Self-sharpening chainsaws have been around for over fifty years with the earliest models emerging in the 1960s. Self-sharpeners have made periodic come-backs, but have never gained massive popularity, likely because most models tended to be less effective, and/or attached to an inferior saw. Despite an early lack of success, the regular resurgences certainly confirm what most saw users already know: hand sharpening a chainsaw chain really sucks and nobody wants to do it. Oh, there are a few people out there who truly love spending some quality time with their chainsaw and a file, but for most of us it is a brutal chore.
The Worst Chainsaw Chore: Hand Sharpening
Every chainsaw operator is familiar with that sinking feeling when you let the saw settle just a little too close the ground and seeing dirt kick up. We inevitably cross our fingers and apply the saw to the next cut only to see that fine powder, blue smoke, and slow cutting speed to tell us that the teeth of our chain now more closely resemble bumps on a log than finely tuned cutting machines. After a loud string of curses, we kill the saw, thump it down on a log and haul out the hand file. Hand filing a chain is a mind numbing and aggravating experience even for those who are particularly talented at it. The first frustration is the simple fact that you are sitting in the bush doing basic maintenance when you should be cutting. Down-time like that is annoying whether you are a do-it-yourselfer, or a professional for whom time is money. Hand filing itself comes with its own little frustrations. For those who are less practiced, there is the regular slipping and barking of knuckles on the chain and bar. Getting the angle just right requires practice and a sharp eye. If you managed to actually clip a rock, you are in for an extended session of a repetitive task that requires your full attention. Misfiling a chain can result in even poorer cutting performance than a dull chain. Basically, hand filing is a time consuming, uncomfortable, and uncertain process.
This is undoubtedly why the self-sharpening saws made regular comebacks despite repeated failures. The original self-sharpening saws had a sharpening stone built into the clutch cover. For those who are not familiar with the anatomy of a chain saw, this is in the general area where the chain goes into the main body of the saw, around a sprocket, and back out onto the bar. Essentially, the placement of the stone meant that it could be applied to the outside of the chain as the chain ran past it and therefore sharpen as fast as the chain is moving. Recently, some major chainsaw manufacturers are bringing back the self-sharpening concept, complete with modern technology.
Oregon PowerNow with the Power Sharp Sharpening System
This small battery operated chainsaw from Oregon (click here for a review) was developed several years ago with a built-in Power Sharp sharpening system. The saw itself is considered a significant advance on previous battery-operated models for both power and battery life. It is designed for smaller, lightweight jobs and comes with a small 14 inch bar and chain. The sharpening system requires a special chain that sharpens from the top down rather than sharpening the underside of the tooth. This chain has the added features of an extra guide link after each tooth to help ensure that the cutting teeth are well supported when they contact the stone and a diamond-coated dresser link to resurface the stone, ensuring that the sharpening angles remain the same. Oregon created a thicker top plate on the tooth to make top sharpening functional, addressing the concerns of several users around chain life. Like the older self-sharpening models, the Oregon PowerNow has a honing stone built in where the clutch cover would be on a traditional gas saw. There is a lever attached to this stone that extends up through the housing to the top area of the saw. When the saw chain is getting dull, the operator simply pulls this lever to engage the stone with the chain while holding the throttle wide open. The stone contacts the chain as it comes around the sprocket and hones the top of the cutting teeth as well as reducing the height of the guide links and rakers appropriately to maintain chipping ability. An entire sharpening process takes less than five seconds. After several years of trials and public feedback, minor alterations have been made to the system, but overall it has proven effective. One glitch that was noted was the increased potential for a buildup of dust and chips around the sharpening stone under the housing which can create friction and bog down such a small saw. This was only an occasional problem, but users should be aware of it. This particular saw is quite small and is really designed for occasional and light uses, not for professional day-to-day hardship.
The External Power Sharp
However, Oregon has created and marketed the PowerSharp sharpening system in a somewhat larger capacity to fit many larger saws. This system includes a bar, chain, and detachable honing section. The special bar has two pin holes in it near the tip. When the saw is dull, the honing device fits onto these pins and locks around the tip of the bar. In this position the stone is sitting just off the tip of the chain. To sharpen, the operator turns on the saw, holds the throttle open, and pushes the now covered tip into something hard until they see sparks. Hold this for three to five seconds and release. Remove the stone and cover and the chain is ready for more cutting.
This system is only available in certain sizes and so in many ways is not ideal for professional applications. Operators with multiple saws often run one with a Power Sharp system to allow them have a sharp saw in less than two minutes if they are in a hurry. On the other hand, there are some who argue that a self-sharpening system will never beat a good hand filer, and that people who cannot file their own chains should not be operating chainsaws. As with most new products there is nothing approaching a consensus around the Power Sharp system. It may well be suited for the occasional user or for those who are not well versed in hand filing their chains. It would likely be ideal for small pruning jobs or dirty work requiring a lot of sharpening. Having said that, some people prefer working with a more traditional chain which allows them greater control over the angle on their saw teeth and the height of the rakers. Power Sharp is not for everyone, but it is an option worth considering. Beyond the Power Sharp system, most chainsaw operators will remain reliant on hand filing in the field. Guides and jigs can help ease some of the frustrations, but at the end of the day it will be sweat and curses that get you through.