Lightweight chainsaw chains and bars under the name “Narrow Kerf” (NK) have gained popularity in the chainsaw market in the past two decades, and have been universal adopted by chainsaw manufacturers for the low-power end of the chainsaw range.
The narrow kerf bars and chains promise faster cutting and lower weight, but are also a source of much confusion: the narrow kerf sizes are brand-specific and, due to the model naming protocol, all too easy to mix with the regular kerf counterparts.
In this article, I explain what narrow kerf chains are about and what sizes/types you have to choose from. In a nutshell, narrow kerf chainsaw chains are chains with a slim cutter profile designed to make a narrower-than-usual cut into the wood. The reduced cut width saves power and improves the performance of low-powered chainsaws. The narrow kerf sizes also allow for lighter bar–chain combinations and improve working ergonomy.
Below, we will go through this in more detail, starting with what are narrow kerf chains and bars, how to identify them, and all the 10 or so sizes. We will then look at which saws narrow kerf is, or could be, used for and try to put some numbers to the speed and weight advantage.
What is Narrow Kerf (NK)?
“Narrow kerf” is a family of chainsaw chain sizes with narrow-profile cutters (i.e. teeth). These chains are intended to be both lighter to run and lighter in weight, giving performance and ergonomic advantage when used in light, low-powered saws.
Each of the big manufacturers Husqvarna, Oregon and Stihl have introduced their own narrow kerf sizes. The sizes are differentiated from the regular chain sizes by (brand-specific) designations like Pixel, Speedcut and Picco. Some narrow kerf sizes are also available from Carlton and Windsor.
The big thing to note here is that the narrow kerf chain sizes are proprietary and not completely cross-compatible.
What is a Narrow Kerf bar?
Most narrow kerf chains should be run on a matched narrow kerf guide bar. The narrow kerf bars are simply guide bars in the narrow kerf chain pitches and gauges that are thinner than regular bars.
As an example, I measured a thickness of .15” for an Oregon 3/8” low profile narrow kerf bar, while a regular-kerf 3/8” bar (Stihl Rollomatic E) was around .18”.
The reduced thickness ensures clearance in the narrower cut and also helps to reduce weight. The downside is that the narrow kerf bars are more flexible and more easily bent. For this reason, they are also not available longer than 20”.
Narrow kerf bars are available from Oregon, Stihl, Husqvarna and Sugihara.
Narrow Kerf chain sizes
Narrow kerf chains and bars come in around 10 sizes or formats. Like other chainsaw chain sizes, the narrow kerf sizes are coded through chain pitch and gauge. In general, narrow kerf chains come in pitches 1/4”, .325” and 3/8” and gauges .043” and .050”.
Some pitch&gauge combinations come in both narrow and regular kerf. To avoid confusion, manufacturers designate the narrow kerf versions with brand-specific product names or specifiers to the pitch. These narrow-kerf identifiers for the leading brands are:
- Husqvarna: Pixel, Mini and Mini Pixel (before/after pitch)
- Oregon: Speedcut and Speedcut Nano (product lines)
- Stihl: Picco and Picco Micro Mini (after pitch)
The table below shows a summary of the narrow kerf bar and chain loop sizes available from the three manufacturers.
BARS & CHAINS
|Husqvarna||.325” Mini Pixel||.043”||12”…16”|
|3/8” Mini Pixel||.043”||12”…14”|
|Speedcut Nano |
Narrow kerf vs. Low profile
A term related to (and often mixed with) narrow kerf is Low Profile (LP) . How are the two terms related?
After studying the topic for a while, I came to the conclusion that low profile in chainsaw chains is often used with the same chains as narrow kerf: chains with narrower and shorter cutters than regular.
There is a difference in meaning, though: while narrow kerf is used to refer to the whole group, low profile is used specifically of the narrow kerf chains with pitches .325” and 3/8” to differentiate them from the regular-kerf versions.
Thus, you will see Stihl Picco denoted as 3/8” Low Profile, sometimes abbreviated 3/8”LP, to tell it apart from regular 3/8” chains. But you would not see the Picco Micro Mini (PMM) written as 1/4” Low Profile – the 1/4” is a narrow kerf pitch and there is no regular kerf 1/4” to differentiate the PMM from.
Which chainsaws are narrow kerf?
All battery chainsaws, most electric saws and most gasoline-powered saws under 50cc from the major brands come with a narrow kerf bar and chain as the stock option.
Popular saws from Husqvarna and Stihl with narrow kerf as standard are: Stihl MS 170 and rest of the MS 100-series, MSE electric models (except MSE 250), and MSA; Husqvarna 100 series, 400- and 500-series below 450 and 543, and battery models.
The model ranges are listed in the table below in more detail; for a more exhaustive list, see my articles on Husqvarna and Stihl bar sizes.
|Stihl||MS 150…194, 201…211|
Converting to Narrow kerf
Many bigger or older saws can also be converted to run a narrow kerf chain. To go narrow kerf, you must replace the bar with a narrow kerf bar and usually also swap the drive sprocket to match the narrow kerf pitch. (The drive sprocket is the spur wheel on the right hand side of the saw powerhead that runs the chain.)
NB. The regular 3/8” drive sprockets cannot run 3/8” low profile (Picco) chains. That is, the narrow kerf chains are usually incompatible with regular drive sprockets and bars despite the same nominal pitch.
The table below lists the saw power ranges that Husqvarna, Oregon and Stihl either recommend or stock narrow kerf for. When planning to convert to narrow kerf, use the table to check which narrow kerf size would be a good match to your powerhead.
|Chain type||Saw power |
|Husqvarna||Pixel 3/8” Mini||(battery)|
|Pixel .325”||2.2…3.4 hp|
|3/8” Mini||1.5…2.4 hp|
|Stihl||3/8” Picco||2.0…2.5 hp |
|3/8” Picco Super 3||<2.0 hp (1.5 kW)|
|<2.0 hp (1.5 kW)|
How much faster is Narrow Kerf?
Although hard data is difficult to come by, a narrow kerf chain can be expected to do cross-cuts around 10% faster than a regular chain with the same saw power.
Narrow kerf chain manufacturers present the advantages of these chains mainly in qualitative terms. I was not able to find any numbers from Husqvarna or Stihl, but Oregon gives “15% higher efficiency” for SpeedCut Nano.
The user reports I found support the +10% speed increase range. I have not yet been able to verify this personally, since I do not have regular and narrow kerf saws with similar enough power.
In ripping cuts, I would expect the narrow kerf advantage to be substantially higher, the reason being that in ripping the cutting effort is more directly proportional to the cut width.
How much lighter is Narrow kerf?
Light weight is one of the key selling points of narrow kerf, but how much lighter is it really?
I weighed a few chain&bar combinations and found that with 15” bars a 3/8” low profile narrow kerf option was a full 30% lighter than a regular 3/8” Stihl Rollomatic. This is quite well in line with Oregon, which promises 20% lower weight for their SpeedCut narrow kerf guide bars.
The 20%…30% means an absolute weight difference of only ~ 1 lb. for an 18” bar. However, it improves handling proportionally more since the weight is off the bar which extends out of the saw body. As a result, a saw with a narrow kerf bar is noticeably easier to balance than one with a regular kerf bar, particularly with the longer 18” and 20” bars.
Narrow kerf ripping chains?
Chainsaw milling is one of the heavier chainsaw applications and most ripping chains are regular kerf. However, there is a narrow kerf ripping chain in the 3/8” low profile format available from Granberg – see my article on ripping chains for more info.
Narrow kerf should in fact give even more advantage over regular kerf in ripping cuts, i.e. cuts along the wood grain. The reason is that these cuts involve cutting wood fiber over the whole kerf width.
In cross-cuts, i.e. cuts across the wood grain, which constitute probably 99% of chainsaw use, wood fiber is cut only on the cut side faces. These faces are actually the same for both regular and narrow kerf. Here the narrow kerf advantage is that it needs to do less of the planing-type cutting between the wood fibers.