File comfortably

must learn to file before the chain gets dull.

Both hand and electrical chain filing can give good results. The electrical is faster and simpler. For hand filing, we recommend a double file with a built-in filing gauge. (Pferd 4 mm, part. no. 9999-000-0400).

It is much easier to sharpen the chain if you have a proper work place. Fasten the guide bar in a screw vice or a saw clamp.

Best is to build a table next to the sawmill for filing and other chain-saw maintenance. If you have an electric saw, you will need a file block (part. no. 9999- 000-0620) to hold the chain during filing.

Avoid chain breaks

If you saw too long with a dull chain, it can break under the cutter where the material is worn.

If, on the other hand, a drive link breaks the reason can be that the chain and the sprocket are not matched. For best results you should alternate five chains on one sprocket. When the chains are worn out, replace the entire set, including the sprocket. A new chain placed on a worn down sprocket can break during the first few minu- tes.

It is not good to drive a normal 3/8” chain and a PMX chain with the same sprocket.

The guide bar can pull askew

If the chain has been damaged on one side or filed unevenly, the guide bar can steer askew. The guide bar will be pressed up or down or jumps when it

leaves the log. This way the chain wears more on one bar rail and if you continue to saw, the guide bar will be worn lopsidedly. Even if you change the chain, a worn down guide bar can steer wrong and the new chain can be worn down. A lopsided guide bar can be fixed. File the bar rails until they are even, using a tool like a UKF file (part. no. 9999-000-0450). Another, more common reason that the guide bar pulls askew is that it is so worn out that the drive link bottoms in the bar groove and the chain looses its support from the guide bar walls. This can be seen on the chain in that the tip of the drive link becomes worn.

The best chain oil

In order for the chain oil to work well it must be viscous and thready. When you place a drop between the thumb and the index finger and then open them, long threads should form.

Edge in the chromium layer

The cutter on a chain-saw chain is covered with a very thin chromium layer, giving a very sharp and durable edge.

As long as the edge is in the chromium layer, your chain will have perfect sharpness. However, after between 50 and 100 cuts with the M7, the edge in the chromium layer will be worn down. At that point it is time to file the chain. If you are really sensitive, you will notice that the chain slows up, the guide bar heats up and the feed pressure must be increased. If you file as soon as you sense that the chain is no longer perfectly sharp, you will need

only a few, light pulls with the file.

If you always file before the chain becomes dull, wear on the guide bar and chain will be minimal.

However, if you make 5-10 cuts after the edge has left the chromium layer, the chain will be so dull it will be difficult to saw. The sawing speed will be low and the feed pressure high. The guide bar and chain will easily overheat. It is still possible to saw, but the equipment will wear out very quickly.

When you file a chain, there is a real danger that you won’t reach the chromium layer. The chain may feel sharp, but because it isn’t in the chromium layer, it will become dull again very quickly. If you don’t file in time, you will have to remove a lot of the cutter to get it sharp. The working life of the chain will be short. And if a lot of the sawing is done with a dull chain, you will need a high feed pressure, with consequent rapid guide bar wear and a high risk for chain breaks.

In conclusion, file before the chain is dull so that you avoid getting into a vicious circle where the wear on the sawing equipment increases and the sawing result goes down.

Regular chain sharpening is especially important if you are sawing wood that is aggressive to the chain, such as dry material, hard wood or wood with sand or earth in the bark.