Hardened Saw Teeth vs. Resharpenable Saw Teeth
Top - Modern Saw with hardened teeth and plastic handle
Middle - Vintage Saw, properly made with comfortable handle and resharpenable teeth
Bottom - Modern Saw, crudely made but with resharpenable teeth.
As a woodworker when you look to invest your money you have two main options for handsaws. A saw with hardened teeth or a resharpanable saw. It's easy to think that "hardened" would be better, and in some situations they are. Let's weigh up the options and at the end I'll share my experience, what I use and why.
Hardened teeth
These are also know as hardpoint, impulse hardened or disposable saws! The teeth of these saws undergo a hardening process. These hardened teeth stay sharper for longer. When they eventually become blunt, the saw has to be recycled and replaced.
Typically the teeth that are hardened will often appear black or blue colour due to the heat. The concept became popular during the mid and late 20th century. This type of saw dominates all hand saws sold.
Typical examples of saws with hardened teeth will be found at Builders Merchants, cost less than £10 and have a plastic handle. They can be bought in ranges from coarse to fine and from a larger handsaws down to a small tenon saws. These are mainly used by contractors and people working with abrasive materials like chipboard and MDF. They work well with solid wood, especially cross cutting but are not very effective ripping solid wood.
Nearly all commercially available Japanese style saws feature hardened teeth. These saws are available from tool dealers and you won't typically find them in a local hardware store. They are available in a wide range to suit various applications, including ripping. Although the very large rip saws aren't widely available. Dovetailing, cutting tenons and general woodworking can be done effectively with these saws. When the blade becomes blunt the handle is kept and a new blade fitted.
Because the teeth on these saws have been hardened, you can't sharpen them with a normal saw file. Diamond files can be used to sharpen them but buying diamond files may become expensive. So much so that it may cheaper and more effective to buy a new saw.
If you do attempt to sharpen these saws (I don't recommend it) you will be removing the hardened part and will be soon left with a blade of soft metal that will blunt quickly.
Sharpening a saw is a worthwhile skill to learn. Here’s my approach to sharpening a crosscut saw
Resharpenable teeth
These are teeth which have been cut into a saw plate. The saw plate is made hard enough that the teeth hold an edge for an acceptable amount of time but soft enough that a normal saw file will allow you to sharpen them. On cheap resharpenable saws you might find and etching or something on the packaging that indicates it can be filed. Many saws in this category are comparatively expensive as they use traditional methods of manufacture including properly shaped wooden handles, brass backs and on handsaws, a taper grind.
Traditionally, almost all saws had teeth which could be resharpened. Because of this there are many old quality saws that can be restored and used. Learning how to sharpen a saw can take a bit of time but with an old saw and some practice it can be learned. It's far from being a lost art with plenty of good instruction available.
My Choice
I use both hardened and resharpanble teeth. My plastic handles saws fit well in my site box where they may encounter poor weather, a rougue nail or abrasive material. With theses rsks I would have to dedicate too much time to sharpening. If I'm at the bench and making joinery I like resharpanble saws. Here I'm working with clean timber and the edges last well. I also like to restore old saws. It's perhaps pathetic but I find it the willingness of our society to dispose of the history of of trades sadening. If I can leave a few good saws for others to enjoy that it a good thing. Do I feel I'm being wasteful by using "disposable" saws. Not at all! They can be recycled and answer a question that is posed to me. Do I want to trash my nice saws on work that puts them at risk? No thank you! As to Japanese style saws vs our Western style saws, that's for another day.