Most, if not all, tree care professionals are familiar with the frustrating, and oftentimes enraging, process of attempting to start and work with a poorly maintained or dull chain saw. This process, besides affecting the climbing arborist’s emotional and mental health, also has an immediate effect on efficiency and production output; after all, it is quite difficult to be “lookin’ good, cuttin’ wood, in the ‘hood” with a chain saw that refuses to start, gnaws through wood at a maddeningly slow pace, or seems to maintain the proper idle only when some unknown stars and planets are in proper alignment.
Beyond inefficiency and lack of production, a case can also be made for the view that the operation of neglected chain saws is more dangerous, as they can throw chains, decide to die in the midst of critical cuts, or simply distract their operator’s focus when involved in an activity that requires the utmost in concentration and attention. In short, regular and proper chain saw maintenance and sharpening will have immediate positive benefits for any tree crew that implements a regular program.
A complete and comprehensive discussion on chain saw maintenance and sharpening would take much more space than is available within the scope of this column, however, a regular program that includes some of the following basic practices and techniques will result in better saw performance and efficiency.
Bar cleaning and maintenance: Chain saw bars should be cleaned regularly to remove all built-up wood debris, excess bar oil and dust by running a bar cleaner through the bar rails from the tip to the rear. Going in this direction will prevent the debris from being packed into the sprocket at the tip of the bar, interfering with its rotation; doing this regularly will help stop the possibility of the material “baking” on in the extreme heat environment, thereby interfering with the chain running cleanly and efficiently between the bar rails.
Particular attention should be paid to the oiler hole in the bar, as it is the opening through which the bar oil reaches the chain and is spread along the length of the bar. Additionally, regularly rotating or flipping the bar will help ensure even wear on both sides throughout its life on the saw. The bar should be inspected for burrs and, if required, a flat file used to remove them. The top of the bar rails should be even, and the bar itself straight and true, something often affected by the habit of attempting to lever a pinched bar out of the cut.
A simple way to inspect both of these is to use a flat, even surface, lay the bar on its side to check for straightness and trueness, while setting it up on edge to evaluate the even nature of the top of the bar rails. Uneven bar rails can be corrected through the use of a flat file, while the bar’s trueness may require a visit to the dealer for straightening, although there are tools available such as bar rail closers for this operation.
Side plate removal/chain or bar removal: The side plate should be removed regularly and the area around the drive sprocket inspected and cleaned. Particular attention should be paid to the channel or opening through which the oiler oils the chain and bar.
Saws with an external chain brake band, typically smaller saws, should have the band cleaned well, as the material and debris building up on and around the band can interfere with its proper operation. Climbing saws typically will have a spur sprocket, while larger professional saws will have a rim drive sprocket. These should be inspected for wear and functionality and replaced if required.
Most manufacturers recommend that the chains, bar and sprocket all be replaced at the same time so that they wear evenly and in conjunction with one another.
The needle bearings beneath the sprocket should be lubricated with white lithium grease regularly. Some models will have a grease fitting to allow external lubrication, while others will require the removal of the clutch drum and/or sprocket to access the bearing assembly.
Chain tension adjustment: Proper chain tension will not only help increase cutting efficiency, but also lessen the likelihood of thrown chains and adverse bar wear. One of the simplest methods for proper chain tension adjustment is to loosen the bar nuts and then put the saw on its top, allowing gravity to do the work of lifting, or in this orientation lowering, the tip of the bar, adjusting the tension with a large screwdriver until the tie straps contact the bar, and then giving the tension screw an additional quarter turn. The bar nuts should then be retightened prior to turning the saw back over.
The appearance or existence of a small divot or half-moon shaped mark near the tip of the bottom of the bar is indicative of a loose chain. The chain is slapping against the bar as it rotates around, wearing away at the metal.
Air filter cleaning: The air filter should be cleaned regularly and always checked initially in the event of poor saw performance. The type of air filter will vary with the saw and manufacturer, but will include fine plastic mesh screens, flocked cloth-type materials and sometimes flexible foam pre-filters that wrap around the primary air filter.
Field cleaning is typically limited to knocking out as much debris as possible, and care should be taken to not grind materials into the filter by attempting to use brushes or poke holes in the filter through the use of too much compressed air or abrasive tools. Warm water and soap followed by air-drying is an excellent way to clean filters if this capability exists.
Carburetor/bar oil adjustment: A small standard screwdriver is required for carburetor, and often bar oil, adjustment. Due to air quality concerns and regulations, the amount of carburetor adjustment available to operators is fairly limited through the manufacturers’ use of limiter caps.
Prior to performing any carburetor adjustment, tree crew personnel should make sure the saw is clean, particularly the air filter, with fresh fuel appropriately mixed in the fuel tank. Care should be taken when adjusting the carburetor and manufacturer’s guidelines followed, as an improperly adjusted saw can easily be permanently and fatally damaged.
The use of a hand-held tachometer will allow operators to “dial in” the RPMs to the recommended setting. A properly adjusted saw should idle well in all positions, with no chain movement with the chain brake disengaged. The proper amount of bar oil reaching the chain and bar is vital to their long-term operation. The adjustment screw is typically on the underside of the saw, depending on manufacturer, and is often marked with a diagram of a cutter tooth and a droplet of oil.
Sharpening: This topic is worthy of a whole book in itself, yet a few basic principles may be helpful. The use of a guide will help ensure the proper angles for sharpening, and typically result in the most well-sharpened chain, but determined freehand field sharpeners can use the witness mark on the back of the cutter teeth as an approximation of the proper angle. This mark is intended to alert users to when a chain should be taken out of service.
Sharpeners should be sure that they are using the appropriately sized file for the given chain, as improperly sized files, either too big or too small, will be detrimental to the sharpness and longevity of the chain. Additionally, depth gauges, often referred to as “rakers,” should also be filed down in conjunction with their respective cutter teeth. The depth gauges should be filed with a flat file, and should be “tuned” to the height of their individual cutters; thus, some form of guide is best used. There are some guides available that will sharpen the cutter teeth and take down the depth gauges at the same time.
Tools: There are a wide variety of tools available for the various and sundry tasks of chain saw maintenance and sharpening, some of which are shown in the accompanying photographs. Those that will be useful in the maintenance activities discussed here are a bar cleaner, a scrench, flat file, an Oregon or Pferd bar dresser, file guides, depth gauge guides, small screwdriver, Torx head for bolts on Stihl saws, Allen wrench for bolts on Husqvarna saws and, a new addition to the chain saw maintenance tool scene, the Top Saw Pocket Wrench.
Although chain saw maintenance and sharpening may seem mundane to some tree care professionals, activities that they did not get into the industry to do, a regular practice of cleaning, maintaining and sharpening saws cannot help but assist all tree crews in their endeavors to be safer and more efficient.
Michael (House) Tain is a contract climber, splicer, educator and writer associated with North American Training Solutions/Arbor Canada Training and Education, currently located in Lancaster, Ky.