SPYRAL BLADE BANDSAW APPLICATIONS
Spyral bandsaw blades are manufactured to order by Bestway Products Company. The blade material is run to a specific length leaving the two ends with out the spiral tooth. This enables the welding of the ends to take place away from the tooth to provide a stronger weld.
Blades are used on both custom built saws and standard bandsaws that have been adapted. They can not be run on a conventional bandsaw with out modifications. Because they are not flat, Spyral saw blades behave differently than conventional blades. Typically the user must spend some effort developing a process in order to obtain satisfactory results. For these reasons Spyral bandsaw blades are not marketed to the general public and are primarily used by commercial and industrial companies.
Spyral blades are made of tempered carbon steel and have a hardness of approximately Rockwell C 53. They are suitable for cutting light alloys and light gage metals as well as softer materials such as plastics, elastomers, wood, insulation, bone etc. They are not suitable for cutting hardened alloy steel, glass, or rocks.
The size (diameter) of the wheels will determine the fatigue life of the blade when used with softer materials (i.e. when the blade does not wear out first). The smaller the wheel diameter the shorter the blade life will be. In general, we recommend wheels that are 24” in diameter or greater. Smaller wheels can and are used in some applications. Wheel diameters under 16” are not recommended. The quality of the saw also effects blade life. Wheels must be balanced, parallel and aligned. Positive mechanical, hydraulic, or pneumatic tensioning is recommended rather than spring tensioning.
If the wheels are crowned a small groove is needed in the tire of the wheel to receive the blade. This groove need only be as wide as the blade and half as deep. It will not interfere with the use of a flat blade. If the wheel is flat and has good tracking control or is grooved this is not necessary.
Round blades require the use of roller guides. Bestway sells two styles of guide rollers. The most used is a sealed bearing that fits a 10mm shaft with a urethane grooved tire bonded to the OD (PN BGSBUT). This guide roller is normally used with the .040 and .050 inch diameter blades. The second guide roller is a bearing with an integral steel “U” shaped groove on the OD (PN BGGBR). This is typically used with the .074” diameter blade for friction cutting hard thin gage metals such as titanium and stainless steel.
Guide rollers are typically mounted in pairs on a bar which pivots on a shaft. Either one or two pairs (at right angle to each other) are used depending on the application. Often guides are only needed on top, above the table. For thick materials or greater precision guides are also placed under the table. Photographs of typical installations are available. Because of the wide variety of band saw configurations Bestway does not provide mounting hardware and only one configuration of a pivot bar/shaft with two guide wheels (PN BGSMU with urethane tires or BGFCU with steel “tire”).
Urethane guides should maintain constant contact with the blade to reduce wear with out causing the blade to bend around the roller. Replacement urethane tires are available.
Feeds Speeds, and Tension
Blade speeds are typically between 3, 000 and 5,000 SFM. Variable speed control is very desirable to “tune” the blade away from harmonic frequencies and control blade vibration. With out speed control only tension is available to reduce vibration in the blade. This can be more pronounced in a round blade than in a flat blade. The smaller diameter blades are sensitive to tension and excess tension will reduce blade life. In general it is best to use the lowest tension that will accomplish the cutting task. Blade tension is difficult to specify but on the .040 and .050 inch blades should approximate that used with a 1/8 – 1/4” flat blade.
A new user will usually need to put some effort into process development to establish the best blade diameter, speed, feed and tension for both cutting and blade life. Spyral blades are unique and do not behave the same as flat blades. We usually recommend that new users purchase at least 3 blades to start. The first is to experiment with and usually break. The second is to run and the third is a spare. Because blades are made to order it is best to allow at least a week lead time when ordering.
Our goal is to provide assistance in helping you have a successful adoption of Spyral saw blades to meet your needs. We can often assist by cutting sample materials here to help establish the best parameters before you undertake converting or building a machine. However, experience has shown that each application usually has its own unique aspects. Our purpose is to ensure your success, not just to sell blades.
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