Peter, >>Does any one know of an authoritative sources for the terminology of the different part sof the hammer in a forge?<< I don't know of any specific sources for the information that you are after, but have you tried the OED? My concise version gives "gudgeon: pivot at end of beam, axle, etc., on which bell, wheel, etc., works" The _Transactions_ of the Newcomen Society sometimes have papers on the iron industry, it might be worth having a look at the indexes - any good central library should have a run of them. I have also come across odd historical articles in the _Journal_ of the Iron and Steel Institute, but this might be harder to track down. Regards, Peter Park. Walton on Thames, Surrey, UK. %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%