Here's some photo's of the 14" Jacks I have. The one with a closed handle has a 1 3/4" Hearnshaw iron and no makers mark, all I know about it is that it came from a joblot in Scotland, originally had a large blob on the heel which, together with the rather primitive initials dug into the side probably indicate it originally came from a school. I ground a camber on it and, possibly due to my lack of space (I have a 4'x2' bench and couldn't use the ends) found it a very handy size. The pronounced curve on the top of the handle means that I have never felt that the iron was too close, although there are hammer marks. (Not from me - I blame the kids!)
The other three were sold to me by the grandson of the original owner, who worked I seem to remember, in the 1930's as a furniture maker. They are all modified and were working tools. Embarrassingly I've had them for quite a while and done nothing with them. The sole of one has a pronounced camber, another quite a gentle camber - any ideas on why that was?
Cheerio,
Carl