Understanding Chain Ident.

Over the last few chainsaw maintenance courses that I've run, it's become obvious that there is some confusion over how to identify a chain. So, if this is something that you're not entirely sure about, here's your chance to get it nailed. Read on for more information...

Perhaps the easiest way to find out how to identify the chain correctly is to have a look at the following table. We'll just stick to Oregon, Stihl and Husqvarna...

	Oregon	Stihl	Husqvarna
No. on drive link	ID #. Look up in filing table.	Chain gauge. Ignore for now.	ID #. Look up in filing table.
No. on depth gauge.	Depth gauge setting in thousandths of an inch.	Chain pitch. Look up in filing table.	N/A

For Oregon and Stihl chains you'll also need to compare the cutter profile with that described in the filing table - that way you'll ensure you are looking at the relevant chain information.

Take a look at this previous post if you need to convert between Stihl's terminology for cutter profiles and others... Name Your Chain

Makita DCS4301 Review: Catch It If You Can.

Chain catchers. Vitally important in improving the safety of your chainsaw should something unexpected happen to the chain whilst you're using it. Different manufacturers do not create their chain catchers equally - even among their own offerings. So let's find out how Makita score on the DCS4301 after the jump...

Chain catchers are extremely simple devices and designed to take the energy out of the chain should it snap or derail. They are, in essence, consumable items and need to be easy to replace should something happen. Many of the home-user / farm-user level of saws have the chain catcher moulded in to the side plate, and this saw is no different. Of course, what it means is that should your chain demolish the chain catcher, you'll need to replace the complete side plate, rather than just the catcher itself.

The worst saw in this respect is my Husqvarna 350 - the chain catcher is actually moulded in to the main body of the saw! Not great.

Once you move in to the professional range of saws, things change - but at this level it's not unusual for the catcher to be integral with the side plate. Of course, you can help minimise the risks of something untoward happening to your saw by ensuring the tension is kept correct and ensuring the chain is being lubricated.

Air Filters...

The air filter plays a critical role in the smooth running of your chainsaw, and it's important that you look after it properly. There are several different ways of going about cleaning the filter and several different styles and fitments for filters too, so let's take a slightly deeper look after the jump...

The filter has one clear, obvious function in life, and it should come as no surprise that it's to filter the air prevent debris from entering the carburettor.

In order to run, the engine needs a mixture of fuel and air, and with that in mind it's easy to see that a clogged air filter will upset this balance. During use the engine is sucking in air via the air filter, and along with the air is all the dust and dirt that you're throwing up whilst sawing - hence the need to filter the air.

With the air filter choked up with sawdust, there will be a lack of air in that fuel:air ratio and this will cause the machine to run rich.

Fortunately, cleaning the air filter is a simple affair, and it doesn't get much simpler than using a brush (a clean, unused paint brush is ideal) to swipe the dirt from the face of the filter. The idea is to gently brush the dirt off - not stab it further in to the mesh!

There are a couple of other ways to clean the air filter...

• Wash it in warm soapy water - remember to rinse it, otherwise you'll end up with a bubble machine next time you start the saw.


• Use an airline - you may need to split the filter in half in order to blow the dust off of the face (i.e. blow from the inside -> outside). Make sure that it's the type of filter designed to be split in half before trying it ;-)

There are many different styles of air filter in use, even with machines made by the same manufacturer, so you might find that you need to unscrew the filter, twist it to remove it or fiddle around with those annoying little plastic clips simply lift it off.

One things for sure - if the filter and surrounding area is pretty filthy then you'd be wise to use that brush to remove 95% of the dust before removing the filter. Once the filter is removed, you might consider putting a loosely scrunched up ball of tissue gently into the carb opening; this will prevent small children and furry animals from falling in to the carburettor whilst the filter is off. It's also quite a good way of preventing more dust from getting in to the carb.

That's about it, for now, with air filters - keep it clean and you'll be helping your engine to run at it's optimum.

Drive Sprocket (Part 2)...

In the previous post we looked at removal of the drive sprocket from a Stihl chainsaw, which uses an inboard clutch (which makes removal very simple).

In this post we'll take a look at the slightly more awkward procedure when dealing with machines fitted with an outboard clutch - in this example we'll be using my Husqvarna 350 chainsaw. Find out more, and watch the video, after the jump...

Those chainsaws that use an outboard clutch need to be tackled differently from those fitted with an inboard clutch. Husqvarna, Partner and the Stihl climbing saws all utilise outboard clutches.

The issue with these machines is that the clutch actually prevents you from removing the drive sprocket, and attempting to undo the clutch weights just turns the engine over (let alone the fact that it's threaded the 'wrong' way).

So, remove the drive sprocket from these machines is a bit more involved; here are the steps:

1. Remove the side plate, bar and chain.


2. Remove the engine cover to gain access to the spark plug.


3. Remove the spark plug and fit in a piston stop tool.


4. Knock the clutch weights off (remembering the thread is reversed).


5. With the weights off, the drive sprocket can be removed along with the roller bearing.

The following video, although based on the Husqvarna 350 chainsaw, should be relevant to all chainsaws fitted with an outboard clutch.

Clutches...

The clutch on a chainsaw is of a centrifugal type, so that as the engine spins the clutch weights move out and engage with the inside of the sprocket.

Although there is little maintenance to do to a clutch, read on after the jump to find out a little bit more about the different clutch types...

There are two basic clutch configurations in use:

• Inboard clutch.


• Outboard clutch.

The image to the right shows an example of an inboard clutch as used on Stihl machines, and by Poulan as well, I think - although that's a US-based make rather than UK (interestingly enough Poulan is owned by Husqvarna, who mainly use outboard clutches on their own machines!). This clutch configuration has one great advantage - it's extremely easy to remove / replace the sprocket should you need to.

Outboard clutches, as seen in the picture on the left, are commonly used in Husqvarna and Partner saws, and Stihl climbing saws. This type of clutch makes removal of the drive sprocket much more awkward, but assessing the state of the chain brake band is made much easier.

In the next few posts we'll take a look at the drive sprockets, before returning to check out the clutch weights.

Creating Tension In A Video...

As promised in an earlier post, I thought I would try and create a short video about tensioning the chain, and here it is... after the jump...

Hopefully the following video will put across in a few short minutes what I was trying to get across on my earlier post.

Please, remember to wear gloves when you're handling the chain; lift the nose of the bar up when you adjust the tension; and tighten up those side plate nuts before you run the saw up!

Chain Sharpening (Part 3)...

Continuing on our journey to achieving a sharp, effective chain, in this post we'll look at the depth gauges and find out one way of setting them. More after the jump...

The depth gauge at the front of the cutter fulfils an important function - to regulate how much timber is actually cut. For this reason, it's important to keep these set at the correct height relative to the cutting edge - left too high and you'll not get an efficient cut, too low and you'll try taking too much wood out in one pass.

Leaving the cutter too high will occur if you don't check and set it regularly - as you sharpen the cutting edge, the height of that edge is actually reducing, and that means that you'll not be cutting as much as you could do. So, with the depth gauge left too high, by not setting it...

• Inefficient cutting as you could be cutting deeper.


• Takes longer to carry out the task.

But that's just mildly irritating when compared to the potential disaster that could await you if you decide to file the depth gauges down to much, and therefore try to cut too much timber in one go. So, for filing the depth gauges too low...

• ...you'll be trying to cut too much wood.


• ...vibration from the chainsaw increases dramatically.


• ...the saw may appear to be less powerful as it tries to keep up with the cut.


• But, worst of all, you massively increase the chance of kickback.

The tolerances for the depth gauge are fairly small, and 25 thou (0.65mm) is not uncommon. To maintain this setting there are a number of devices available on the market, from Stihl, Husqvarna and Oregon et al.

We'll take a look at some of these later on, but for now we'll use the simplest Depth Gauge Tool.

This tool, shown in the picture, can be laid on top of the chain with the notch at one end allowing the depth gauge to poke up through. You will need to remember two things if it needs to be filed down:

1. You must only file depth gauges on the other side of the bar to you.


2. You shouldn't file the depth gauge with the tool in place, otherwise you will effectively be altering the measurements set by using this tool.

Whilst you might be able to see the depth gauge poking up through the tool, it's easier to use a straight edge to run over the notched end of the tool. If the depth gauge is too high then it will catch on your straight edge.

If your depth gauge tool is like the one shown in these images, you should leave the tool in place whilst you file... but lift the back end up first. This has two advantages: 1) it uncovers the depth gauge giving you access to file it, and 2) it protects the cutting edge that you just sharpened.

That's about it really, work around one side, checking and setting as appropriate before turning the saw around and doing the other side.

Chain Sharpening: Part 1...

Sharpening your chain is one of those necessary evils that we all have to do in order to keep the chainsaw cutting efficiently, a dull, worn cutter is just not effective at getting through the wood and it'll tire you out, making life harder.

So, for an easy life with your chainsaw it's worth learning the art of sharpening the chain - it'll save you having to take the chain to your local garden machinery centre to have it sharpened and that means saving you money. How's that then, this site is already making your like easier and saving you money.

In order to sharpen your chain though, there's a few things that you need to know first - find out more after the jump.

To maintain your chain at it's most efficient and effective, you need to know something about your chain to find out the following details...

• What file size you should use.
• What filing angle you should be using.
• What the depth gauge setting should be (you do remember that the depth gauge on the cutter regulates how much wood gets cut don't you?)

To do this you have to know how to identify your chain, then you can set about finding the information you need. Let's take a look at chain ident.

Chain Identification

If you click on the image at the top left of this post, you'll see that the chain has some numbers on it (this particular chain is made by Oregon - one of the largest producers of after-market equipment for chainsaws).

The numbers appear on both the drive link and the cutter - or more specifically the depth gauge on the cutter. These numbers give us some clues to the chains identity - but be warned... Oregon, Stihl and Husqvarna all mark their chains differently, the numbers may be in the same place but the meanings differ. So here's your simple guide around the murky world of chain identification.

Oregon

Looking at that image again we can see that on the drive link is the number '18' and on the depth gauge, '50' appears. With Oregon chains the number appearing on the drive link is an I.D. number that you can cross-reference with a filing table.

The image above shows an Oregon filing table, these are pretty easy to use and your first step is to take a look down the left hand side and find the row which relates to the number of your chain.

Our particular example shows a number '18' chain - look down the bottom of the table and you'll find a row marked '18H*'; that's ours. Reading across the row, we find the following information (L-R):

• File size: 5.5mm round file.
• Depth gauge setting: 1.2mm (or 50 thou').
• Filing angle(1): we would need to hold the file 10^o down, while...
• Sharpening angle: ...pulling it back 35^o to ensure the correct cutting angle.
• Side plate angle: 85^o. Forget about this for a moment - we'll deal with this in a later post.
• Cutter profile: this is the profile of our chain - notice Oregon don't call it a chisel, semi-chisel or chipper; this is also true of Stihl. All you need to be sure of is that the profile matches the chain you are holding (you are wearing gloves whilst you hold that chain aren't you?).

But what if you have a #21 or #22 chain? Looking down the left hand column shows that there are two rows with these I.D. numbers - and the information within those rows is different. So how do you choose which one is yours? Easy - look over at the right hand side at the profile pictures, compare it to your cutter profile and whichever one matches is your row.

Stihl

Stihl do things differently, and the numbers on the chain refer to different things compared to Oregon (and Husqvarna). It's not better or worse, just different.

The number on the drive link of a Stihl chain relates to the gauge of that chain and you'll see one of the following:

1, 3, 5, 6, 8, 0

These figures relate to the normal gauge sizes of:

1.1, 1.3, 1.5, 1.6, 1.8, 2.0mm

The number on the cutter shows the pitch of the chain and will be listed as:

325, 3/8 or 404

We can use this pitch information to find the data we need for sharpening the chain; just search for all the chains with your pitch and refer to the chain type. We'll cover this in more detail in another post, as Stihl refer to their chains as Rapid, Picco, Super, Micro and Standard.

Husqvarna

Husqvarna have made it very easy. Just take a look at the number on the drive link, look down the Husqvarna filing table for the same number and there you have it.

Simple.

Next post... we'll take a look at the naming convention used by different manufacturers for their chain.

Related Posts:

[HD VIDEO]: Sharpening The Chain