On what subject(s) are you an authority?
I’m pretty sure that people who claim to be authorities on anything only know a portion of what they’re talking about because every day brings new stuff to light.
If I had to choose one area, though, I would say I know a fair amount about wooden jigsaws from the very late 19th century to around the middle of the 20th century.
I have not seen every jigsaw nor have I put together every jigsaw but I have seen many of those made in Britain and a few from elsewhere. For about nine years I bought and sold them, and, each one I sold I put together before selling it so I could assure the buyer that all the pieces were there or warn that several were missing.
Now, there’s absolutely no way I would use a bandsaw and am not really good at sawing with a fret saw but I have made new jigsaw pieces with a plastic/resin material, the name of which has completely gone from my mind! The making wasn’t too difficult as long as you had all the pieces surrounding the hole left by the missing one – the difficulty was in painting the piece once it was made. I am not an authority on that – nine years isn’t nearly long enough to work out that problem – but I didn’t try to pass off a remade piece as perfect and my customers were always happy.
If you are interested in wooden jigsaw puzzles, there are two earlier posts in this blog and some photos of some of my favourites.
Below are two jigsaws I did for fun a couple of years ago. Both of them are ‘vintage’ (pre-1960, definitely but undated). The biggest one was too big to put together on the board, as you can see. It had several pieces missing which were remade by someone else. Both were very enjoyable!

