Chainsaw blades don’t stretch. If it is too short, it won’t stretch. If it is too long, you can’t create enough tension on it. If the pitch is wrong, the motor sprocket will not engage, and if the gauge is too wide, it won’t slide into your bar.
Replacement chains and bars must have the proper sizing for your specific tool. You can’t go with a one-size-fits-all approach.
An electric chainsaw will generally have a bar under 18 inches and they will be in a narrower gauge. A chainsaw with a more powerful motor can power the chain around a longer bar and will have a heavier gauge saw chain.
The same thing goes with chainsaw chains. They have the length, pitch, and gauge to match specific bars.
Now, if you are like me, you threw the user manual away a long time ago, and you don’t want to make 10 trips to the farm supply to play a guessing game with the sizing.
As the middle-schoolers, these days say: “I got you, fam.” Here’s how to get the length of your chainsaw and the other measurements you need to buy replacement pars.
Safety Note: Hey knuckleheads! Power tools are dangerous. Don’t try to measure your chainsaw while it is running. And, for safety, unplug the spark plug wire to prevent accidental starting. (Not that you can intentionally start your chainsaw, anyhow.)
How To Measure Your Bar For Chain Replacement
Where To Look For Chain Measurements
The fastest way to get the correct replacement chain size is to find the sizing information that is stamped into the chainsaw bar. Generally, the bar size will be stamped into the bar, near the back where it is mounted to the saw.
Depending on the saw, it may be hidden. You may need to do a little disassembly to get to this information (you’ll be doing that anyhow to measure the bar, or to replace the chain.)
Just loosen the two bolts on the right side of the chainsaw body that are holding the housing in place, and you can access the full blade and look for stamped measurements.
In the example above, we can read that you need a 3/8″ pitch chain in the .50 gauge with 60 drive links long. You can take that information and hop into any hardware store to grab a replacement chain.
(I also go into what each of those three items mean, below)
However, if you are looking for the sizing on a bar that isn’t stamped, or where the markings have been worn off, then read on.
Measuring Your Chainsaw Bar
If you are shopping for a replacement bar for your chainsaw, you need to know the length. We’re going to measure what is known as the “cutting length” or the “called length”.
This is the part of the bar that extends outside of the motor housing and is the effective length used during the physical cutting process.
This is an easy measurement. To determine the chainsaw bar size, simply take a tape measure to measure from the motor housing body, down the length of the bar to the tip of the bar.
Then, round up to the next even figure.
So if you are looking at a bar that is 18.25 inches long, you’ll round up to a 20-inch replacement bar.
You’ll notice that they only increase in even numbers, so it will go 14″, 16″, 18″, 20″, 22″ etc.
You can also get the true length measurement. To do this, remove the bar and lay it on a flat surface. Then you can use a measuring tape to measure the entire length of the chainsaw bar from one end to the other. No rounding is needed with this method.
Some sites say that new bars are as expensive as a new chainsaw. Unless you have a super cheap chainsaw, this is a bunch of baloney. I was talking to an Arborist at Truefast Tree Service and they go through multiple bars a year.
Measuring Your Chain Length
Measuring the chain is a tiny bit harder than measuring the bar since you will need three numbers:
The pitch is the “chain size”. To get the pitch, measure the distance of 3 rivets. Then, divide that result by 2.
So the rivets are those little round spots on the side of the chain. They are what hold the chain together. You’ll pick any three, and measure from the center of the first one to the center of the third one.
Take that result, and divide it by two.
Note: The most common chain saw pitches on the market is 3/8″ (.375″, although everyone says 3/8″ instead) or .325″. You are pretty much guaranteed to have one or the other.
You’ll need the thickness of the drive portion of the chain that sits down inside of the bar. The available thickness of the drive links are .043″, .050″, .058″, and .063″. The most common gauge is .050″.
Generally, manufacturers have configured the saws with the lightest gauge that is likely to hold together for the amount of power you are using.
Chain gauges — or the thickness — is a little more intimidating, but the old-timers have a pretty cool hack of using spare change to determine the width of the groove.
- A Quarter = .063 Gauge
- A Penny = .058 Gauge
- A Dime = .050 Gauge
(You non-American visitors will first need to visit America to get some of our awesome coinage. Or grab a pair of calipers and measure the thickness on the old drive chain.)
Take a flat screwdriver and clean out the chainsaw bar groove and then slip the coin in. You want the coin that will fit the most snugly but that doesn’t have to be forced.
Of course, the chain will often have the gauge stamped on it as well.
You can either go with the called bar length that you determined in the first step, or you can count drive links to get the overall length.
It’s not helpful to try to measure the length of the chain itself, since the chain pitch, will determine the number of drive links you are supposed to have.
The drive links are the little hooked teeth that slip down into the groove of the bar. Counting them is fast and every chain you buy will be marked with how many “DL” long it is (as well as the called bar length).
Chainsaw Blade Cutter Types
Ok, now that you have your measurements, let’s talk about the different blade shapes.
The blade shape determines how well the blade cuts, and can be customized for the type of work you are doing.
Here are the modern cutting teeth with a brief explanation of each:
This chain uses a strong, square-cornered kerf that aggressively for the most efficient cutting. Because of the aggressive nature of this blade, it is best for saws with plenty of power and for working with softwoods where it can split the wood fibers easily and make short work of the task. Due to the blade shape, these saws have a high risk of kickback.
There are several variations of the semi-chisel, with some being called the “chamfer chisel” and going by other proprietary names. Where the full chipper is shaped like the number “7”, the semi-chisel has slightly rounded edges. The goal of this shape is to provide a medium cutting kerf that is efficient, but that has less chance of kickback and will hold its sharp edge for longer. They also hold their sharpness in dirty conditions, making this blade the real workhorse.
The chipper chain is fully rounded and is shaped to look like a question mark. This makes them the lowest-kickback risk and well-suited for working in dirty wood. The downside is that it is a slower blade. True chipper chains are nearly impossible to find, your best bet is to find a
Will Any Bar Fit Any Chainsaw?
The brand of replacement bar depends on the location of the tensioner holes and the oiler hole. Generally, your best bet is to buy the proper replacement bar, but a few brands like Oregon have done a great job creating compatible bars that can be used on Husqvarna and Stihl chainsaws.
Additionally, you need to buy a bar length that will match your horsepower rating. Larger chainsaw bars or thicker gauge blades will require more power. Most electric chainsaws are typically smaller and have 12-16 inch blades.
I’ve seen the guy at our MFA store get it right, time after time. But he’s seen the most common saws and blades, and even though he likes to guess before he measures, he still takes the time to get the proper measurements.