How to Sharpen a Chainsaw

Many preppers are happy when they buy a chainsaw thinking it will be of tremendous help in various SHTF situations. But very few remember to plan for sharpening their chainsaw. Using a blunt chainsaw is a waste of time and energy, not to mention a safety hazard.

Just like any piece of machinery, your chainsaw needs regular maintenance to keep it in tip-top condition. In theory, cutting clean wood all the time doesn’t require sharpening as often, but that’s just theory.

We don’t live in a perfect world. The reality is that wood you want to cut is often dirty and lying on the ground. You won’t be able to prevent your saw from coming into contact with rocks and grit that can dull the blades. That’s just a part of life.

How Do I Know My Chainsaw Needs Sharpening?

Here are some of the tell-tale signs to look for:

  • The saw throws out dust instead of nice clean wood chips
  • The chain looks shiny – if the chrome plating has worn away, it will expose the steel underneath and look shiny.
  • The chain is not self-feeding and you are having to apply force to get it to cut

Your chainsaw should always cut as well as it did the day you bought it or at least as it did last time you had the chain replaced.

Using extra force to make the dull chain cut will put unnecessary pressure on the guide bar, sprocket and chain and wear it out quicker. That’s why it’s really important that you stop cutting if you notice the saw is dull.

Using a blunt chain is physically exhausting to the operator and may well result in fatigue related injuries to yourself or others – another good reason to stop and sharpen up. Manufacturers always suggest that you buy the correct brand of chain for your machine if you are replacing the chain or bar.

So let’s see exactly how to sharpen a chainsaw…

Understanding Your Chainsaw

In layman’s terms, the cutting action of a chainsaw is caused by individual plates which act as chisels across the grain of the wood. Right and left hand cutters work alternately on each side of the chain to gouge out a neat cut at a speed of approximately 60mph.

A chainsaw cutting tooth is shaped like a ‘7’ and has three different angles: the top plate cutting angle, the filing angle and the side plate angle. These angles will vary according to what type of chain you have, however they all need to be very sharp to give the best result.

It is worth noting that if you are replacing a chain that is several years old, the new one may not necessarily mesh smoothly with the sprocket and bar. It will probably cause rougher cutting and more wear and tear on the saw.

It is wise to take at least two if not three spare chains with you at the beginning of the day. That way, when one becomes dull you can easily just swap it over for a sharp one. This will confine your sharpening activities to the workshop and save you a few headaches trying to do it in the field.

However, if you are caught out and have to sharpen one on the run, it is not hard, just a little more time consuming.

Chain Needs Sharpening? Let’s Get Started!

Gloves are a must when handling chainsaw chains – the cutting edges, even if blunt for cutting wood, are still treacherously sharp and can easily make quick work of your hands. Leather safety gloves are your best choice.

Any adjustments made to your chain should only be done once it has cooled. If changes are made while it’s still hot, it may bind and require further correction once it has cooled.

You need to determine the gauge of the chain on your saw and select a file that matches the size of tooth. It’s crucial to select the right size file for your chain – it is wise to consult your owner’s manual before you embark on filing.

If the file is the right size it will fit snugly into the curve of the cutting plate and about 20% of the diameter will be above the top plate. Using a file that is too big will put a back slope on the cutter, which means that it won’t feed properly. You will have to force such a chain to cut.

When filing by hand it is difficult to maintain perfect consistency of angles without some type of a file guide. Perhaps the easiest type of guide to use is one that drops over the chain and keeps the file at the right angle and height. These guides also have witness marks which correspond with the guide-bar plane, to show the correct top-plate angle alignment. There are other types of guides which can also be purchased, but again, make sure that yours is the correct size for your chain.

While using a guide may make the filing process take a little longer, the end result is probably going to be more pleasing, so it’s worth it.

Ok. So you have determined the size of the file you need, put on your gloves and are ready to go.

Whether you are at home in the workshop or performing this job out in the woods, the filing process is the same. The following steps will tell you how to sharpen your chain with a round file.

11 Steps To Filing Your Saw

NEVER turn the saw on while you are sharpening to rotate the chain – only move the chain around by hand.

  1. Find a level, well-lit place to carry out the filing process. Of course a workshop is the ideal place, but if you are bugging out, why not use a level tree stump as your workbench?
  2. Make sure the saw is turned off and, as an extra safety measure, remove the spark plug wire
  3. Carefully examine your chain for:
  • Broken rivet heads or loose rivets
  • Worn or broken teeth
  • Broken tie-straps
  • Bent drive links
  • Correct chain tension – the chain should be firm against the bar, but still should still pull easily around by hand
  • If you find broken parts, stop now and take the machine to a service dealer for replacement parts or entire chain replacement.
  1. Make sure the chainsaw is steady and the bar isn’t rocking up and down. If you need to, place a wooden block under the bar to support it and hold it level.
  2. Use mineral spirits or some kind of degreasing agent to thoroughly clean the chain and remove the grit and dirt. Obviously you will want to make sure you don’t flood the whole engine, since some of these products might damage the plastic housing of your chainsaw.
  3. Try to locate the leading cutter and use this as a starting point. The leading cutter is often shorter than the rest of the cutters on the chain. However, if they all seem to be the same size, you can just start anywhere. Mark the place you start with a paint pen so you’ll know when you get back to where you started.
  4. The teeth that are pointing toward you are the ones that you will be starting with, so drop your file into the notch at the front of the cutter. There should be arrows marked on the filing gauge – make sure that these are pointing in the same direction as the chain rotates.
  5. Hold the file with both hands and file the cutter from inside to outside, applying a gentle amount of pressure. Release pressure on the return stroke, remembering that the file only cuts in a single direction. Never force the file – if the size is correct it should slide easily across the cutting teeth.
  6. File until the cutting edge looks uniform and there are no patches of colour on the blade. It is a good idea to count the amount of strokes you do on the first tooth, then use the same amount on each tooth thereafter.
  7. File all the cutters on one side of the chain first, then turn the whole saw around and repeat the process on the other side.
  8. It is important to sharpen all cutters equally. If one cutter has a particular amount of damage, you will need to start with that one and file until all the damage is removed, then sharpen all the others equal to that one.

Sharpening The Depth Gauges

Now you have sharpened all the saw teeth, it is time to check the depth gauges.

You will notice that the top plate slopes down from the critical cutting point back to the rear. As you file the cutter, this clearance or slope becomes less and the chain will not “bite” as well as it should.

Periodical filing (i.e. this should not need doing every time you sharpen the saw) of the depth gauge will offset this gradual reduction. On average, depending on what type of wood you have been cutting, the depth gauges will need sharpening every 3 – 5 times you file the cutters.

The top plane chips at the wood in much the same action as that of a plane. The depth of the gauge from front to back determines how much wood will be taken off – if the depth is too shallow, not much will be taken off, but if it is too deep the saw will act very aggressively on the wood.

Set your gauge onto the chain and hold it with one hand. With the other hand, take your flat file and file until you reach the gauge. After you have completed filing the whole chain, it is best to saturate it in the recommended oil and check the tension before you use it again.

How Often Can I Sharpen My Chain?

Depending on the type of wood you are cutting, (i.e: soft wood, hard wood, frozen wood) your chain may need to be sharpened up to 5 times during the course of the day. It is highly recommended that you either replace or get your chain professionally ground after 5 hand filings.

Carrying the right tools is the secret to success when it comes to sharpening up. The job isn’t difficult, it just requires practice and a bit of skill. As you practice you’ll get the hang of it and find that you can get more out of your chains and string out the length of time between chain replacements or professional grindings.

What good is a dull chainsaw when it comes to clearing fallen trees after a hurricane? Or cutting timber to build yourself a shelter after a flood? With a little preparation and some practice, you’ll be able to keep your chainsaw in good condition so when disaster strikes, you’ll be ready.

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