303 303 Find detailed specifications, pricing, and availability at WhiteCap.com Stay sharp with blades in great condition. When blade problems occur they are often caused by the wrong blade being used for the wrong job, the blade being used incorrectly or if there is an equipment fault. Here are some examples of blade problems. Loss of tension. Some possible causes: the blade is too hard in relation to the material being cut or the blade is used at the wrong speed of rotation. Recommendation: change the blade. Cracked segment. Possible causes: the blade is too hard for the material being cut or the cutting speed is too fast. Recommendation: change the blade. Cracked center plate. Some possible causes: cutting pressure is too high or the blade has overheated due to inadequate water supply. Recommendation: change the blade. Eccentricity. Some possible causes: the bond is too hard for the material being cut or the spindle bearings are worn. Recommendation: change the blade. Glazed. Possible cause: the blade hasn’t had adequate pressure when placed against the material being cut. Recommendation: change the blade. Regain sharpness. A diamond blade can become dull when the wrong feeding pressure is used or when cutting certain materials such as heavily reinforced concrete. To sharpen the blade, cut in a soft material such as sandstone or a brick. Aggregate Map Type of Sand Sand is part of the aggregate mix and determines the abrasiveness of concrete. ‘‘Small aggregate’’ is usually sand. Sand can either be sharp (abrasive) or round (non- abrasive). To determine the sharpness of sand, you need to know where the sand is from. Crushed sand and bank sand are usually sharp; river sand is usually round. Green concrete is more abrasive than cured concrete because when concrete is not fully cured, sand can easily be scraped off the surface being cut. More loose sand means more abrasiveness. Steel Rebar Reinforcing Heavy steel reinforcing tends to make a blade cut slower. Less reinforcing tends to make a blade cut faster. Light to heavy rebar is a very subjective term. Examples include: Light Wire mesh, single mat Medium #4 rebar, every 12" on center each way (OCEW), single mat Wire mesh, multi-mat Heavy #5 rebar, 12" OCEW, single mat #4 rebar, 12" OCEW, double mat Heavy rebar can also result from different grades of steel. Typical rebar is grade 40 steel. Grade 60 steel would make the example of #4 medium rebar, above, into a heavy rebar. Rebar gauges are in eighths of an inch - #4 rebar is 1/2" diameter, #5 is 5/8". Where rebar specifications do not exist on a road, pull a core sample before buying a blade. Green or Cured Concrete The drying or cured time of concrete greatly affects how the material will interact with a diamond blade. Green concrete is freshly poured concrete that has set up but is not yet fully cured. It is softer and more abrasive than cured concrete. You need a harder, bonded blade with undercut protectors to cut green concrete. You need a softer bonded blade to cut the same con- crete in a cured state. The definition of green concrete can vary widely. Weather, temperature, moisture in the aggregate, time of year and the amount of water in the mix all influence curing time. Also, a lot of concrete now has additives which can either shorten or extend curing time. Consult your mix design to find the relative curing time for your job. As soon as wet concrete sets up and does not spall or ravel, green cutting can begin. Aggregate Classification Soft Medium Soft Medium Medium Hard Hard How to Choose the Right Diamond Blade targetblue.com Mohs' Range Description Aggregates 8-9 Critically Hard Flint, Chert, Trap Rock, Basalt 6-7 Hard Some River Rock Some Granites, Basalt, Quartz, Trap Rock 4-5 Medium Hard Some Granites, Some River Rock 3-4 Medium Dense Limestone, Sandstone Dolomite, Marble 2-3 Medium Soft Soft Limestone KICKBACKS AND PINCHING HORIZONTAL, VERTICAL, AND PIPE CUTTING A kickback is the sudden upward motion of the power cutter that can occur if you stall the blade in the wrong way. Another hazardous situation is when the blade is being pinched. 1. Never use the blade’s upper quadrant, the kickback zone, for cutting. 2. If you are using the blades kickback zone to make a cut, you might be exposed to a climbing kickback. 3. When you are cutting a block or a pipe on the ground, make sure that the material is properly supported and can neither move nor roll during cutting. Also make sure to place the cut right to avoid the blade being pinched. 4. If the cut closes and the blade is pinched, this could cause an aggressive reaction force that makes you lose control of the machine. 5. Be careful when you insert the blade in an existing cut. If you don’t insert the blade straight, it may become pinched and cause a kickback. Horizontal Cutting 1. To start with, mark where you should cut. 2. To cut horizontally, start by making a guide cut approximately 2 cm deep. Cut from left to right to have a clear view of the cutting line. 3. Then go deeper, using step cutting, approximately 5 cm deep at a time. Vertical Cutting 1. To cut vertically, start by making a guide cut approximately 2 cm deep. Cut from the bottom to the top to have a clear view of the cutting line. 2. Then go deeper, using step cutting, approximately 5 cm deep at a time. Cut from the top to the bottom. Always maintain full speed for best cutting performance. Pipe Cutting Always cut pipes in the following three steps: 1. To cut a pipe, start by cutting the top. 2. Then cut one side of the pipe from the top to the bottom. 3. Move to the other side, and cut the remaining part of the pipe from the top to the bottom. SELECTING THE RIGHT DIAMOND BLADE FOR YOUR AREA MOH’S RANGE DESCRIPTION AGGREGATES 8-9 Critically Hard Flint, chert, trap rock, basalt 6-7 Hard Some river rock, some granites, basalt, quartz, trap rock 4-5 Medium Hard Some granites, some river rock 3-4 Medium Dense limestone, sandstone, dolomite, marble 2-3 Medium Soft Soft limestone Diamond Blade Performance PROPER TECHNIQUE SUPPORTS SAFE CUTTING DIAMOND BLADE TROUBLE SHOOTING 397 VISIT US ONLINE
