using a file to sharpen chainsaw

How to Sharpen a Chainsaw Step by Step Guide

sharpening a chainsawA chainsaw is an indispensable tool for any home handyperson, because of their flexibility and portability.

A well maintained, sharp chainsaw should be able to cut through any wood with very little effort.

And there is the rub of course, as I’d say the majority of chainsaw owners either never sharpen their chainsaw, or don’t sharpen it nearly enough. The good news is that there is no reason to put this off any longer.

Using a chainsaw sharpener is very easy, in fact well within the reach of any chainsaw owner.

In fact, depending on how technical you want to get you can sharpen a chainsaw without even needing a dedicated chainsaw sharpener!

For many professionals a small round file is all that is carried for day to day chain sharpening.

When to Sharpen?

Here’s a few clues to look out for that will tell you it is time to sharpen your chainsaw:

When it is difficult to cut with the saw – this one is pretty obvious. A sharp chain blade should not require a lot of pressure to cut through the wood. If you are using a lot of effort pushing down on the saw to cut with it, it’s time to sharpen the blade.

You are producing fine sawdust when cutting – a sharp blade should produce regular, square-ish wood chips. If your saw is making a finer dust, it may be blunt.

Sharpening your chainsaw with a file is made easier by the use of a file guide or file holder, which is a simple guide that positions your file at the correct angle and allows you to sharpen the chainsaw teeth at a uniform angle. These are not strictly necessary but are a great idea if you are new to the procedure.

How to Sharpen a Chainsawusing a file to sharpen chainsaw

To sharpen your chainsaw, first of all you will want to clamp the chain bar in a bench top vise in such a way that the chain can spin freely. If necessary, use an off cut of wood to support the body of your chainsaw.

If you are working in the field a pin vise may be useful – this is a portable vise that can be set into a stump of wood and hold the blade while it is being sharpened.

Tightening the chain in advance will make it easier to sharpen each tooth, as they will be less likely to move while being sharpened.

You should start at one tooth and rotate the blade as you sharpen each tooth until you have done the whole chain. It’s not a bad idea to put a small pen or pencil mark on the tooth that you start on so that you know when to stop.

Now you are ready to use your small round file of the correct diameter (with or without a file guide) to sharpen each tooth of the chainsaw.

There are several cutting surfaces to pay attention to on the chain blade, with teeth designed to work the cut on both sides of the blade.

You will find it useful to sharpen all of the teeth facing in one direction, and then rotate the chainsaw in your vise before sharpening those on the other side. To sharpen each tooth, draw your file across the cutting surface at the same angle as already exists on the tooth.

When you are filing with a round file, hold about 20% of the height of the file above the top of the cutting tooth to help maintain the correct shape of the cutting surface (see diagram below).

Two to three strokes should be enough to restore an edge to a tooth that has been lightly worn. If the tooth is more heavily worn, more strokes may be required – try to remember how many strokes are required so that you can sharpen consistently.

If using a file guide for sharpening, check your chainsaw manual to find the correct angle for each tooth.

If your manual has gone walking a rule of thumb is a 25 degree angle for each cutting tooth, but different models do vary.

Even among those who sharpen their own chain blades regularly, depth gauges are sometimes overlooked. Maintaining your depth gauges is very important to cut safely and effectively.

An alternative to using a file is to use a circular electric chainsaw sharpener – these can be dedicated sharpeners or bits designed to fit into a drill or similar.

Finally, although sharpening your chainsaw with a file or electric chainsaw sharpener will help keep an edge, it is still advisable to have the chain blade sharpened regularly by a professional, who will be able to ensure that each tooth is at the correct cutting angle.

sharpening your chainsaw regularly is an important part of your chainsaw maintenance program. However many chainsaw owners overlook the step of adjusting the depth gauges on the chainsaw chain at the same time as sharpening the teeth.

In fact, just last week I was talking to my father in law about how I was starting a site about chainsaw sharpeners and we got into a conversation about it. Turns out, although he has a property and sharpens his own chainsaw, he didn’t even know what a depth gauge was!

Chainsaw depth gauge

The role of the depth gauge is to control the thickness of the chip that is removed by the cutting tooth, which follows behind it. As you can see in the diagram, the chain gauge should be a little below the top of the cutting tooth. This distance is quite small, so a specialized tool is used to get the correct distance.

Check your chainsaw manual to find out what your cutting depth should be set to. chainsaw depth gauge

As a rule of thumb, check the depth gauges every second or third time you sharpen your chainsaw and adjust them at the same time if necessary.

The depth gauge is adjusted by holding the depth gauge tool over the depth tooth, and filing straight across the top of the tooth with a flat file until the tooth does not protrude from the notch in the tool.

Filing the depth gauge tooth will naturally mean that the tooth loses it’s rounded shape. You can use a saw chain tool to measure the height. Once the height is correct, restore the rounded shape using your file.

This will stop the tooth from sticking in the cut as you use the chainsaw.

As with the tooth sharpening procedure, rotate the chain around the chain bar and adjust all of the depth teeth equally before you use the chainsaw.

About the Author Bill

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