Chainsaws are powerful tools that allow users to cut through wood quickly and efficiently. One of the most important components of a chainsaw is the bar and chain. The bar is the long metal piece that the chain wraps around and slides along, while the chain has sharp cutters that remove material as it rotates around the bar.
Most chainsaw bars have a small hole located along the top edge near the tip. This hole serves an important purpose for proper function and maintenance of the saw. In this article, we will discuss what the hole on a chainsaw bar is for and why it is an important feature.
Allows you to mount the bar
The primary function of the hole on a chainsaw bar is to allow you to mount the bar onto the chainsaw. On most chainsaws, there is a bolt that fits through this hole and secures the bar to the body of the saw.
Without this hole, there would be no way to properly attach and align the bar so that the chain can ride along it smoothly. The hole ensures the bar stays in the correct position in relation to the rest of the saw components like the clutch and chain tensioner.
This allows the operator to have full control over the bar and maintain proper chain tension for safe and efficient cutting. The hole is precisely positioned to line up with the corresponding mounting point on the saw.
Guides the chain
In addition to mounting the bar in place, the hole also helps guide the chain along the bar’s track. As the chain rotates around the bar, it has a tendency to want to derail or come out of the groove on the bar. The presence of the hole helps keep the chain centered in the groove.
As the chain comes around the tip of the bar, it passes partially over the hole. This prevents the chain from sliding too far to one side or the other as it comes around the tip. It essentially funnels the chain back into the correct position to re-enter the groove properly.
Without the hole, the chain would be more prone to derailing, especially when operating at higher speeds. Having a guide for the chain results in smoother operation and less wear and tear over time.
Allows access for maintenance
The hole on a chainsaw bar also facilitates maintenance and cleaning. Sawdust and debris can build up inside the groove where the chain rides. If too much accumulates, it can begin to obstruct the free movement of the chain.
The hole provides an entry point to access the interior of the bar groove so you can clear out any debris. You can insert a narrow tool, air nozzle, or solvent tip through the hole to remove dirt, sap, sawdust, etc. This is often necessary after cutting very resinous wood or if you notice performance starting to decline due to buildup.
In addition, you can lubricate the inside of the bar through the hole. By squirting bar and chain oil into the hole, you can replenish the lubrication along the entire bar surface to minimize friction and wear.
Without the ability to perform this type of cleaning and maintenance, the bar groove would become fouled more quickly. So the hole is an important aspect of reducing wear and tear over the life of the bar.
Allows insertion of bumper spikes
Some chainsaw bars are designed to have additional bumper spikes that can be inserted into the tip. These spikes provide leverage when cutting by preventing the tip from bouncing or slipping along the surface of the wood.
On bars equipped for them, the bumper spikes slide into holes at the end of the bar and are secured in place with set screws. The main mounting hole is used to insert the spikes into the bar and get them properly lined up with the positioning holes.
Without this hole, there would be no way to add these helpful spikes to aid in cutting performance for certain situations like bucking logs. The ability to add bumper spikes expands the functionality of bars and saws equipped for their use.
Serves as a lubrication channel
On some chainsaw bar designs, the mounting hole doubles as a lubrication channel to help carry chain oil along the bar. Special guide bars will have an angled channel leading from the hole out to the edge of the bar.
| Bar Type | Lubrication Method |
|---|---|
| Standard bar | No lubrication channel |
| Guide bar | Lubrication channel connects hole to bar groove |
As oil pumps out of the hole, it is guided along this channel to help spread lubrication across the entire length of the bar. This ensures optimal lubrication across the entire bar surface to reduce heat and friction.
The angled design draws oil from the hole and uses capillary action to pull it laterally along the channel. This gets bar oil to the tip without the need for any additional ports or holes.
On bars without this feature, the chain has to carry the oil from the Oilomizer outlet to the tip. A lubrication channel helps take some of this burden off the chain to enhance oiling performance.
Facilitates hand filing
The hole on a chainsaw bar can also make it easier to hand file the bar. Filing helps keep the rails and groove of the bar in optimum condition for smooth chain movement and extended bar life.
Normally, filing requires removing the bar and chain from the saw. But by utilizing the mounting hole, you can lock the chain break and insert a file holder to steady the file against the bar surface. This allows for convenient filing without fully removing components.
The ability to file the bar while still mounted provides a stable platform and perfectly straight filing action. The hole technique eliminates hassles of repositioning and lining up the file by hand for consistent results.
While it takes practice to master proper chainsaw bar filing techniques, the hole facilitates quick and accurate maintenance filing sessions to keep the bar rails smooth and updated.
Conclusion
The hole on a chainsaw bar may seem insignificant, but it actually serves a range of important purposes. It allows the bar to be mounted to the saw, helps guide the chain, provides access for cleaning and maintenance, enables adding bumper spikes, distributes lubrication on some models, and can aid in hand filing processes.
This simple hole contributes to the safe, efficient, and long-lasting performance of the bar and chain. Without it, operating and maintaining your saw would become much more difficult and hazardous.
So next time you look at your chainsaw bar, you can appreciate just how vital that small hole is for functionality. Proper use and care will allow your saw’s bar and chain to keep working reliably for many seasons of woodcutting work.