Band sawing has become one of the most popular production processes in manufacturing and fabrication today. When done properly, it can be a very fast, accurate, efficient, and cost effective way of metal separation. Helping your customers get the most out of their band sawing processes is an excellent way to bolster customer loyalty and increase repeat business. However, this aspect of selling industrial band saw blades often causes problems for distributors.

At the M. K. Morse Technical and Training Center, we spend a lot of time every day helping distributors eliminate future customer service problems by selecting the right blade in the beginning. The problems we most often see relate to selecting the right blade type and tooth size for a particular application. As we have seen time and again, paying attention to these concerns pays off in terms of customer loyalty for distributors.

From our perspective, few things damage customer relations faster than having a good blade doing the wrong job. There are several things that must be considered before choosing what blade to recommend for your customer's metal cutting band saw applications.

Band saw blade manufacturers have developed a wide variety of metal cutting blades. By far, the most popular and versatile metal cutting band saw blades are bi-metal blades. Bi-metal blades are just what the name implies — there are two types of steel used to make them. The tooth points of bi-metal blades are made of high speed steel. The body of the blade, generally the area between the tooth gullets and the back edge of the blade, is made with a tough, fatigue-resistant type of steel that can withstand the tension and bend stresses applied by the band saw machines.

Different types of high speed steel are used on the tooth points. These different tooth edges have different cutting properties that allow them to perform better in certain cutting applications. New and emerging metallurgical technology has produced some very exotic and high performance edge (tooth point) materials that in some cases can approach carbide properties and performance.

One of the most important considerations when selecting a band saw blade is tooth size. The tooth size must be compatible with the size and shape of the material to be cut. The rule of thumb for tooth size is that 6 to 12 teeth should be engaged in the work for unhardened material. Having the proper number of teeth engaged in the work allows the tooth points to penetrate the material correctly to produce the most efficient chip load on the teeth. If the material is hardened, the number of teeth in the work should be doubled – 12 to 24. Blade manufacturers' tooth selection guides are generally based on this thumb rule.

The most common mistake made by users of band saw blades is using a tooth size that is too small for the cross section being cut. A tooth size that is too large for the cross section can be made to work by adjusting the in-feed rate of the blade so as not to produce an excessive chip load. A tooth that is too small for the section cannot be made to work properly. As the teeth enter the material, the gullets (the rounded portion of the tooth edge into which the chips flow) begin to fill with chips being formed by the tooth points. If the tooth is too small, the gullets become totally filled with chips before the blade exits the cut. With the gullets completely full, the penetration of the tooth points is severely restricted and the points can no longer create the proper size chip. The result is either premature dulling, tooth strippage, or crooked cuts.

Bi-metal blade type is also an important consideration when selecting a blade. The type of blade to use largely depends once again on the size and type of material to be cut. Matrix II Bi-metal blades are tough and shock resistant. The tooth points are less likely to chip in rough cutting applications. Rough or abusive cutting situations can be caused by the shape of the part to be cut, the conditions of the saw itself, or the nature of the way the saw is used. Structural shapes like angle iron, channel iron, square tubing and round tubing are interrupted cuts. This means that during the cut, the blade enters and exits the cut more than once during the cut. These types of shapes typically cause more vibration when being cut and apply more shock to the tooth points particularly if the wall thickness is ¼" or less.

Smaller, less expensive manual band saw machines typically are not made with the massive frames and stiffness seen in larger, automatic production cutting machines. This also produces more shock and vibration. This type of machine is often used in smaller fabricating businesses and MRO (maintenance and repair organization) type facilities. In these situations, usually there are multiple saw operators who cut a wide variety of shapes, sizes, and material, often not taking the time to change speeds and feeds on the machine. These types of blade users want a "general purpose" blade for cutting everything, but one single blade specification cannot efficiently cut all the different shapes and sizes.

Production facilities, for example, gear manufacturers, contract cutting houses, forging facilities, and steel warehouses, just to mention a few, usually require more specific, higher technology bi-metal blades. In these types of businesses, often there are many saws that are dedicate to cutting a more narrow range of shapes and sizes. They typically cut longer runs of the same material over and over. The saws are usually larger, automatic-type machines with better capabilities than the smaller manual-type machines. These types of blade users often keep extensive blade performance and operating records. Blade speed and feed parameters are changed to suit the material being cut, and the saw operators are usually better trained and experienced. M42 Bi-metal blades and new technology blades with their higher hardness and increased wear resistance are the best choices for these users. Although these high performance blades are more expensive than Matrix II blades, their enhanced performance and extended life will almost certainly reduce cost per cut.

Remember, information is the key to recommending the best possible blades to the end user. Get as much information as possible about the shape, size, and condition of the material to be cut, the type of machine on which the blade will be used, and the type of cutting that will be done (production vs non production). Also remember, you are not alone out there. Use the technical assistance of blade manufacturers, and have as much information as possible ready for the technicians.

Customer loyalty and repeat business is more important than ever in today's tougher economy. Recommending the correct cutting tool and helping to improve your customer's cutting efficiency can be extremely valuable in building customer loyalty, trust, and repeat business.

For blade application assistance, call M.K. Morse's Technical Support Hotline at 1-800-733-3377 or visit www.mkmorse.com.