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Late-winter bar exam
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Pointy sprocket teeth and chips in the bar rails spell the end for this chain saw bar. If the rest of the bar is OK, this pro-style bar nose can be replaced. Photo by Scott Nesbitt |
Give your chain saws a bar exam while waiting for the last signs of winter to finally fade away.
Bring all your chain saw bars to a warm, well-lit room that has a flat and level table. It’s OK to sip cocoa while doing this.
Stack the bars up on the table and eyeball the pile from the side. Curved or twisted bars will show an air gap above and below. Rearrange the stack a few different ways, alternating the tips and butts.
Perfect flatness is rare if a bar has some field usage. Bars are a highly engineered product, and are made to spring back after minor flexing. A permanent curve or warp increases wear on both the inside of the bar rail and the mating face of the chain. Any bar that makes the stack unstable is a scrap.
Stand each bar up on its rails. It should stand up at 90 degrees on a flat, level surface. A bar that falls over has uneven rails.
Check tipsy bars closely, looking down the length for bad spots where the rails pinch together or spread apart. Look down the length, checking for straight parallel rails. You may notice that the outer edges are developing knife edges. This is from excess friction. Your chain was too tight; your saw’s oiler is weak, is adjusted for too little output or has a plugged filter. You may be using the wrong bar oil or the oil was too thick for use in extra-cold weather.
You can use an exceptionally good file to clean minor knife edges off the rails. You may also be able to clean up tiny pits. But be warned: Bar rails are super-hard steel and will ruin a file pretty quickly. And few humans can do the job with a whetstone.
Examine the bar noses, which take the most abuse on any chain saw. If it’s a hard-nose bar, check for knife-edges and broken chunks.
If there’s a sprocket in the nose, it is supposed to lift the chain slightly above the rails of the bar to eliminate bar-to-chain contact. If the sprocket teeth are worn to sharp points, you’ve got excess wear. Many professional-grade bars have replaceable noses. Leave nose installation to a service shop that has the “bar tender” machine to grind, level and polish the rails and verify that the bar groove has enough depth to clear the bottom of the chain-drive links.
You can probably get a price break if you bring your saw specialist a no-rush batch of bars that need cleaning or replacing, along with chains that need to have their teeth restored to equal length and proper angles. It will be easier to field-dress the chains if the chain teeth start the season in good shape.
And you can look forward to an easier job cutting deadwood and clearing dropped limbs when that snow finally goes away.
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