Buy a Cross Cut Carcass Back Saw
I have found that a lot of small cross cut operations (like with mortise & tenon joints and dovetail joints) can be accomplished with a dovetail saw, because even though it has rip teeth, the teeth are so small that they can make an acceptable cut. This is good news for woodworkers who can only afford to buy one back saw. But if you want a cleaner cut, and the ability to make longer cuts (like a shelf dado) then a longer crosscut saw, like a “Carcass” saw, is what you should buy.
Traditionally, the frames of furniture casework were called a “carcass”, so the common crosscut back saw used to cut dado joints and mortise & tenon joints was called a “carcass saw”. Typically a Carcass back saw is longer than a dovetail saw, so that it can be used to cut longer dado joints for shelves.
Vintage carcass saws for sale are rarely listed as “carcass”. A lot of uninformed sellers list them as “dovetail saws” or “tenon saws”. But at around 11″ to 14″ long, with a saw plate less tall than a tenon saw, they’re obviously not dovetail saws or tenon saws. So keep that in mind when searching around for one. Carcass back saws will have around 11-14 ppi. A tenon saw can easily be converted into a carcass saw by sharpening the teeth for cross cutting.
Read the above section on buying a dovetail saw to see why I chose to invest in new Lie-Nielsen back saws. So years ago, after a lot of research, I decided to also purchase their 14 ppi cross cut back saw (see it here) for cutting joinery across the wood grain (e.g. cutting tenon cheeks).
This is the carcass saw of choice among students in my woodworking school, because of the thin saw plate and ease of cutting. These carcass saws come ready to use from Lie-Nielsen, and won’t need to be sharpened for a long time.
I also own several Disston back saws that I have changed to crosscut back saws, like this Disston No. 4 steel back saw:
It really is a great back saw, but required a bit of refurbish work and sharpening to get it cutting nicely. But I like refurbishing hand tools and sharpening hand saws, so it was not a chore for me.
If you decide that you’d prefer to buy a vintage/antique back saw, make sure to inspect the blade for kinks. Hold it up to your eyes, and sight down the tooth line to make sure the saw plate is straight.
If you’ve inherited (or accidently purchased) a hand saw with a kinked saw plate, as a last resort you can smack the back of the steel/brass back of the saw on a piece of wood and it may straighten out, but not always (and it can make it worse), so it’s best to buy back saws with straight saw plates. Also check the handles for broken pieces. A broken saw horn is very common, but certainly not a problem if you’re looking for a low priced back saw.