How to Use Your HSRT on Metal.
There are four main areas of metal work that a HSRT is very good at: Cutting, grinding, polishing and engraving. We will cover cutting and Grinding here and talk about polishing and engraving in JEWELRY
Cutting Metals: Nails that stick out and bolts that are too long are two of the most common problems that a metal cutting HSRT can solve. These are "mild steel" and easily cut with a fiberglass reinforced cutting disk. The fiberglass reinforced disk is a good one to practice with as metal cutting disks are fragile and break easily.
The metal -cutting disks are mounted on the machine-screw mandrel in the same manner as sanding disks. Note:, the screw must be tight on the disk to prevent slipping. If the disk begins to slip, it will cut the screw off!
Secure the metal! If the nail you wish to cut is embedded in a large piece of wood, or the bolt is fastened to a gate, you can be reasonably sure that the metal will not move as you cut it. However if you wish to cut a loose nail or bolt, it must be clamped or held firmly in place.
Use High Speed! 30,000rpm or faster will make smoother cuts.
Steady the HSRT! The metal cutting disk must move thru the metal in a steady controlled manner, and must not flex or twist in the cut. This will cause the disk to "bind" in the cut, and kick back, or shatter.
Climb Cut! This is most important when cutting sheet metal, but metal cutting disks work best cutting the opposite way to cutting wood. See photos.
Caution!:. Cutting metal will create sparks, relatively harmless little sparks if they hit your glove or clothing, BUT, if there are any flammable fumes, ( gas, paint thinner, propane, butane, etc. ) in the area, they will cause an explosion and fire. Never create sparks if there is any trace of flammable fumes. Sometimes these little sparks can ignite very dry wood. If, for example, you were cutting a pipe inside the wall of an older house, you should take precautions to prevent fire.
Tip:. Keep a spray-bottle of water nearby. This is the same type of spray-bottle that you would use to "mist" your house plants, and it makes a great little fire extinguisher. For very little fires, of course! Before making sparks, spray the wood with water and a fire will not start. Keep a "real" fire extinguisher nearby but try not to use it, as it makes an awful mess!
Climb Cut: Note that the "Rotation" of the disk makes it want to "Climb" out of the cut. Hold your HSRT steady to prevent this. Use light pressure and give the disk time to cut the metal. Photo 2 demonstrates cutting a metal bar and the two-handed secure grip on the HSRT. The metal must be secure and the HSRT cannot "wobble". If you cannot brace your hand or arm on something solid, stand close to the HSRT and brace your hand on your hip. After you practice this a bit, it becomes easy.
Note: The metal and the cut-off piece will become very HOT. Let it cool before touching.
Grinding Metal: Move the stone in the same direction as the Rotation, and move it relatively quickly. It the stone is held in one place too long it will overheat, and "burn" the metal. Also moving the stone quickly gives you better control over the final shape you are creating in the metal.