Air hammers are a major investment. However, they increase speed to about 6 to 7,000 blows/minute. Still, you stay in touch with the stone meaning that you do not lose control; stay “spiritually” connected. Too often with a saw or grinder, we lose sight of our design – off goes a nose or paw. (Been there!) The air hammer retains that feeling of hand chisels where we still feel the stone and stay “in control.”
Air hammers are classified by two variables: piston diameter and travel distance. The larger the piston the more “punch”. So, the small air hammers might have a 5/16” or ½” diameter piston whereas the larger ones might have a ¾” or 1” diameter piston. This has no connection to the size of the chisel. They almost always have ¼” or ½” shanks to fit in the air hammers.
The travel distance or “stroke” refers to how far the piston goes up and down. A far distance is called a long stroke and a shorter one is a short stroke. Again, the longer the stroke the more power. Long-stroke air hammers might be required for hard stone and larger projects. It does take a toll on your wrist but gets the job done. We prefer these air hammers (Cuturi and Trow and Holden) as they have very few parts and are therefore very reliable. The major difference between these two brands is that the Trow and Holden has long and short-stroke hammers while the Cuturis split the difference and have only medium-stroke air hammers.
One last note: air hammers are controlled by a valve on a short, attached hose. This is called a “whip.” Never run an air hammer full throttle or without the valve. That is too much air and usually, the valve is opened no more than halfway.