Thank you all for your advice and replies.
Raymond wrote:You might try using rivets. Just drill the holes.*snip*
I toyed with the idea of rivets however, "just" drilling holes in hacksaw blades, in my (limited) experience is not an easy thing to do, these things are tough!
I was hesitant to use "superglue" because it will perish over time, and if I'm going to spend time making things, I'd like them to last - and i mean LAST.. this is why buying a spot welder is still in the back of my mind.
So I used "Araldite" - my Dad used to swear by this stuff and I've used it hundreds of times before. Its an epoxy resin that you mix together.
In the hardware shop, chatting to the guy, I felt compelled to buy a new bench grinder - my old one must be 30+ years old. Shows they made stuff to last back then because it's still solid. The new one does the job faster, has good edges, two wheels and a handy lamp on the top.
I hastily roughed out a pick on my new grinder just to find if the glue worked. I had to leave it under some wood overnight to cure, which was difficult given my enthusiasm.
The problem I had was the glue squodging out from the sides under pressure. Fortunatley there wans't enough there to make it difficult to pry off.
After carefully grinding and sanding the glue off, you can hardly see the the three different blades there, and I got my shiny finish.
Knowing this will work now, I'll spend some time making some better machined tools and experiment a bit.
Thanks all for your time - I'll be back soon (gone to get grindin')!