There is an old loggers saying which goes along the lines of: If your chain is sharp the chainsaw does the work, if it isn’t you do. This pretty well sums up what happens if you allow your chain to get dull. Performance will be severely hampered and blunt cutting equipment can not only cause you extra work but also be hazardous as it increases the chances of kickback.
Modern chains used on homeowner saws are relatively inexpensive and some people might be tempted just to replace the chain or get it sharpened locally – but the costs can still add up. The good news is that provided you have the right equipment (which is reasonably inexpensive), sharpening your own chains is something which you can easily learn. It will also save you a great deal of money in the long run and keep your saw working at its optimum level.
With a bit of practice you’ll soon find it easy to sharpen up in about 10 minutes and once you’ve mastered the art your chain will be good for years. A slight note of caution is that sharpening a dull chain from normal use is relatively straightforward. On the other hand, if the chain has become dull because of damage caused by hitting dirt, rocks or other hard objects then you may need to get it sharpened professionally or alternatively invest in a replacement.
When to sharpen
If you ever find yourself having to push your saw into the wood the chain is not sharp. There are also other signs that it is time to sharpen up and looking at the waste which comes from your cuts is a good starting place.
If the waste is in the form of chips everything is fine. If it is dust then this is a sure sign that it is dull and that it’s time to get out those tools.
Brief description of a chainsaw chain
Before looking at what tools required and the techniques you will need to use to carry out this task, let’s look briefly at the construction of the chain.
As you can see from the diagram above, there are both left and right cutters which are effectively the cutting teeth. The left and right cutters alternate around the chain to keep the cutting straight. The depth gauge is a small shark’s fin shaped piece of metal which controls how deep the cutters can cut into the wood.
On the cutters there are semi-circular cutting edges and these have a specific diameter depending on the type of chain. These are sharpened using a round file (see next section).
The depth gauge tip is a fraction shorter than the top of the cutter and after the cutter has been sharpened several times they can become the same level. This will prevent the saw from cutting so the depth gauges need to be lowered to the right height using a flat file and file guide.
Finally the diagram shows the drive links, which attach the chain to the guide bar.
Tools Required - Chainsaw File Kit
If you don’t already possess the necessary tools you will need to invest in a chainsaw file kit. Some of the tools required were mentioned above and these include:
- Round file used to sharpen the cutting edges of the cutters. This needs to match the cutter’s diameter and the most popular sizes for homeowner saws are 5/32”, 3/16” and 7/32”.
WARNING: although they may look similar, don’t use a standard rattail file for the job as it’s tapered shape and coarse teeth will damage the cutters.
- A file guide (holder) which will keep the round file at the same depth ensuring consistency when filing each individual cutter.
- A flat file and gauge which will be used occasionally to reset the length of the depth gauges (shark fins).
- Chainsaw filing vise (optional). If you have a workbench and vice you probably won’t need this but it is useful for using in the field. Simply force it into a log and you have a ready-made vise which will hold the guide bar.
How to determine file size
As indicated above, you will need to ensure that you get the correct round file to match the chain you are sharpening. But how do you know which one is right?
You will need to know either the Id number or the pitch of the particular chain being sharpened. The table below will give you some guidance in this regard. So, for the chain shown above which has an Id number 72, a 7/32” round file would be used.
20, 21, 22, 95
16, 18, 26, 27, 72, 73, 75
If you are not sure of the chain’s id number, the pitch will give you an indication of the size of tool required. The table below gives a general indication of the size of file you will need.
5/32 or 7/32
You should always check the manufacturer’s recommendations for a particular chain as sometimes a different size tool to the specifications outlined above might be recommended.
How to sharpen a chainsaw with a file
Here are some tips about how to properly sharpen your chain.
1. Always wear gloves to carry out this task.
2. Make sure the brake is engaged to stop the chain moving.
3. Gently clamp the guide bar in a vice.
4. Place the file guide (holder) between the rivets on the chain ensuring that the arrows on the guide are pointing towards the front of the chain. Unlike that being used in the video, you will find that some guides are like the picture below.
5. Use steady even strokes to file the cutter as demonstrated in the video below.
6. After sharpening a couple of cutters release the brake and move the chain along. Then reset the brake and sharpen some more cutters.
7. After all the cutters on one side of the saw have been sharpened, turn the saw around so the cutters on the other side of the chain can be sharpened.
8. After the cutters have been sharpened move on the depth gauges. These are the shark fin shaped pieces of metal. Use the depth gauge tool and file to adjust the height of the gauges on the chain. Basically if these gauges come above the cutters, file them flush with a flat file. If these gauges are too high the saw won’t cut.
I hope you found this article useful. If you need to get hold of a file kit, some popular products are listed below.
4.0, 4.8, 5.5 mm
(5/32, 3/16, 7/32 Inch)
4.0, 4.8, 5.5 mm
(5/32, 3/16, 7/32 Inch)
4.8mm (3/16 Inch)
4.5mm (11/64 Inch)
Just one more thing............
You'd think that someone somewhere could come up with a self sharpening chainsaw. Well the good news is that they have. Check out our review of the Oregon CS1500 self-sharpening chainsaw.
You'll never have to worry about filing your cutting equipment ever again!