How Do You Sharpen Chainsaw Chains? (Step-by-Step Guide & Key Techniques)

Understanding Chainsaw Chain Sharpening

Sharpening a chainsaw chain is the process of restoring the sharp cutting edges on each cutter tooth and ensuring the depth gauges (also called rakers) are at the correct height. A sharp chain is not just about performance; it’s a critical safety feature. A dull chain requires excessive force, increases the risk of kickback, and produces fine, powdery sawdust instead of clean wood chips.

The key parts of the chain relevant to sharpening are:

• Cutter Tooth: The sharp, angled blade that does the actual cutting. It has a top plate and a side plate, both of which form the cutting edge.
• Depth Gauge (Raker): The small, shark-fin-shaped piece in front of each cutter tooth. It controls how deep the cutter bites into the wood. If the depth gauge is too high, the chain won’t cut; if it’s too low, the chain will grab and increase kickback risk.
• Pitch: The distance between any three consecutive rivets on the chain, divided by two. This measurement is crucial for selecting the correct file size.

Key Factors for Choosing a Sharpening Method

There are three primary methods for sharpening a chainsaw chain, each with its own considerations.

Manual Filing (Most Common DIY Method)

• Pros: Inexpensive, portable, allows for precise control, and can be done in the field. It’s the most common skill for chainsaw owners to learn.
• Cons: Requires practice to master, is time-consuming, and relies on user skill for consistency.

Electric Chain Sharpeners

• Pros: Fast and efficient, especially for sharpening many chains. They use a grinding wheel and can restore a very sharp edge quickly.
• Cons: More expensive, less portable, and can remove more metal than necessary if used improperly, potentially shortening the chain’s lifespan. They are best for workshop use.

Professional Sharpening Service

• Pros: Guarantees a factory-spec sharp edge and is the best option if a chain is badly damaged, twisted, or if you lack the tools or confidence.
• Cons: Costs money, requires downtime without your saw, and you lose the convenience of doing it yourself.

Your frequency of use is a major factor. For occasional users, manual filing is usually sufficient. For professionals or those cutting daily, investing in an electric sharpener or having a rotation of professionally sharpened chains may be more practical.

Step-by-Step Guide to Manual Chain Filing

This guide focuses on the manual filing method, which is essential knowledge for any chainsaw owner.

1. Safety Precautions and Preparation

• Always ensure the chainsaw is turned off and the spark plug wire is disconnected.
• Secure the chainsaw in a vise or on a stable workbench to prevent movement.
• Wear safety glasses and gloves.
• Clean the chain thoroughly with a brush to remove sawdust and debris, which can dull your file and obscure the cutting edges.

2. Determine the Correct File Size and Angle

The correct file size is determined by the chain’s pitch. The pitch is usually stamped on the drive link of the chain or listed in the chainsaw’s manual. Use this guide:

The standard filing angle for most chains is 30 degrees. A file guide is highly recommended for beginners. It sits on top of the chain and holds the file at the correct angle and height.

3. The Filing Technique for Cutter Teeth

1. Place the file in the gullet (the curved space) of a cutter tooth, resting it against the top plate.
2. Using the file guide, ensure the file is at the correct 30-degree angle relative to the bar.
3. Apply firm, even pressure and push the file forward in a smooth stroke. Lift the file on the return stroke to avoid dulling it.
4. Make consistent, equal strokes for each tooth. Typically, 3-5 strokes are needed. The goal is to remove just enough metal to create a fresh, sharp edge.
5. After sharpening one tooth, move to the next cutter on the same side of the chain (all left-hand cutters, then all right-hand cutters). This ensures even sharpening.
6. Use a marker to color the top of the first tooth you sharpen. This helps you track your progress and know when you’ve completed a full rotation.

4. Checking and Adjusting Depth Gauges (Rakers)

After sharpening the cutters, check the depth gauges. They should be slightly lower than the cutter teeth. Use a depth gauge tool (a flat metal template) and a flat file.

1. Place the depth gauge tool over a cutter tooth. The tool has slots for the cutter and the depth gauge.
2. If the depth gauge protrudes above the tool’s surface, it needs filing.
3. Use a flat file to carefully file the top of the depth gauge down until it is flush with the tool. File only the front, rounded portion.
4. Check every depth gauge. Incorrect raker height is a major cause of poor cutting and dangerous kickback.

5. Signs of a Correctly Sharpened Chain

• The cutting edges of the top and side plates are shiny and sharp to the touch (be careful!).
• All cutters on one side are of equal length.
• The chain produces clean, large wood chips when cutting, not fine sawdust.
• The saw pulls itself into the wood with minimal pressure from the operator.

Maintaining Your Sharpened Chain

Proper maintenance extends the life of your sharp edge.

• Cleaning: After use, clean the chain and bar groove with a stiff brush or compressed air to remove sap and debris.
• Tensioning: Check and adjust chain tension before each use. A loose chain can derail and dull quickly. A properly tensioned chain should snap back against the bar when pulled.
• Lubrication: Always ensure the chain oil reservoir is full. Proper lubrication reduces friction and heat, which are the enemies of a sharp edge.
• Storage: When storing the saw for long periods, slightly loosen the chain tension to relieve stress on the rivets.

Frequently Asked Questions

How often should I sharpen my chainsaw chain?

There is no fixed schedule. Sharpen your chain whenever it shows signs of dullness: when it starts producing fine sawdust instead of chips, when you have to apply excessive pressure to cut, or when the chain pulls to one side. For most users, this could be after every tank of fuel or after cutting a certain amount of wood.

Can I sharpen a chain with an electric sharpener without removing it from the saw?

Yes, many electric chain sharpeners are designed to be used with the chain still on the saw. The saw is clamped into the sharpener’s vise, and the grinding wheel is brought to the chain. This is efficient but requires careful setup to ensure the correct angle.

What is the difference between filing the cutter and filing the depth gauge?

Filing the cutter tooth restores the sharp cutting edge. Filing the depth gauge (raker) adjusts how deep that cutter can bite into the wood. Both are essential. If you only sharpen cutters without checking depth gauges, the chain will eventually stop cutting effectively.

Is it worth sharpening a chain myself or should I take it to a professional?

Learning to sharpen your own chain is a valuable and cost-effective skill for any chainsaw owner. It allows for immediate maintenance in the field. However, if a chain is very badly damaged, has been sharpened unevenly many times, or if you are not confident in your ability, a professional service can restore it to factory specifications and is a safer option.