Chainsaw Bar Tool. Tips from a Professional


Chainsaw bars provide precise guidance to the chain, the primary cutting element of a chainsaw. Like the chain, the guide bars are prone to operational wear and tear. Affecting the chainsaw’s cutting performance. The wear can usually be in the form of burs and uneven rails edges. To fix these, a chainsaw bar dressing tool is used. This process will be discussed in this article.

Chainsaw bar tool:

A bar dressing tool is used to even out the burs on the guide bar rails. The tool consists of a flat-file with a straight edge. It files the uneven rail edges caused by the continuous wear and makes sure the edges are perfectly squared. While filing with a bar tool, make sure the bar is tightly clamped. Keep filing the rails till the edges appear smooth and square.

I will explain how to use a bar dressing tool in more detail in this blog post. Including how to inspect a chainsaw bar for wear, if you can straighten a bar. And if a pinched chainsaw bar can be fixed.

How to Inspect a Chainsaw Bar for Wear?

First, check if the rail’s edges have localized pits or bumps. Use a grinding bar or dressing bar to fix these rail dips. The second step is to check if the chain has any sideward play. If found, tighten the chain horizontally by hammering its rails till the play diminishes. The third step is to check for uneven rail edges resulting in the chain sitting lower on one rail and higher on another. To fix it, dress the guide bar using a special rail dressing tool.

The bar supports the chain, which can rotate up to a speed of fifty miles per hour. At such speeds, the wear rate that the bar receives upon impact from wood is significant enough to cause damage to the bar. Even though the guide bar is made up of high-quality steel plates which are hardened to sustain as much wear as possible.

The bar houses a narrow groove in which the chain sits. The edges of the bar’s groove are known as the rails. Since they are already relatively thin and are the first to receive any blows from the chain, the bar rails are highly susceptible to damage.

This chainsaw bar damage can be of three types:

1. Rail Dips

The rail’s edges have localized pits or bumps that can be easily spotted. The pressure exerted by the chain’s dynamic load can create these dips, particularly around the bar’s edges. If the dips are away from the nose and not deep enough, they can be nullified by grinding or dressing the bar.

2. Widened/Narrowed Groove

Due to rough use and improper lubrication, the groove gets widened from the sides. This can be noticed by checking if the chain has any sideward play. Widened grooves can be tightened the chain horizontally and hammering its rails till the play diminishes.

Similarly, the grooves also tend to get narrowed due to the pressure applied by two opposite faces of a log. Such a bar is known as a pinched bar. This can also be fixed by placing a screwdriver in the groove and hammering it to remove the pinch.

3. Uneven Rail Edges

Uneven rail edges are a common occurrence on guide bars that have been in use for some time. The rail’s edges could wear out and become like sharp metal strips. When the edges become more uneven, they can affect the chain operation. The chain might sit lower on one rail and higher on another. This angles chain can cut crooked.

The best way to solve the problem of uneven rails is to dress the guide bar using a special rail dressing tool. In the next paragraph, I will explain how to dress the chainsaw bar.

How do you Dress a Chainsaw Bar?

Chainsaw bar can be dressed using a flat file or a belt sander to smooth up the burs on the rail edges. A special rail dressing tool is also available, which files the bar’s rails at 90 degrees angle.

1. Using a Hand Dressing Tool:

A rail dresser is available for this purpose. This tool can be purchased at specialized stores or online. It is relatively cheap and can work well on a variety of bars. I will explain how to use this tool step-by-step:

  • Clamp the bar: Before dressing the bar, it should be clamped firmly in a fixture. A bench vise would be a great option to fix the bar. Please make sure the bar is clamped with its shortest edge in between the wise jaws and its rails facing upwards.
  • Get your dressing tool: The goal is to file the rails to clean them from the burrs. This can also be done if you have a flat-file instead of the dressing tool as given above. The advantage you get with this tool is that it can cut at a 90 degrees angle with reduced effort. Also, it’s cheap and provides good results with most bars (Stihl and Oregon).
  • File the rails: Press the dressing tool’s file against the top surface of the rails. Apply a gradual downward pressure on the rails. Slide the tool in the forward direction until you feel metallic chips being removed from the rails. Repeat the filing several times until the top edge of the rails appears smooth rather than sharp. Now, repeat the same process on the other side of the bar.

Tip: Before dressing, it is better to mark the rails using a blue marker to easily distinguish the pits and bumps once the file smoothens the rails.

– Drawback:

A major drawback of this method is that the file isn’t hard enough for certain high-end bars like Tsumura and Sugihara. It only works well for common bars like Stihl and Oregon. Furthermore, this tool can only help in the burr removal of the bar. It doesn’t square the rail edges perfectly. Also, it cannot be used to remove the rail dips along a guide bar as its hardness doesn’t allow significant material removal.  To fix the rail dips, a belt sander or a disc grinder is a good option.

2. Using a Belt Sander:

Belt sanders are pretty easy to operate. Probably the best way to dress a bar is to use the dressing tool and the sander in combination. The dresser is good at removing metal chips, but it doesn’t square the rail’s edges, due to which the chain might sit unevenly.

To use the sander, place the bar’s rails along the sander’s belt and press it inwards firmly until you get a nice, smooth finish at the rail edges. Repeat the same procedure on the bar’s other side.

In case you want some significant material removal, a hand grinder with an 80GR flat disc would be the better tool. This may be desired if your bar has developed localized bumps along the rails. In this case, a dresser tool wouldn’t be practical for that much material removal.

Can a Pinched Chainsaw Bar be Repaired?

Generally, a pinched chainsaw bar can be repaired by placing a flat head screwdriver at the pinched groove and hammering it to open the bent rails.

Pinching is referred to when the rails at the bar get squeezed inward. This can happen when you see a log supported from both ends and hangs from the middle. As you cut downwards, the opposite faces of the log exert pressure on the bar rails. Hence, they get pinched inwards from certain spots.

At those spots, the chain experiences more resistance and runs slowly as a result. Luckily, these are not hard to fix. There can be two ways to remove the rail pinching.

  • Use a flat-head screwdriver: Place the flat head of a screwdriver in the narrow region where the pinching has occurred. I would recommend you to insert it at about 30-45 degrees angle with the bar. Hit with a wooden hammer gently on the screwdriver sideways till the rails have the same width.
  • Use a metallic disc: Another good technique is to find a suitable metallic disc with the same thickness as a groove. You can insert a used washer or a grinder’s disc between the pinched rails. Move the disc back and forth till the narrowed groove is widened again.

Tip: After you straighten the rails in the above method, place a bar hook tool between the rails and lay the bar horizontally. Then, strike the rails having the bar tool with a dead blow hammer. This step ensures that the rails are perfectly straightened.

 The tool has the same thickness as the groove, and thus it fits perfectly. Make sure you use a dead blow hammer instead of a ball-peen hammer as it could dent your bar. The hook tool is not expensive and can be purchased at specialized stores or online. If you can’t find it, use any metallic disc that fits in the groove.

Can you Straighten a Chainsaw Bar?

In most cases, solid chainsaw bars can be straightened by using the correct technique. Laminated bars, on the other hand, do require more effort to straighten them perfectly.

If a chainsaw bar has bent, it can be straightened, but the residual stresses induced due to bending will shorten its lifespan. If the bend isn’t too significant, it can be straightened back to its original shape. Make sure you follow the steps mentioned below for better results:

Step 1. Use a ‘press’ or vise to straighten the chainsaw bar:

Probably the best way to straighten a bend is to apply a steady, gradual force that doesn’t damage the bar’s metallic grains. This can be done by placing the bent bar in a hydraulic or arbor press.

If a press machine isn’t available, the best choice would be to clamp the bar on a bench wise and straighten it out using a pipe wrench.

Step 2. Hammer the chainsaw bar:

After the kink is removed with the press, place the bar on an anvil. It is recommended to place rubber padding under it, especially if it’s a laminated bar, as it would lessen the damage by the hammer blows. After securing it, strike a dead blow hammer on the bar’s bent face to even out the kinks. Avoid hammering the bar’s rails as this could pinch them.

– Using a hook tool:

A good way to avoid any damage to the rails is by using a bar hook tool. It is a cheap metallic tool that can be placed in the bar’s groove due to its matching thickness. With the hook tool placed between the rails, you don’t have to worry about the rails while hammering.

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