Blast From The Past

Just before Xmas a friend of mine turned up at DriveLink HQ with this saw - cheers Glenn! It's an old Stihl 08 and we thought it might be worth cleaning it up and checking it out - not that we're going to use it as by today's standards this thing is seen as unsafe. Find out more after the jump...

I've not actually had a chance to look over it yet, I just popped it on top of some logs to take the picture above, but one thing is for sure... it's lacking in what we would consider to be modern safety features! There's no chain brake for starters. There's no AV mounts (at least none that are immediately obvious - perhaps I'll find some once I start disassembling it). And it weighs a ton compared to modern saws, being built entirely out of metal. Oh, there's also no safety throttle, and you can put the saw to full power and then lock it in that position.

I'll post back about this saw occasionally, let you know what I find and if it's worth restoring / repairing it then we'll do that and you can up-to-date with the proceedings.

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

Give Me A Hand...

How much attention do you give your personal protective equipment? Do you just throw it in the back of the wagon once you've finished the job? How do you dry out your gear once it's been soaked in the latest summer downpour? In this post, I'll take a look at chainsaw gloves - and hopefully they don't look like the pair in the photo. Find out more after the jump...

As you can guess from the picture at the top, these chainsaw gloves were not in a condition to provide any protection - if you're gloves look like that, do yourself a favour and replace them. New chainsaw gloves are not really that cheap - not like a pair of work gloves at £1.99, and so you should look after them. But how?

Ever read those little paper booklets that come with new gloves / jackets / helmets / boots / etc.? Stihl recently sent us a new pair of gloves and I thought I'd take a moment to browse through the leaflet and report my findings.

During the course of normal tree work, chainsaw gloves live a hard life, dragging brash, using a chainsaw, winching and so on. They get pretty grubby, pretty quickly and if they then get wet as well they'll set rock hard - making them difficult to put on and uncomfortable to wear. Improper care will also accelerate the demise of the stitching caused by fuel, oil and maybe stump protection fluids - all things that are not recommended to come in to contact with the gloves.

I've never read the leaflet that comes with gloves and I'm as guilty as the next person of just abusing them until they fall apart and then getting another pair - but what I found was interesting. For instance, were you aware that you can wash those gloves? I wasn't, but it turns out that these Stihl gloves can be washed gently in warm, soapy water when they get dirty. Or contaminated with petrol. Or oil. Or indeed, anything else. Of course, they need to be dried, in just the same way they should be if they get thoroughly soaked during inclement weather.

Drying gloves should be done without unnatural sources of heat, i.e. don't go putting them directly on a radiator, or use a hairdryer to drive off the moisture. Put them somewhere where they can dry out slowly over time and once dry, they should be treated with a leather feed - I'm thinking something like NikWax should do.

So, it seems that looking after your gloves might just save you some money - but there's obviously a 'fiddle-factor' involved in maintaining them. Having said that, I've got an oldish pair of Husqvarna gloves that could do with a good clean, I might just try it and see what happens...

Stihl Quick Tension System...

Maintaining the correct chain tension is rather important - too loose and the chain may derail, too tight and the saw will effectively lose power. Many saws require the operator to carry around a combi-spanner to adjust the tension, but a number of smaller saws are available fitted with a quick tension system. In this article, we'll have a look at them and see how they compare after the jump...

I mentioned above a couple of issues regarding chain tension, but there's more; a chain that's too loose will also not cut as effectively as a correctly tensioned chain. Why? Because as the cutters come in to contact with the wood they sit back slightly, and that results in the cutting angles changing. A loose chain will also wear quicker, as well as increasing the wear on the guide bar. Fortunately you can easily recognise a loose chain - either because it's hanging down from the underside of the bar, or because it revolves around the bar when the engine is at tickover (with idle speed adjusted correctly).

A chain that's too tight will result in the chainsaw using up some of it's power to overcome the friction and that's what results in the lack of apparent power and unwillingness to rev freely. That increase in friction can lead to overheating too. It also puts the bearings of the nose sprocket and drive sprocket under undue stress.

So, convinced of the need to get the correct tension, the easiest and fastest method would seem appropriate; but different saws use different systems. The standard method, shown on the right, uses an adjuster screw that can be accessed through the side panel (although some saws have the adjuster screw at the front, facing forward, next to the guide bar - these are really awkward to use, especially with a combi-spanner). Before we can set the tension, those two nuts holding the panel in place must be loosened first as they're also clamping the bar in position.

Maintaining the tension in this manner requires the user to carry around a combi-spanner (with a flat end, not a Torx-head end). The operator first loosens off the two nuts, sets the tension using the flat screwdriver, and then tightens up the two nuts. Job done.

Nowadays, many users (particularly home-users) don't want the aggravation of having to have the combi-spanner to hand in order to adjust the chain, and manufacturers set about finding an even quicker way of correcting the chain tension with the least amount of fiddling about.

Enter stage left... the quick tension system. The example in the photo here is off of a Stihl MS250C, but it's similar to many other fast tensioners. The photo at the top of the post shows it with the side panel still fitted. You can see on that photo the large 'dial' on the side - this is not the tensioner, but it's a quick release for the side panel. The actual bit that the operator uses is on the top of the side panel - a small black wheel that links in to the cog fitted to the guide bar (that can be seen on the photo to the left).

To adjust this system, all you need do is flick the handle out of the quick release dial, back it off a fraction, then use the adjustment wheel to set the tension and tighten up on the side panel. It is quick and it doesn't require any tools. But is it any good?

Personally, I found it a bit awkward to get the right tension and it's not as finely adjustable as the good old screwdriver adjuster. Having said that, it does work, but I'm not sure I'd want one on a professional saw; for the home- / occasional- user however it's probably ideal. It also means that changing the guide bar is not quite as quick either, as that big cog is bolted to it and should be removed before swapping bars - the other thing that it means is that when it comes to your regular servicing and you turn the bar over to even out wear... you need to take the cog off and swap it over too.

So, for now at least, it's the old way of doing things that wins it for me; not just for setting the tension but also for ease of maintenance.

EasyStart Systems...

Most of the major chainsaw manufacturers now offer an EasyStart system, designed to make using the recoil starter much easier to use when starting the saw. Stihl have their ErgoStart™ system and Makita have their Featherlight-Start™ system. These are often found on saws dedicated for home-users and 'light-use' saws, with the professional models making do with decompression switches instead. Find out more about these systems after the jump...

When teaching chainsaw maintenance and crosscutting I've found that many women have difficulty in starting chainsaws; for that reason we purchased a Stihl MS250C which is fitted with an ErgoStart recoil starter.

This uses a some trickery with smoke and mirrors springs to assist the user when starting the saw; and I have to say that it really works. The saw is so simple to start that a child could start it - although I'm not too sure why you'd want a kid to start a chainsaw, but you get the point. In fact, before we broke it when out on a felling course, this was a firm favourite amongst all the students (and I often used it for demonstrations).

As well as Stihl, Makita also offer their Feather-Light Start system that is very similar to Stihl's ErgoStart and is equally effective in making the chainsaw that much easier to get going.

So, are there any disadvantages? With the Stihl saws, there is a noticeable increase in the size of the recoil starter housing, which is just not apparent on the Makita system. The maintenance of the recoil starter is a little bit more awkward with these easy-start systems, but it's not too taxing.

The only real issue is that these systems do not seem to have found their way on to the professional saws - these tend to utilise decompression valves instead. However, for non-professional users or those using a saw only intermittently, choosing a saw with an easy start does improve the ease of ownership and they're well worth checking out.

Recoil Starters...

The recoil starter is something that requires little in the way of maintenance; but it's worth taking care of it, if it's not to fail just when you need it, i.e. when you start the saw. Let's take a look at it after the jump...

There are a couple of different types of recoil starter on the market, from the most basic setup through to slightly more complicated systems such as the Stihl ErgoStart™ - which really does make starting a chainsaw very easy.

The basic principle is that as you pull on the cord, a pulley turns which will cause a flywheel to turn. This is the really nifty bit - as the flywheel turns the engine will also go round, but it also generates a little bit of electricity to send to the spark plug. With the engine turning and drawing in fuel, and the spark plug generating a spark, everything is set to run.

But how does it engage the flywheel when you pull and then automatically disengage when the engine runs? The recoil starter uses a small pawl which is thrown out when you pull on the cord, but is pushed back by the flywheel when the engine turns. It's really very simple, and there's not a lot to go wrong.

The main thing is that eventually the starter cord will break as it wears through use - normally this is at one end (near the handle, or near the pulley) and you can often see the cord fraying at these points. It's a good idea to carry around a spare starter cord when you're out using the chainsaw.

Replacing the starter cord is not too difficult (if you've got the basic system) and the following video shows you how to replace the starter cord on a Stihl chainsaw.

Setting the tension is important - too much tension and you risk damaging the spring or other components, and you won't be able to achieve the full 'pull-length' as the cord will bind before it reaches it's maximum length; on the other hand, have the tension too loose and the handle will not retract properly.

Fortunately it's quite easy to check for the correct tension; after retensioning, hold the handle down against the starter housing - it should return to the upright position and stay there. If it doesn't fully return to the starting position then there's not enough tension in the spring. To check that it's not too tight, pull the handle out as far as you can, then (and this is where you need three hands), keep it at full stretch and try to turn the pulley - it should be possible to tighten it about a ¼ of a turn.

That's about it really. Just keep an eye on the cord wear, and carry and spare around if you're out doing tree work.

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.

Drive Sprocket (Part 1)...

The drive sprocket is all-important in transferring the drive from the engine to your chain, and it's another consumable item that's under a lot of stress from various elements.

In this post we'll take a look at removing one common type of drive sprocket that you'd find in a Stihl chainsaw. Find out more after the jump...

Removing the sprocket on a machine such a Stihl ground saw, is a very simple process and certainly much easier than a Husqvarna (or a Stihl climbing saw for that matter) - as you may have already seen from the video in the last post.

The reason that it's so simple is due to the method of clutch drive chosen - in these saws the clutch is fitted in the main engine housing and is known as an inboard clutch. With this type of clutch, the drive sprocket can be removed just by taking off a circlip.

It's really that simple - but let's just go through the steps one-by-one:

1. Remove the side plate, bar and chain (make sure you wear gloves when handling the chain).


2. Make sure the chain brake is off (handle pulled back). If the chain brake is left on, you will not be able to remove the sprocket as the brake operates directly on the drive sprocket.


3. Remove the circlip holding the drive sprocket in place.


4. Withdraw the sprocket, it should come out easily, but if you haven't cleaned your saw for a considerable period then it may be nigh on impossible more difficult.


5. You should be able to see a [needle-roller] bearing. This will either be left on the end of the crankshaft or will have come off with the sprocket... either way, don't loose it!

The image below shows this in pictorial form, click on it to get the larger image (it's around 1Mb).

With the drive sprocket removed, you can now assess the wear on it - if you've been using it for a while then you'll probably notice scoring and general wear and tear pretty easily.

In our next post, we'll take a look at how to remove the drive sprocket from a chainsaw such as a Husqvarna, as they use a different method. After that, we'll take a closer look at that wear and how to decide when you need a new sprocket.

Replacing Stihl's Drive Sprocket

I thought I should even up the scores a bit - after doing a short video on taking out a Husqvarna drive sprocket, I thought I should create one for Stihl saws (although due to my own ineptitude you'll see the Husqvarna video in the next post). Watch the video after the jump...

As I mentioned in an earlier post, removal of the drive sprocket from a Stihl ground saw (or indeed most ground saws with an inboard clutch), is particularly easy; and that makes for easier maintenance. So the following video, based on a Stihl MS260, should be relevant for most saws having the same clutch setup. It's about 3mins 30sec long and represents my most advanced video to date! (Although the YouTube quality leaves a little to be desired - I just wish I could show the full MPEG-2 video CD.

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