Cutting Metal: "What Could Possibly Go Wrong?!"
What could possibly go wrong with cutting tools? First Kevin talks about his DeWalt 872 chopsaw. It is a metal cutting saw with metal teeth instead of an abrasive blade. When the toothed blade wears out or gets dull, it can be resharpened. When abrasive blades wear out, you just throw them away. Kevin shows you the difference between an old, dull blade and a resharpened blade. That will help you see when you need to replace your blade.
First, though, he puts on his safety equipment. He uses and recommends hearing protection and eye protection. That's especially true with this machine, because it does spit, throwing metal chips, and it's loud. Kevin cuts a 1" solid metal rod. Sparks fly!
Then he changes to a refurbished blade with the same tooth count as the first blade he used. He reuses blades because new ones can cost as much as $240 each, so it's worth it to sharpen them. He cuts another slice off the 1" solid steel rod. This time, there are hardly any sparks.
He adds that you don't need to push down on the blade to cut. Just the weight of your hand should be enough. If you are pushing, you can damage the cutting blade. Kevin shows the two slices and points out how the new blade cut more cleanly and smoothly.
Why does it matter if your blade is sharp instead of trying to get the last cut out of every blade? You get an ugly cut intead of a nice smooth one. Using a dull blade puts more heat into your material, which makes it expand more, and there's more of a chance of your metal coming out of the vise because the blade is dragging as it's going through and you're pushing.
You also might pop off some teeth, and replacing a tooth on these blades can cost as much as $65 each. That's in addition to the cost of sharpening the blade.
It's a good reason to go slow, use hand pressure only, and use a sharp blade. That means there's less chance you'll rip off teeth or bend the blade - if you bend it, it's done. The blades will last a long time if used properly.
Also be sure to use clamps correctly. Put your work in, then clamp it without over tightening - just get it snug. If you try to crush it, you can put so much pressure on the clamp backstop that you can bend the table. That can lead to your metal slipping out.
Next Kevin shows a plate shear, which is great for cutting 1/4" and smaller pieces of metal. It also can cut metal plate of a certain width. It's limited because it has a throat. It's good at cutting straight lines, but if you want to cut curved lines or want a throatless shear, one choice is a Beverly shear, which also cuts curves. Don't try to cut heavy stock with it, though, or you'll ruin the blade, which is more like a pair of scissors. If you damage them, you have to throw them away.
It's always important to match your material to the tool you are using. Don't try to overpower one or the other, run something too thick or too thin.
There are a lot of other cutting tools, too. Jigsaws, hacksaws, grinders with cutting blades, plasma cutters, oxygen acetylene torches - lots of ways to cut metal. Always try to use the right tool for the right job. It's quicker, it gets better results, and it's safer.
Kevin is ready to go back to work, but before he goes, he acknowledges he is done ....
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