Will a table saw cut through nails? Unfortunately I know the answer is yes. But I don’t recommend it, generally speaking, for a couple of reasons.
The visible sparks that happen when you try to cut through nails with a table saw suggest what you’re doing isn’t a great idea. But you’ll also dull your blade, which creates a safety hazard long after the sparks stop flying.
Using a table saw to cut through nails dulls your blade
The first reason I don’t recommend using a table saw to cut through nails is because it will dull your blade. People cut through nails with reciprocating saws all the time, but reciprocating saw blades cost about 20 percent what table saw blades cost. And it’s easier to design a reciprocating saw blade that can cut both wood and metal adequately, due to the speeds involved.
I wasn’t very happy when I started to rip a 2×4 with a blade that was about eight cuts into its lifespan, then discovered it had nails in it. It did cut through the nail–I could see it after I stopped the cut. But I could also see the wear on my blade.
The blade still works, and I’m sure that one nail won’t reduce the blade’s usable life all that much. But if I made a habit of cutting through nails, I’d wear that blade out pretty fast.
Wood is cheaper than steel, so when I salvage wood, if I can’t get the nails out of it, I don’t use it on my table saw. It’s not worth wearing out my blade to save a couple of bucks. A dull blade is less safe and doesn’t cut as nicely. I’d rather buy new lumber and keep my blade sharp.
Cutting through nails creates a shower of sparks
You may wonder why I knew I was cutting through a nail. The telltale sign was the shower of sparks I saw. So I immediately shut the saw off to make the shower of sparks end. I also pulled the board back, which may have put me at the risk of kickback, but since I wasn’t standing directly behind the board, I was willing to risk that.
Sparks with sawdust and dry wood create a safety hazard. I can tell you from experience in my fire pit that it’s not easy to light a 2×4 on fire. A few sparks won’t light the 2×4 on fire, but they may light sawdust on fire. With one nail and stopping it right away, I don’t think I put myself in any grave danger. Cutting several boards full of nails with the table saw might.
The blade is probably a greater risk than the potential for fire. But the shower of sparks is probably a little bit more effective at motivating you to stop.
What to do instead
If you know where the nails are in your boards, cut those portions off and use the shorter boards in your table saw. This is why I’m not too keen on using pallet wood in my table saw. Pallet wood is more likely to have broken-off nails I can’t see. It’s fine to use for other things, but not for table saw projects.
If you must saw wood with nails in it, use a jigsaw with a metal cutting blade instead. It will be slow going, but you won’t mess up a $35 circular saw blade.
My favorite trick for saving money on lumber is buying cull lumber. I’ve bought enough lumber for $6 to build desks before, and without putting unnecessary wear on my saw blades.