High Strain Bandmills

The Filer & Stowell air strain band mill is ruggedly built for long life with traditionally known features and a few surprises. The heavy duty fabricated construction of F & S equipment is a standard in the industry. So is the no-nonsense design of this unit. Everything about this band mill says 'strength' and that means quick response to any cutting situation through our unique 'two-in-one' straining system. The air strain portion of this band mill works with standard shop air from 70-120 PSI which is directed to our built-in accumulator and then to ultra-sensitive pressure regulators which work on both sides of the upper arbor at a steady 45-55 PSI each. This careful attention to air and air pressure makes our quick response to major and minor cutting changes possible. That, plus the mechanical strain which is ever present as a back up system. Conventional strain for this unit is supplied by a pair of Belleville spring stacks acting through standard lever advantage on each side of the upper wheel arbor. The air strain system works through diaphragm type, non-sticking rolling action cylinders. These two straining methods are very compatible, mechanically, as each adjustable spring stack is integrated into its own diaphragm cylinder. With this ultimate 'fail-safe' system, losing a saw blade because air loss just can't happen. Our clean, uncluttered design also means quicker action by saw blade changing crews. Blade changing in less than five minutes is possible with this streamlined model. And you know what that means to the men from the filing room! Before any blade change, all air is purged from the strain cylinder insuring that the jack screw mechanism which lowers and rises the upper wheel is never subjected to high strain dynamic loads. The maximum recommended air strain with this unit varies from 12,000 to 60,000 pounds depending on the size of the band mill.

So, you might ask what are the advantages of Filer & Stowell's High Strain Band Headrigs?

Two in one strain mechanism. Operating saw strain is obtained through use of an air diaphragm system. As a safety feature, a mechanical spring strain system is provided to maintain a minimum saw strain at all times to safeguard against loss of air pressure.
A Bellofram diaphragm is used to provide the air strain. The Bellofram is a roll diaphragm which has less friction than any cylinder. This feature provide a more responsive strain system. The diaphragm is enclosed in two steel cylinders. this feature provides an advantage over air bag type strains in that the air bladder is contained. This eliminates the spongy response caused by the stretching of an uncontained rubber bladder, providing quicker damping time when the blade is displaced.
Filer & Stowell Sales Air Strain System uses normal mill air pressure through a precision air regulator/air relay. This system is more consistent and responsive resulting in longer saw life with less saw maintenance. No gases such as nitrogen are needed. Air volume is provided by an on-board accumulator in the even of large blade displacement.
When straining-up, strain automatically switches over from spring to air or back to spring when lowering upper wheel.
When raising the top wheel, the only load on the jacking mechanism is the lifting of parts (wheel, shaft, bearings, etc,). Then when strain is applied, all parts are stationary. The jacking mechanism sees only static loading promoting longer life.
F&S Sales shafts are over-sized for rigidity.
F&SS uses live shafts resulting in extended bearing life and less maintenance.
F&SS uses over-sized, double row, tapered roller bearings which are interchangeable from side to side and between shafts.
F&SS husk design places heaviest parts near the center of gravity to reduce vibration, resulting in the smoothest running bandmills in the industry.
Conversion from iron castings to steel construction was accomplished keeping the same mass for stability and ridigity and all weldments are oven stress relieved.
F&SS has over 100 years building sawmills, it is a time honored name.
Head saw filers and independent testing reports verify that F&SS Air Strain is the fastest reacting system in the industry.