This is a plural form, grammmar-wise ie:
* los instead of el
* ~os on the end [los conteros (pl) la contera (sing)]
So it first indicated his occupation description applies to a set, like a labouring gang or group. Much like a 'digger', is applied in NZ?
Dictionary:Found no singular in male form : contero
But contera (female form) comes up (as you've found) as meaning : ferrule
Ferrule:
http://en.wikipedia.org/wiki/Ferrule" a name for types of objects, generally used for fastening, joining, sealing or reinforcement. ...often narrow circular rings made from metal ...Ferrules are also often referred to as eyelets or grommets within the manufacturing industry....Most ferrules consist of a circular clamp used to hold together and attach fibers, wires, or posts, generally by crimping, swaging, or otherwise deforming the ferrule to permanently tighten it onto the parts that it holds...."Googling brings up restaurants named Los Conteros, in Villaricos, Spain
Then finding reference to the archaeological site of Villaricos in Cuevas de Almanzora Almería ……..also known as the city of Baria and Conteros . Cuevas de Almanzora formerly named Cuevas de Vera) is a municipality of Almería province, in the autonomous community of Andalusia, Spain.
One can gooogle translate parts of this page, gives an overview and reference to the metal mining the area was know for:
http://www.cuevasdelalmanzora.es/Then found this:
http://www.rootschat.com/links/01f1d/Diccionario español e ingles, 1786
CONT'ERA
The small iron or silver cone they use to put at the end of a scabbard.
Use: Echár la contéra, meaning: to finish, to make an end.
So perhaps:
A gang-worker, a collective name for a group of labourers whose collective job it is to finish, put the ends on something in the metal mining industry or just working with metal parts in associated construction/engineering fields.
(My brain minds/eye is making it akin to riveter, but not quite so 'skilled' or specific a job as that)I can only suggest that as the collective 'Los Caballeros' can be used for different inferences (serious, humourous, specific, loosely) to horsemen, cavaliers, knights, gentleman, muskateers (as in Los tres caballeros) - then so can Los Conteros in the metal mining industries? I do think he would have been part of a gang of workers, like navvies.
Maybe that's it: a navvy at the metal mines?
Cheers
AMBLY