How A Reduced-Weight Bar Affects The Performance Of A Pro Saw
Until just a few years ago, when a pro user purchased a new powerhead, he bolted on the same bar and chain he used on his last saw. These cutting attachments were not light. Most were a three foot section of solid steel. It was a strange marriage. With the powerhead, every ounce seemed to count, but little thought was given to bolting on a heavy guide bar. The reason for this was there was no alternative. Today, there is. Oregon Cutting Systems, Stihl, and Husqvarna all offer reduced-weight guide bars that are significantly lighter than a conventional guide bar. For example, an Oregon brand 32" reduced-weight bar weighs almost a third less than a conventional bar.
How A Reduced-Weight Bar Is Made
The Oregon lightweight guide bar is similar to a conventional bar in many ways. In fact, in the early stages of its production, it is no different than a conventional Powermatch bar. However, during the manufacturing process, when a conventional bar is ready for paint, a reduced-weight bar is only partially finished.
The bar on top is a conventional bar body. It could be finished and painted, but this one is destined for more machine work to become a reduced-weight bar. The bar below is similar to the one above, except it has been through a milling process where a portion of the steel in the center of the bar has been removed. Next, an aluminum insert will fill the area where the steel was removed.
The reduced-weight bar goes on to a milling machine where two pockets are removed to reduce weight. A thin strip of steel is left connecting the upper and lower rail sections. In the pockets, two lightweight aluminum inserts are glued in place with a special “aircraft-grade” adhesive. Rivets on each end of the aluminum inserts bind them to the center for additional support. The inserts are made of aircraft-grade aluminum. They restore a structural component that was removed when the steel pockets were cut in the bar’s body and fill the space.. Once the inserts are in place, both sides of the bar are ground flush on a surface grinder. There is no shoulder or gap between the aluminum inserts and the bar's body -- it is completely smooth. In fact, the overall thickness of a finished lightweight bar is slightly less than a conventional bar.
Stihl's lightweight bar is similar to Oregon's. The bar body is made of the same material as a conventional bar, but instead of milling out pockets on both sides of the bar, Stihl cuts a deep pocket from only one side. This is filled with a single piece of aluminum that is ribbed in the center.
In all lightweight designs so for, light-weight bars are not as stiff as conventional bars. This isn’t a problem for most users, but for a few, it is. The loss of rigidity combined with the fact that the body of the guide bar is no longer monolithic makes this bar a bad choice for saw operators who pry or “work” their bar. If you have a habit of “popping” out your undercuts, a reduced-weight product is probably not for you.
The Husqvarna bar is different from both the Oregon and Stihl bar. It is made of three separate pieces that are laminated together. Currently the Husqvarna bar is not available in lengths over 28", so this bar will not appeal to NW pro saw users who typically run 32" bars.
Improving A Saw's Balance
A standard 32” Oregon Powermatch bar with a Stihl bar mount weighs 4.7 lbs. on our digital scale. The same bar, in a reduced-weight version, weighs 3.3 lbs. This represents a weight saving of 29%. While these numbers are impressive, when a reduced-weight bar is attached to a powerhead, the result is more dramatic than most users expect. The reason is, some of the bar's weight reduction occurs quite a distance from the handlebars (balance point), so in addition to general weight savings, a reduced-weight bar improves the balance of the saw.
Here we are hanging two Stihl 460s from a clothes rack with a starter rope. Both are fitted with Oregon 32" bars. The one on the left is a reduced-weight bar and on the right is a conventional bar. This shows how the different bars affect the balance of the saws. The reduced-weight bar is a little less nose-heavy.
This is most pronounced when long reduced-weight bars are fitted to medium sized powerheads. On combinations like a Husqvarna 372XP fitted with a 32” bar, changing from a conventional bar to a reduced-weight bar gives the saw a more neutral balance. It no longer has a “nose heavy” feel.
For other users, the weight savings justifies using a larger powerhead or a longer bar. They can enjoy the power of a slightly heavier powerhead or the reach of a longer bar, while keeping the unit weight about the same as their old set up.
However you see it, weight reduction is a good thing. Lighter tools are easier on the user and can enhance productivity. Some users, with back and shoulder problems, have found a measure of relief by using a reduced-weight bar. Even more say a reduced-weight bar allows them to work with less fatigue, so there are safety benefits as well.
The Working Life Of A Reduced-Weight Bar
When this bar is used by a careful operator, the working life is similar to that of a conventional bar. We monitored the life of several lightweight bars and found that rail life is on par with a conventional guide bar. This is what we expected because the steel portion of the bar is #4130 tool grade steel; the same used on all Oregon® Powermatch bars.
What will shorten the life of a reduced-weight guide bar is damage. Like a conventional bar, a reduced-weight bar will survive a slight bend or tweak. It can be easily straightened in a cut or press. Severe bends are another matter. These will break the laminations, which ruins the bar.
The Future Of Lightweight Bars
Today's reduced-weight bars sell for about twice the price of a conventional bar, which we believe is an upper price limit. We also believe evolving technology along with modern manufacturing methods will yield cost-effective weight savings in the future.
Research has shown that cutting attachments could be even lighter, but high-tech materials like titanium and carbon fiber are expensive, which makes their use prohibitive. If the future is anything like the recent past, materials like these will come down in price. New ideas and manufacturing methods should also lead to cost effective ways of making even lighter bars.
• Experienced pro saw users will like running a reduced-weight bar. These bars reduce the overall weight of a pro saw while improving its balance.
• Reduced weight bars from both the Oregon and Stihl have proven to be durable and long-lasting.
• If you are just learning to cut or have a tendency to be hard on your bar and chain, a reduced weight product probably isn't for you.