by Lowell Freeborn

The side grinding of carbide saws is the most critical grinding operation as it relates to the saw's performance.  The angles ground in the side are not as important as the uniformity of the grinding job.  The most common angles on the sides are 2° dish and 3° back for general purpose use on nearly all wood-cutting saws, 2 ° dish and 1 ° back on metal and plastic-cutting saws, and no dish and 4° back for smooth cutting rip saw applications.  Most carbide saw grinders do not pay enough attention and are not aware that this operation must be done properly.  Following is a sequence grinding operation that may help explain the major problems. Top Grinding and Face Grinding also play an important role on the Cutting ability of the saw blade.  See our Face Grinding Article and our Top Grinding article, or refer to our Saw Blade Sharpening Section for more related articles. 

The condition described in the preceeding drawing is what causes most of the saw grinding problems.  Without the point extending the farthest out on the sides, the saw has to cut without a point on the sides.  This causes it to cut rough and lead off and require more power to operate.  It can also cause burning and make the saw wobble.  It cannot be stressed enough to guard against this condition.  Machines that are weak and tired will exaggerate this problem and are very hard to live with if you need any production off of them. 

The next thing to watch is the plate springing away from the wheel.  This is caused when the plate support is too far away from the tip.  It will affect thin saws far more than heavy ones.  On very thin plates it is sometimes necessary to provide support directly behind the carbide tip to prevent it from pushing away from the wheel. 

Diamond wheels are also culprits that cause bad side grinding.  The wheels should be soft enough to cut freely and should be not less than 75 concentration.  The diamond section should be no more than 1/16" wide so that it does not exert as much pressure as a wider section would. 

Reducing the amount of stock removal and allowing the wheel to cut clean and spark out will also help. 

A simple inspection can be accomplished by holding a rule on the side of the tip and looking toward a bright light.  See if the rule will rock on the tooth or if you can see light at both ends of the tooth under the rule. 

The sides must be ground accurately and the correct angle ground so the saw can perform satisfactorily.  If you are not sure of the angles on the side of a tooth, you can find them by a simple method of using a black felt ink pen and very lightly touching the wheel to the tip. Then adjust angles carefully until you wipe off the whole side of the inked tooth. 

Saws that have been in service and exposed to abrasion and wear should be examined on the sides carefully and if wear is present it is frequently necessary to lightly dress the sides to bring them up to a sharp corner and restore their original cutting ability. 

It should be noted here that if a saw is returned to your shop dull, it should be sharpened well enough to go back into service and give the same cut quality and service life as it did when it was new.  Anything less than this is a poor sharpening job.  Sometimes as saws are returned for sharpening frequently and in very dull condition, a good thorough sharpening job each time will shorten their life expectancy because of the necessity of removing carbide all over each time they are serviced.  Remember, however, that it is better to have to apologize for a new saw wearing out too soon than to apologize for one that does not cut properly and does not go back on the job in first class condition.

Keep your eyes on the sides.