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A Chainsaw Primer

December 11th, 2011 Leave a comment Go to comments
This entry is part 1 of 2 in the series Chainsaws
My old Stihl 032AV

R.I.P. - 1982 to 2011

A couple weeks ago, Mr. Murphy paid me a visit and I had to replace my beloved 29 year old Stihl 032AV chainsaw. Soon after I wrote about how awesome and reliable it was, a valve in the chain oil system cracked and the part wasn’t available for a saw that old. So I had to buy a new one.

What I realized during my research is that there is a lot of confusion about the basic components of a chainsaw and few places where someone can find comprehensive answers. There are some great sites with very comprehensive answers and where professionals share their experience with homeowners, but it would still help to have an grasp of the basics before wading into these arenas.

What gives me the right to talk about this? I consider myself an advanced amateur. I grew up in a time and a place where there were far fewer nanny state rules. I was given my first real gas powered chainsaw at 10 years old and, after watching my dad for a while was given the intensive safety training of, “Don’t kill yourself,” and turned loose on brush piles with a Homelite saw with a 12″ bar. Bu the time I was 13 I was given a new Stihl 032AV (pictured above) and turned loose on 75 acres of fields and woods to cut whatever the hell I wanted. As long as there were a few cords of firewood for winter, no one cared. I used to practice felling trees by driving sticks into the ground in a field where I wanted the tree to fall and trying to drive them into the ground by dropping the trunk on top of them. Since then I’ve felled hundreds of trees, cut many cords of firewood, and cleaned up after dozens of storms. For a summer I worked for the US Forest Service in the early 90’s and that’s where I actually learned about safety and technique. I didn’t get to run the saw, but I was on work crews with guys who really knew what they were doing. And I soaked in everything I could.

What I wear now.

Gone are the days of being an invincible kid with no safety gear at all. You will never catch me cutting now without my full compliment of chaps and forestry helmet (hard hat with built in face shield and ear protection).

So, based on that experience, here’s what you need to know.

Types of Chainsaws

Manufacturers usually divide their chainsaw lines into three categories. Known by various names, I will call them: Homeowner or Occasional Use saws; Medium Duty saws; and Professional or Heavy Duty saws. In general, as you move up from Homeowner to Professional saws you get larger sizes (both bar length and engine displacement), more power, and more advanced features (like high efficiency engines and anti-vibration features).

I am partial to Stihl chainsaws, for no reason other than I have always lived near quality Stihl dealers. So I’ll use their line as an example.

A middle of the pack Occasional Use saw might be the MS 211. Offering a 2.2 in3 engine that produces 2.3 horsepower, Stihl recommends guide bars in 12″, 14″, or 16″ length. Other than some new engine technology Stihl is introducing, there are no special features to this saw, though some Homeowner saws have “convenience” features like easy start systems. Saws in this class would typically be used for cutting small trees (up to maybe 16″ in diameter), large branches and pruning ornamental plants, and light cutting of firewood.

Old and new chainsaws.

Out with the old and in with the new. My new MS290 and my old 032AV

A Medium Use saw is the MS 290 (my most recent saw). The 290 has a 3.45 in3 engine making 3.8 horsepower (65% more than the MS211). Stihl recommends guidebars in 16″, 18″, and 20″ lengths. In addition to the basic features, medium range saws offer adjustable chain oil rates, anti-vibration systems (which help reduce fatigue when using the saw for hours at a time), and easy access maintenance features. Medium use saws might be used for felling trees up to 36″ in diameter, limbing large trees, and bucking (cutting into smaller lengths) trees for firewood.

A Professional saw is the Stihl MS460. With a 4.6 in3 engine making 6.0 horsepower (58% more than the MS290). For this saw, Stihl recommends guidebars in 18″, 20″, 22″, or 28″ lengths. Saws in this range get the latest features to make them light and powerful. This saw might be used for felling trees to 48″ in diameter and bucking large trees. The largest Professional saw in Stihl’s line, the MS880 Magnum can take a guidebar up to 59″, for felling trees 6, 7, 8, or even 10 feet in diameter.

What Size Saw Do You Need?

Because chainsaws tend to be tools for men, there is a perception that bigger is always better. That perception is commonly held by people who have watched too many episodes of Ax Men on TV and have never spent a day bent over cutting firewood with a 20 lb. chainsaw.

Chainsaws can be dangerous, and a bigger saw can let you get into dangerous situations faster than you might expect. So it is important to match the saw to the job you will actually be doing. For example – even when I fell a 30″ diameter tree, that whole process might take 120 seconds of actual cutting. But the next two hours will be spent limbing and bucking that tree into firewood. So as nice as an MS880 Magnum would be during the felling process, my back is much happier limbing with my MS290 for the next two hours because it weighs ten pounds less.

You need to realistically assess the size jobs you will really do. Will you really be felling three or four foot diameter trees? That can be difficult and dangerous work and it’s way too easy to drop a tree on your home or car if you don’t know what you’re doing. Want proof? See this video:

Or this one:

Or this one:

Remember – each of these guys thought they were smart enough to handle the job. Although lack of safety equipment, no felling wedges, or no notch and back cuts is usually a dead giveaway that someone doesn’t have a clue.

Here’s your first pro tip – the saw binding in your felling cut is nature’s way of telling you something is screwed up and the tree isn’t going the way you expect. This is why they invented the felling wedge.

Here’s your second pro tip – if you don’t know what a felling wedge is, stick with an Occasional Use or smaller Medium Duty saw.

If you want to know and see how they are used properly, this guy on YouTube gives a great lesson in cutting a tree that’s leaning in the wrong direction and safely directing it where he wants it using wedges. When you can do cuts like this, you’re ready for a large saw and larger trees.

Chainsaw Parts

To many people, this whole system is a “chainsaw.”

In fact, a chainsaw is made up of several components, and it is common to mix components from a variety of manufacturers. The basic anatomy of a chainsaw is:

  • The engine or powerhead. This consists of the engine and related controls, the oiling system, and related components.
  • The guidebar. This is the bar on the front of the powerhead around which the chain runs.
  • The cutting chain. Exactly what the name says. This is the chain that does the cutting.
Information block stamped on guidebar.

Information about the proper chain to use is on the guidebar, not the powerhead. Here's the block on my Stihl MS290.

On all but the cheapest Occasional Use saws, you can buy chain and guidebar systems from a different manufacturer than made the powerhead. For example, many Stihl chainsaw owners use guidebars and chain made by the Oregon company.
Here’s the important thing to know: the chain on a chainsaw must be matched to the guidebar, not to the powerhead model. And the drive sprocket must be matched to the chain as well. So there really is no answer to the question, “What chain do I run on a Stihl MS290?” The answer is, it depends on what bar you have. The picture on the right shows the information from my MS290. It tells me I should run a .325″ pitch chain, .063″ gauge, with 74 drive links on this 18″ bar.

Guidebar Types

In America, there are really only two guidebar manufacturers. Stihl and Oregon. Any brand of chainsaw other than Stihl uses Oregon manufactured bars, even if their own brand name is on it. And regardless of which manufacturer you use, there are two broad categories of guidebars, regular and reduced kickback.

Kickback is the rapid and unexpected movement of a chainsaw towards the operator caused when the chain on the top of the guidebar sticks in a cut or contacts something in a dangerous and unexpected way. If this happens at the tip of the bar, the movement of the saw and running chain is both back toward the operator and up towards the operator’s head. This is perhaps the most dangerous type of chainsaw accident and a very common occurrence. A good demonstration by a chainsaw instructor is in this video:

A common way for kickback to occur is during plunge cutting (when the tip of the guidebar is pushed straight into a cut, rather than a slicing cut made with the top or bottom of the guidebar). To lessen this, reduced kickback guidebars tend to be fatter in the middle and tapered towards their ends. Compare the Stihl Rollomatic E reduced kickback bar against the Duromatic E standard bar on this page for an example. Note that in the picture, the Rollomatic bars have a green dot at the end and the Duramatic bars have a yellow dot. Stihl uses this color coding system to designate bars and chain as reduced kickback (green dot) or regular (yellow dot). Oregon uses blue dots for reduced kickback and yellow for regular.

I have run reduced kickback bars on my saws for years and never missed my old straight bars once. In my mind, there really isn’t a decision to be made here. If you’re reading this you should be running a reduced kickback bar.


The next discussion is about chain types. But this discussion among chainsaw people is like asking someone what beer is the best or which football team to root for. There is a lot of fighting and arguing that takes place, so I intend to cover this in a second post. Keep an eye out.

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  1. Rick
    December 6th, 2013 at 07:47 | #1

    Great post. I’d love to cut with you and learn. I also had an .032 – which I loved. Mine started every time w/ few pulls. Do you know which new model comes closest to replacing it in quality and durability?

  1. November 1st, 2012 at 20:19 | #1