Frequently Asked Questions

Below are some of the most frequently asked questions about our products:

  • I have a 4.5″ mini-grinder with a 5/8″-11 spindle. Can I use a 7″ or 9″ grinding wheel on it if I remove the wheel guard?
    Never use a wheel that is larger than the machine designed for. The guard is there to protect the operator from sparks and fragments caused by the grinding process. Also, a smaller grinder turns too fast for the larger diameter wheels.
  • I have a 14″ electric chop saw that I use in my shop. Can I use the same blades for my 14″ gas powered high speed saw?
    Many 14″ electric chop saws that use 1/8″ or 7/64″ blades don’t have enough power to run the heavier duty 1/8″-5/32″ blades that are normally required for use on high speed gas saws. They may bog down the electric saw and cause harm to the motor.
  • I just started using flap discs. How do I know when they are worn out and need to be replaced?
    Flap discs are designed to provide a longer life than regular resin fiber sanding discs. As the discs wear down, a slight increase in pressure on the work surface will create new cutting surfaces. Flap discs can be used all the way down to the fiber backing in most cases.
  • I need to use a high speed gas saw with a masonry blade to cut up some concrete. Should I be concerned if I hit some steel re-bar while cutting?
    Mercer’s high speed masonry blades will cut through the steel without problems. Just make sure to always wear a pair of Mercer’s safety glasses to prevent injury from flying sparks.
  • Can I use my metal cutting grinding wheels and abrasive circular saw blades on stone or concrete?
    We do not recommend it. Metal cutting blades and wheels use aluminum oxide as their primary grain. Silicon carbide is the proper grain for optimum cutting on masonry and stone materials
  • I set my right angle grinder on the bench in the shop and the cord got snagged accidently and the grinder fell on the floor. The wheel on the grinder looked fine and the guard was removed. Is it ok to use this wheel?
    We would advise against using the wheel in such a situation, since the guard was removed and it also fell on the floor. Dropping grinders can create small cracks in the wheels. Many times these cracks do not readily appear to the naked eye. Even if the guard was still on the grinder, it may be unsafe to use that wheel again.
  • When I use my right angle grinder to grind metal, small chunks fly off and hit my hands and arms. Is there something wrong with the wheel?
    The guard on the grinder must be used. It will guide sparks and wheel fragments that are common in the grinding process away from the operator. Also, when grinding metal, or any materials for that matter, it is advisable to wear good work gloves with a guantlet type cuff to protect the arms and hands. Always wear eye protection. Mercer Abrasives has both high quality gloves and safety eyewear to prevent such injuries.
  • I am using a 14″ chopsaw to cut 8′ metal shapes. As I start cutting, all seems normal until I get towards the end of the cut. The blade starts to bind up and pinch the blade. What is causing this?
    When cutting long lengths of material, make sure that it is properly supported to keep the material from pulling down as you cut. The blade then cuts through the material it pinches, if it is not supported, then that could bog down the saw or worse, cause the blade to break apart.
  • I was having a muffler installed at a shop and I noticed one of the mechanics using a 12″ chop saw to cut the muffler tubing. When he was finished with the cut, he used the side of the blade to grind away the burrs from the tubing. I asked if that was safe to do and he replied that he had done it like that for years. Is it safe?
    When the side of the wheel was used as a grinder, he was grinding away at fiberglass matting by the side of the wheel where the reinforcing was, which is not a safe thing to do. If he had “done it that way for years”, he was lucky that he did not have catastrophic wheel failure. A combination belt and disc sander is the proper toll to use in cleaning up burrs. Mercer offers both 12″ and 14″ thin cutting blades which are great for burr free cutting on most thin wall muffler tubing.
  • I have noticed that my 14″ chopsaw blade has what appears to be a shiny brown residue at the bottom on the face of the blade. The blade does not seem to cut well. Is the blade ruined?
    The blade has a “glaze” or better defined, the resins have actually burned from the friction of the blade on the work surface. To remedy “glazing”, apply more pressure on the downward pull of the chopsaw to force the grains to fracture and create new sharp cutting edges. If that does not cure the problem, you may have too thick of a blade for the horsepower that your saw has. One quick cure for the “glazed” finish is to take a thin piece of scrap metal or tubing and run the blade through it a couple of time which should clean it off.
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