Posting for a member friend that is trying to figure out what model/year(s) this trap is?

No one wants to comment so I will ask a more specific question. I've noticed three chain types used by B&L: 1-Niagara Pattern (similiar to twin loop), 2-Lock link like on this trap, 3-regular twin loop like modern day. Does anyone know the general year dates that these types of chains were used and if any other types were used by Blake & Lamb? Any other details such as chain type on various size or types of trap would be great also.

I have Waterbury's with different chain/swivel/ring set ups, actually have bought them because of that, lot of variations, but, with no real reason just always assumed the chain in your picture was later Waterbury since that was standard in Hawkins. Since those were offered with or without chain when new it's hard to say any chain isn't correct. I'd be interested to know if there is anything on record about chains too.

It is a nice looking trap,,

1880 -1890"s my guess

I thought it was more a 1900s era trap with the marking and chain. They were made so similar for about a 25 year period that it is tough to narrow the time and because of the wide time range and number built, they are common enough that they do not bring much value. In fact, other than the 0 pictured, most other sizes of Waterburys remain just user traps unless they are near new.

up to around 1905 or so.not an early one or it would have 1859 or 1873 date.Bruce

That style of chain used until 1969.Still a nice trap