by THE SAW DOCTOR
The chainsaw season is upon us once more for those of us in the cooler areas of Australia.
What I regularly see this time of year with chainsaw chains is that chainsaw enthusiasts try to sharpen their chainsaw chains themselves but unfortunately miss out on the main fundamentals in sharpening a chain which end up with you being frustrated as the chain just doesn’t seem right when cutting. This is where I would like to shed some light on the subject and hopefully lead you in the right direction with a happier outcome for you after all your time that you have spent sharpening the chain.
When sharpening your chain using a file, it is important that the correct size file is used to maintain the correct hook angle and gullet shape on the tooth.
The recommended size files are:
Now that you have the correct size file, it’s time to sharpen the chainsaw chain. It is really important that you remove all of the wear. What’s wear? I hear you say.
Wear is where the chain has become blunt, you will be able to see the wear on the cutting edge as this is grey in colour. The reason for the grey colour is because the chrome has worn off. The chrome is a very thin covering over the top of the tooth, it’s the chrome on the tooth that actually does the cutting.
The below diagram: The area of the tooth that is black is the wear. All of this would have to be filed out to achieve a sharp cutting edge.
The orange and black area in the diagram is the amount of wear that is to be removed to obtain a sharp cutting edge.
The below diagram: The orange area in the diagram shows the amount of wear that was removed to obtain a sharp cutting edge.
The chrome on the tooth can be removed in a matter of seconds if it comes in contact with dirt as this is very abrasive. That’s why you should avoid cutting tree roots, logs with termites and used railway sleepers.
When you start sharpening the tooth, if it takes four strokes of the file to remove the wear you have to continue filing four strokes of the file on every tooth. If the teeth become uneven in length between the right and left hand cutter this will cause the chain to pull to one side when cutting and eventually cause excessive wear on the bar.
Now that you have finished sharpening the teeth it’s now time to check the height of the depth gauge. The job of the depth gauge determines how much the tooth bites into the timber when cutting.
If the depth gauge is too low this will cause the tooth to bite into the timber too severely causing the chain to bounce around which makes it harder to control the chainsaw and also increases the risk of the chainsaw kicking back and you could end up injuring yourself. If the depth gauge is too high this will give the tooth less tooth bite and the tooth will fail to cut into the timber making the chain produce a fine powdery saw dust.
Here’s a classic example of a depth gauge on the chainsaw chain tooth that has been over ground. As the depth gauge has been virtually ground off this is quiet dangerous as this increases the risk of the tooth biting severely causing the chainsaw to bounce off the timber kicking back towards the operator.
Place the depth gauge setting tool on top of the chainsaw tooth. You will notice the depth gauge is poking up through the top of the depth gauge. To lower the depth gauge simply file the depth gauge until it is flat with the setting gauge. Should you place the setting tooth on top of the chainsaw tooth and the depth gauge is not poking through the top of the setting tool, no further action will be required.
Once you have finished lowering the depth gauges relief file the back of the depth gauge as this will give clearance relief and stops the depth gauge dragging through the cut.
If you do not have a depth gauge setting tool, you can purchase one at any chainsaw retailer.
The cost of the tool is roughly around $10.00 it’s a small cost to pay for the benefits that you will get from it. I highly recommend you get one.
A correctly sharpened chain all hinges on two things and that is that all the wear on the tooth is removed and the depth gauge is at the correct height.
So next time your sharpening your chain...remember these two key ingredients for correctly sharpening your chain and you will be on a winner!!!
Until next time.....Happy cutting!!