re: the comment above on cutting these saws into scrapers - the plates usually used with hard tooth saws are not fully hardened, and won't make good scrapers. They can be used, but the edge life will probably be poor.
the reason the saws are underhardened is simple - it keeps newbies and hardware store buyers from breaking them easily and probably cuts the blanking and grinding costs. The teeth are hardened separately on the surface.
David, my own experience does not agree with that. Hard-point saws in general may not be quite as hard as some old "conventional" saws were, but they are certainly not tempered significantly softer than the average saw made in the first half of last century. You cannot have them much different, imo, because they would be too easily kinked (particularly by the type of user they are mainly aimed at!).
I've re-purposed many a discarded hard point after cutting off the hardened section (which only extends a mm at most below the gullets) & cutting in new teeth. The blades I've used were mostly Irwin, but I've used other brands as well, and as far as I can tell from the way they file & wear, all but one has been quite satisfactory (& that was due to excesive thickness of the plate). I've had some in use for years & mostly long forgotten which are recycled hardpoints & which are made from "proper" saw plate!
A few years ago, I bought the cheapest hardpoint "backsaw" I could find for a little demonstration. I say "backsaw" because the back was a flimsy bit of about 22 gauge metal that wouldn't noticeably stiffen your average jellyfish. My plan was to show that practise is more important than the saw & anyone should be able to saw perfectly acceptable dovetails with any saw if they applied themselves to the task (channeling Jacob here?
).
Well, I got my come-uppance there - the saw I bought (~$15), which had modified Japanese style teeth would barely cut butter, and worse, it absolutely refused to hew to the line no matter how I fought it! I had a go at the teeth with a diamond file & improved it slightly, but the jagged cut it left didn't do much for the fit "off saw":
So I made it into a "real" saw, with a proper spine instead of the useless bit of tinplate it came with:
It now cust cleanly, twice as fast, and
straight. I managed a set of D/Ts that are a bit more acceptable:
So I did end up with a decent saw, and a better idea of just how bad things have become in the saw world!
You
can do good work with a modern hardpoint (but choose a reliable brand), however, there is a huge difference between even the better ones & a good old well-sharpened backsaw in all sorts of ways. As pointed out by D.W., hardpont hand saws are like carbide-tipped circular saws - you tend to spend a lot of time sawing with an increasingly dull saw before you realise the darned thing needs sharpening or replacement!
Cheers,
