Any list of frustrating, and sometimes maddening, experiences on a tree care work site would probably include inattentive ground crews, ropes that are just a hair too short, poorly placed skylights, and poorly maintained or dull chain saws. Of all these experiences, the one that tree crew members can most easily fix, short of choosing another profession, is that of poorly maintained or dull chain saws.
A “bad” saw not only decreases efficiency and increases blood pressure, making nobody on the crew or in the office happy, it can also have a serious effect on the safety of the operation. A poorly maintained or dull saw can throw a chain, die in the midst of a very “touchy” cut, or make the operator spend too much time thinking about the saw instead of the fact they’re in a precarious position 60 feet in the air running a piece of equipment that removes organic material, including flesh and bone, at a high rate of speed.
Unfortunately, proper saw maintenance and chain sharpening are often neglected tasks. However, regular maintenance and sharpening will have immediate positive benefits on crew production, safety and, yes, happiness. A comprehensive conversation of chain saw maintenance would fill a book, and in some cases already has, thus it’s beyond the scope of this column, but a few basic ideas and practices will help make better saw maintenance and sharpening a reality.
The bar. No, not that one
The bar of a chain saw needs to be cleaned out regularly to get all the old bar oil, dust, chips and associated debris out of the channel that the chain runs in. The best way to accomplish this effectively is to use a bar cleaner from the tip of the bar to the rear. Going in this direction will also keep all the “junk” from becoming packed into the sprocket on the nose of the bar, generating yet another maintenance issue. It should be done regularly to prevent the natural heat buildup of the bar from “cooking” all that oil and debris into baked brownies from hell inside the channel of the bar and on the rails, interfering with clean and efficient chain movement and rotation.
The oiler hole at the rear end of the bar is where the bar oil accesses the chain and rails, so making sure it is clean and clear at this time should be part of the bar cleaning process. Flipping or rotating the bar will help even out the wear on it from chain movement, so flipping it at cleaning is an easy way to make sure this is done regularly.
Any burrs or obviously rough edges on the bar should be removed with a flat file, and the bar inspected to make sure it is straight and true. Bars are often bent by frustrated operators trying to lever a pinched bar out of a cut. The easiest way to check bar straightness and trueness is to lay it on its side on a flat surface. The bar can then be set on edge to make sure the tops of the rails are even and level. If the top of the rails are uneven, it can often be fixed through the judicious use of a flat file, but trueness corrections may require a visit to a shop, depending on what tools are available at the tree company.
Look inside … the saw
Taking off the side plate regularly and inspecting and cleaning around the area of the drive sprocket will go a long way toward keeping a saw happy. The channel or hole that the bar oil reaches the bar from should be closely checked and cleaned. The cover also should be cleaned and checked. In smaller saws with an external chain brake, the band of the brake needs to be checked for cracks and cleaned to ensure proper function. Most smaller saws will have a spur-type drive sprocket, while larger ones will have a rim drive. Both should be checked for wear and function and will need replacement periodically. Manufacturers recommend that a new sprocket be put on once three new chains have been worn out on it, along with replacement of the bar. This helps promote more even wear on the respective pieces and parts while increasing the drive efficiency of the saw.
Most saws will have needle bearings back behind the sprocket that should be lubed with white lithium grease, either through the available grease fitting, or by removal of the clutch drum and sprocket to access the bearings.
Are you tense?
Chain tension is something that everyone has an opinion on, but regardless of the opinion, proper chain tension is important. It effects efficiency and bar wear and increases the likelihood of thrown chains. The easiest method to adjust the chain tension correctly is to loosen the bar nut(s) and flip the saw over onto its top. This lets gravity do the work of moving the bar to its proper place for chain adjustment. The adjuster can then turn the tension screw until the chain comes in contact with the bar, and then give it another quarter turn. Then tighten the bar nut(s) and turn the saw right side up. If little divots or half-moons are seen in the bottom of the bar near the tip, the chain is being run too loose and is “slapping against the bar as it rotates around at a high rate of speed.
Even saws need to breathe
If a saw is not running well, the first thing to check after fuel is the air filter. In addition, regular inspection and cleaning will go a long way to keeping saws performing correctly. The air filter type will differ with model, size and manufacturer. Filters are typically made out of fine plastic mesh, flocked paper or foam pre-filters that wrap around the primary. In the field, users are pretty much limited to knocking them out and removing as much dust and debris as possible. The availability of tools such as compressed air or brushes means the cleaner should use care not to poke holes in or otherwise damage the filters. Warm water and soap followed by air drying is a good way to clean air filters if possible. The plastic filters will be squeaky clean after a run through on the wash cycle in the dishwasher, but the heat of the dry cycle is a bad idea. Creative climbers may wish to wash their climbing helmets in the dishwasher at the same time, thereby accomplishing two hygienic tasks at once.
Adjustments, adjustments, adjustments
Both bar oil and carburetor adjustment will require a small, typically standard, screwdriver. This tool is one of the most difficult to keep track of due to its size and its tendency to migrate readily. Air quality concerns and regulations limit the amount of carburetor adjustment that is possible on modern saws, typically through installed limiter caps, and this is unlikely to change or get better anytime soon. Before making any adjustments, the operator should make sure the saw is clean, especially the air filter, and that fresh mix is in the fuel tank.
Following the manufacturer’s guidelines is an excellent place to start, particularly as a poorly adjusted saw can be fatally damaged, and manufacturers tend to frown on warranties that have been violated in such a way.
A hand-held tachometer allows users to adjust the RPMs to exactly what is specified. The adjusted saw should idle well no matter what position it is held in, and there should be no movement of the chain at idle with the chain brake off. Bar oil is imperative for the long-term health of the bar and chain and can radically affect short-term cutting efficiency. The adjustment screw is most often on the bottom of the saw and is usually marked with the symbol of a drop of oil and a chain saw tooth.
Tools. No, not you, for the saw
There is a veritable cornucopia of tools available for chain saw maintenance and sharpening. They range from simple file guide systems to an “all-in-one” tool such as the Top Saw Pocket Wrench, which even functions as a handle for a round file. A basic chain saw maintenance tool kit should include a bar cleaner, a scrench (handy screwdriver-wrench that comes with most saws), flat file, correctly sized round files for sharpening, some form of guide system for both cutting teeth and depth gauges, small screwdriver for adjustments, Torx head for Stihl bolts, and an Allen wrench for Husqvarna bolts. Additional tools that could prove use- ful include the afore- mentioned hand-held tachometer for carburetor adjustment, a bar dresser and a stump vise for field sharpening/maintenance. A couple of old toothbrushes or paintbrushes can also be useful for cleaning those hard-to-reach areas, but remember to use care with the air filter.
As the title says, chain saw maintenance is not necessarily exciting, though more than a few “motor heads” find it mildly enjoyable. Regardless of the excitement level, regularly cleaning and maintaining your saws will help keep crews running more smoothly, more safely and more happily, at least until they discover the rope is indeed too short, the ground crew is still not paying attention, and that skylight.