December 05, 2022
I’ve used chainsaws around the farm and in our land management efforts for years. Yet, when it came to the moment of a dull saw chain, it always seemed more convenient to make a quick run to the local Farm & Home mechanic than to take the time to learn how to do it on my own. That all changed recently when I decided to increase my masculinity meter, so that my buddies didn’t mistake me for a pipsqueak salesman from the city instead of the farm-raised Missouri bowhunter that I am.
I took the time to do some research, locate the proper tools and did what every millennial does these days, watched several YouTube videos. What I took away is that the saw chain sharpening process really boils down to four main processes or steps … identifying chain type, assessing your chain to determine how to file, filing your cutters and filing the depth gauges. Yep … that’s it. Of course, there are intricacies of sorts but as you will find out here, you will spend more time learning the parts of your chain than you will performing the process.
Before sharpening, we need to address the two must-haves’ in being prepared to sharpen your chain. First, it is very helpful to understand the parts of your saw chain. Second, having the right tools is very important. I can help with both …
Saw Chain Parts You Must Know
- Drive Lengths: Connects the cutters and tie straps, while guiding the chain around the bar and sprocket
- Tie Straps: Used to assemble chain loops.
- Rivets: Bind the drive lengths and tie straps together.
- Cutter: The cutting component of your chain.
- Depth Gauge, aka “Rakers” or “Drags”
- Working Corner
- Side Plate
- Top Plate & Line (Line = Angle to Sharpen & the End-of-Life Condition)
Anatomy in line, we now need to make sure that we have the right tools. The necessities are going to be a round file, a file guide, flat file and a depth gauge tool (see picture below). Most of your local farm or hardware stores, will carry each of these components individually but you can also order from online outlets like Oregon Products’ UFOUNDIT platform. With as little information as your brand and model of chainsaw, the UFOUNDIT platform will not only provide you proper saw chain products, but also the properly matched tools to fit your chain. I recently picked up the Oregon Chainsaw Sharpening Kit, as it included both the relevant tools for my saw chain and a good mix of extra field tools for my saw. It has a proven a good buy. Having the properly matched tools, specifically the proper size of round file, is vital in maintaining an accurate sharpening.
When picking your round file, you need to match the size of your file to the pitch of your chain. This becomes an easy matching process after identifying the pitch of your chain. You can do this by measuring the distance between the center points of three consecutive rivets of your chain or by simply referring to the pitch measurement on your chain package. In the table below, you can see a few common file diameters matched with the correlating pitch.
Chain Pitch – Round File Diameter
- 1/4" – 4.0mm
- .325" – 4.8mm
- 3/8" – 5.2mm
- .404" – 5.5mm
As a little bit of added information, there are different chain design types which aren’t going to be as relevant to this process. That said, know that the two ends of the commercial spectrum are Chisel Cutter and Chamfer-Chisel Cutter chains. The Chisel Cutter is designed to cut fast and efficiently but will wear fast in dirty environments, whereas the Chamfer-Chisel design is built to better last and handle the wear of dirty environments. For most management projects, I would lean in the direction of the Chamfer-Chisel design.
Lastly … always, always, use protection where it makes sense. In this instance, cutters can get sharp, and a pair of thin utility gloves can prevent bloody fingers or knuckles.
Better knowledge of your chain parts, proper tools in hand and your chain type identified, we are ready to begin assessing your chain. We are looking for signs of damage versus common wear that comes with a well-used saw chain.
Just like inspecting your hunting knife, signs of damage would resemble big nicks, dents or chunks out of the sharp edge between the gullet and working corner of your cutter. If you are minding your chainsaw blade while cutting, doing your best to keep it out of the soil and away from rocks or old barbed-wire fences, we should only see wear.
What does wear look like? Again, I would reference the comparison of the blade of your hunting knife relative to the area between the gusset and your working corner. Obviously, our saw chain is not going to need the fine edge of a boning knife, but we also don’t want rounded, smooth or dull edges. Wear is going to present a smooth feel on the cutter edge that may even be rounded in some cases. We want to target achieving a good sharp edge between our gusset and working corner of the cutter.
Time to File
Pick up your tools, it’s time to get to work! Let’s first assume that you only see signs of wear on your saw chain. We are going to file with both your round and flat files, but the round file and guard are first. With your round file in hand, we are going to reference the engraved line on the top plate of the cutter, which is going to provide you the angle of orientation for your file as you only file towards the outside. This orientation and filing example are provided below.
At that angle, place your file inside the cutting edge of your gullet and begin to file toward the outside of your cutter. Most importantly, keep your file level with the ground or perpendicular to the vertical plane of the bar. As a good rule of thumb, make three outward filing strokes and then check your edge. If your edge still feels dull or if you can still visually notice a rounded edge on the gullet or working corner, continue until both are gone. Once done, move to the next cutter and repeat all the way around your chain.
Let’s address what to do if you identify damage to your saw chain. Identify the cutter with the most damage to it’s edge and we will want to start filing here. The process will be much the same of what you exercised with simple wear, but the difference will be that more filing strokes will be required. Rather than exercising the “three strokes and check method,” you will want to continue to file the damaged cutter edge until the blemishes are removed from your edge. It is very IMPORTANT that you count the number of strokes that it takes to remove this damage. You will need to apply an equal number of strokes to each cutter, whether damaged or not, to keep a consistent depth in each gullet around the chain. This will promote equal performance with each cutter.
Important to note … in the event that filing past the damage also means filing to a point beyond your engraved angle on the top plate, resharpening that chain will not be an option. Instead, it will be time to use Oregon’s UFOUNDIT platform to order a new chain!
With a fresh edge now on every cutter, we need to check each of the depth gauges (aka rakers and drags) with the depth gauge tool and flat file. Place the depth gauge tool over the cutters with only the depth gauge exposed in between. With the depth gauge tool, you want to maintain two points of contact on each side of the exposed depth gauge. If the depth gauge sticks above the plane of the tool, place an inside to outside stroke with your flat file at a plane perpendicular to the vertical plane of the bar. File your depth gauge down to a level that is flat with your gauge tool and repeat on every depth gauge around the chain.
That’s it! You are ready to go. Keep your P.P.E. in play, bar/chain oil running and fuel reservoir full. Hopefully, this tutorial will save you some time, some money and keep you more efficient in timber management efforts.
For more instruction and tips on chainsaw and saw chain maintenance, check out Oregon Tool’s YouTube Technical Tips for Forestry playlist here.