be useful. Schematics, old catalog specs, parts list,
instructions, anything at all.
Thanks 
Dave Mudge