Bar maintenance is a very important in the operation of today's high speed, high-horsepower saws.

Stop for a moment and think about how much chain is traveling around the bar in one second's time. About 80 feet of chain passes one spot on the bar in one second. Over an hour's time that amounts to almost 300,000 feet or 53 miles of chain. Given this speed and the light lubrication that the chain and bar receive, both the bar and chain will wear during normal use.

Where conditions of abnormal wear exist, they are often the result of poor maintenance practices. The faults are usually poor sharpening of cutters, loose chain tension, or inadequate bar and chain lubrication.

The wear pattern on the bottoms of cutters, tie straps and drive links generally reflects the condition of your bar. Regular inspection of the chain will point out the need for corrective maintenance. Correct problems immediately and you can avoid further damage or premature replacement of the bar or chain, or both.

Here are some examples:

1. If the bottoms of the drive links are worn flat, like the shaded area, the bar groove is shallow either in the tail or straight section of the bar. (see A)

2. If the bottoms of the drive links are worn concave, the bar groove is shallow in the bar nose. Most likely, the wear resistant alloy material on the hard-nose bar has worn off. (See B)
3. If the bar rails are not flat and square, the chain parts will wear like exhibit C below.

4. If the bar rails are uneven, the chain parts will wear like exhibit D, above.

How to check bar groove wear:

First, tension the chain. Then, place a straight edge against the bar and the cutting edge of one cutter. Force the cutter sideways as far as it will go. There should be a 1/16 – 1/8-inch gap between the straight edge and the side of the bar. The chain should be supported squarely by the bar rails. If it isn't, it's time for a new bar.
(See E, below)

To get better service from your bar, check it daily for the following:

1. Bar rails flat and even. Both rails must be flat and square with the sides of the bar. The original shape or contour of the bar must be maintained. (See F)

2. Correct bar groove width and depth. The groove width should be from .002" to .005" wider than the gauge of the chain being used. Groove depth should range between a minimum of 5/16" and a maximum of 27/64". (See G)
3. Check your bar by sighting down it to see that it is straight. A bar can be bent in an operating accident and the user will not be aware of it. Bent bars should be straightened immediately or further damage will occur to both bar and chain.

General maintenance techniques:
The chain and bar operate together as a team. A few simple practices can make them both run efficiently.

1. Keep your cutters sharp by filing frequently.
2. File the cutters evenly. Be sure the filing angles are the same on the left and right sides.
3. Keep your depth gauges even on both sides of the chain at their recommended settings.
4. Use plenty of bar and chain oil. Oil is cheaper than a new bar or chain!
5. Remove the bar periodically and clean accumulated sawdust from the oil hole and bar groove. Turn the bar over regularly.
6. Tension the chain properly. The chain should be tight enough to pull around the bar by hand. Check the tensioning frequently, but not while the chain is hot; wait until the chain is cool to the touch.

At a speed of 53 miles per hour, four hours of saw running time means 200+ miles of chain passing over the bar. Attention to the condition of the chain and bar, plus frequent lubrication, will safeguard your equipment investment. In reduced wear alone, you'll more than pay for the oil you use.

You're trying to get some work done in the yard, and the trusty old chainsaw is acting funny; here's what to do when: Chain won't turn – Check for: Tension too tight Burred drive links Pinched bar groove Chain off sprocket Bar sprocket nose frozen Chain brake engaged Adequate bar/chain lubricant Debris (chips) in bar groove or drive sprocket Slow cutting – check for: Dull cutters Depth gauges too high Clutch slipping Bar groove too wide And, believe it or not, chain on backwards Chain cuts crooked – check for: Low depth gauges on one side Uneven bar rails Cutters filed differently, one side to the other Damage to cutters on one side of chain from hitting the ground, a rock or other foreign material Finally, although we don't manufacture saws, we spend a lot of time with them, and when your chainsaw won't start.... here's what we always check : Ignition switch on Choke on Air filter clean Spark plug clean, gapped Plug wire on Saw gas in fuel tank Having trouble with chain sharpening, remembering the correct angles, and so forth? You can get a free copy of our Maintenance & Safety Manual, with all the right info, just by e-mailing your snail-mail address to technicalservices3@oregonchain.com and mentioning "MM."	Chain won't turn? Check to make sure the chain tension is set correctly.
	The front of your chain's cutters should always face and drive towards the tip of your bar.

Because it is tougher to cut frozen wood, an operator will have a tendency to apply more pressure on the saw chain and bar. In addition, because oil thickens at cold tempertures, it is difficult to maintain an adequate supply of bar-chain lubricant to the chain and bar. The result is increased wear on bar rails and on the bottoms of chain cutters. This excessive pressure also puts extra strain on both the saw motor and the user. Generally, winter cutting is similar to winter driving. You drive on icy roads with extra caution and attention to your automobile. It's also important to give the same care to your chain, bar and saw.

Winter Chain Saw Use Guidelines

• Cutters: Keep cutters sharp. Touch up every hour, more often if needed. Do not force dull chain to cut.
• Depth gauges: Check and adjust your cutter's depth gauges at every sharpening. It is not uncommon for top-plate breakage to occur with low depth gauges in conjunction with frozen wood.
• Bar: Keep the bar groove clean and the oil hole open. Turn bars over to equalize rail wear. Chain and bar wear will occur if oil is not allowed to pass freely from the saw.
• Drive sprocket: Replace the sprocket after every two chains, or sooner. Chain stretch is often the outcome if too many chains are allowed to run on a worn sprocket.
• Tension: Keep your chain correctly tensioned. Check and adjust often. Loose chain tension is a very common reason for premature chain and bar wear.
• Oil: Use lightweight bar-chain oil and be certain your chain is receiving oil from the saw. If needed, you can dilute your summer oil with up to 25 percent of clean kerosene or diesel oil. You should use up to twice as much of this diuluted oil during operation. Because they are friendlier to the environment, biodegradable lubricants are suggested as an alternative to traditonal mineral-based oils.
  
  When cutting in snow, clear as much as you can away from the cut. Snow will melt from the heat of your chain and bar, which will wash away the oil.

Keeping Top Plates Equal Have a look at your used chain; are the top plates on one side consistently longer than on the other? If so, that means you're probably more comfortable sharpening the short side; it feels natural and so it gets more strokes. Next time you buy a new chain, make a point to start sharpening on what was the long side of the used chain, count the strokes, and do the same on what was the short side. You'll have a better chance of keeping the top plates equal, and your chain will cut straight.

Greasing Bar Noses Like any machine with precision bearings, bar sprocket noses benefit from frequent greasing. We suggest tying a grease gun to your gas can. Every time you fill your saw with gas, grease the nose of your bar.

Files and Grinding Stones Thoroughly cleaning your chain prior to filing or grinding will insure longer file life and less cutter burning while grinding. A wire brush works well for this job.