Chainsaws come, ready for use, with three integrated power sources: rechargeable battery, electric or with a petrol engine. When appraising each unit, it is helpful to be aware that, no matter the power source, all types of chainsaw are assembled from the same constituent parts:
The power provision will come from either an electrical motor, or an internal combustion engine. The latter come with either two stroke or four stroke engines.
A centrifugal clutch provides a connection from the engine to the chain. Along with a sprocket (a notched wheel that connects the chain) this makes up the chainsaw’s driving mechanism.
Available in a variety of lengths, a guide bar is elongated and has a rounded end with a slot that controls the chain.
A cutting chain is a sectional line of teeth, each tooth connected by a rivet. It will have cutting edges created from a creased tab of metal which, for reasons of safety and efficiency, will always correspond in size to any guide bar length.
Guide Bar Length and Cutting Chain
Guide bar length is measured from the leading tip of the chain, down to the point where it enters the motor housing, and dictates the largest piece of wood that the chainsaw can cut in a single pass. The longer the bar, the more power will be required to run the chainsaw effectively, but the length must also be appropriate for reasons of safety: if the bar is too or too long it may 'kick back' into the operator, causing injury.
For paring modest sized trees, minimal amounts of lumber and minor foliage.
Bar length of 8 to 14 inches.
For more habitual use when chopping timber, small trees and logs.
Bar lengths of 14 to 20 inches.
Generally preferred by professionals. Also invaluable when undertaking habitual, voluminous, more substantial tasks.
Bar lengths greater than 20 inches.
Although the size of a guide bar should match the undertaking, it should also be noted that a bar will wear more quickly on the bottom, where the cutting chains connect with the target. An easy way to ensure an even wear pattern is to rotate it, either when replacing a chain or at some other predetermined interval, such as after every twenty hours of usage. To estimate the particular size of chain needed for any specific guide bar there are three, basic measurements:
The gauge (bar groove) is defined by the link thickness where it fits into the guide bar and dictates the depth of the cut made by each tooth in the chain.
The pitch is the average distance between two rivets. As this distance can vary, pitch can be measured by calculating the breadth between three of the rivets and then halving it. Pitch measurement must match the sprocket so that the chain will not slip or cut poorly.
The chain length is qualified by how many links are in the chain and should match both guide bar and sprocket teeth. Measuring length is often easiest by simply counting the links on the old one.
Cutting chains can be bought in ready-joined lengths, and all chainsaws have adjustable mounts to allow such chains to be tightened to a perfect fit. Chain is also available in bulk, stored on reels or spools, which can be cut to the requisite length then joined by manually inserting rivet pins.
How to File a Blunt Cutting Chain
There is a simple, step-by-step process to be followed in order to properly sharpen damaged chains. Over-sharpening is not to be recommended as, unless each individual tooth is no shorter than ¼ inch, there is a high risk of breakage during normal operations.
Determine the gauge of the chain.
There are a number of files and sharpeners available for chain link sharpening. The wrong file will further damage the chain, likely making it useless, so check the instruction sheet that may accompany a new chain, or use a depth gauge to determine the file size required.
Clean the chain carefully.
Ensure that all cleaning fluids are minimally applied when removing dirt and old chain oil as excessive application may damage the engine parts or housing.
Use a vice for safety and stability.
Clamp the bar in a vice, leaving the chain to rotate naturally. By securing the guide bar and chain in this way there is also less risk of accident or injury during the sharpening process.
Mark the first tooth.
Earmarking the start point ensures that teeth are not foreshortened, and allows them to be filed equally.
Mirror the file angle for each tooth.
It is preferable to copy the angle of the original machining whilst filing. Indeed, some manufacturers even have markers to aid the process.
Use a twisting motion.
Starting with the short edge and moving towards the longer point should sharpen to a smoother surface. By using a gentle twisting motion the tiny metal filings produced during sharpening should be easily discarded.
Always file the tooth using the same angle.
As the sharpening process progresses, ensure that all teeth are filed on the apex of the guide bar by spinning the chain.
Flip the saw to finish the job.
Reverse the bar to allow a continuous movement, and help to make sure that all teeth are an equal length.
How to Replace a Chain
Before replacing a chain, take a moment to clear out any debris or wood chips from the centre of the rail, check that the oil hole is clear and make sure that there are no burrs on the bar rails; if there are, file them off.
Remove the guide bar panel.
Make sure that the brake is off before going any further; a locked brake will make it incredibly difficult to reassemble the engine housing. Two nuts usually secure the panel. Unscrew them and move the side panel to access the cutting chain.
Release the chain tension.
The tensioning screw is located on the inside of the guide bar. When the chain has some slack, lift the links and slip them over and around the clutch.
Loosen the tensioning screw further.
By giving additional slack, this should make installing the new chain much easier.
Thread, align, and tighten.
Thread the chain onto the bar in a reverse of removal, pulling on the nose to add tension. Whilst doing this, ensure that the bar is settled onto the adjustment pin and lightly tighten the tension screw, leaving enough slack to properly reassemble the housing.
Replace the guide bar panel.
Although refitting the panel, only loosely tighten the nuts so the guide bar can move a little so that the chain can be properly tightened.
Adjust the tension.
With the tension screw, re-tighten the chain to a suitable level.
Finish tightening the side panel nuts.
Make sure that all fittings are now properly tightened and in place. Now the chainsaw is ready for use.
How to Remove a Link
As well as being dulled, a chain can also be ‘stretched’ but, with the correct tools, removing a link can shorten the chain and render it suitable for use again:
Prepare the chain.
Put the chain on a flat, even surface. Turn the handle on the tool, the arm will retract, then the tool can be fitted over the desired link by lining up the arm with the pin.
Remove the pin.
Turn the handle until the pin is forced from the link then do the same on the other side, at which point it will be possible to pull the link from the chain.
Reconnect the chain.
Line up the link ends, put the pin in the hole and position the tool over the link. Now, turn the handle until the pin is back in place.
How to Buy a Chain File for a Chainsaw on eBay
To buy chain files on eBay, head to the homepage and open the All Categories tab. After choosing the link for Home & Garden, opt for Garden in the side bar, then click on Power Tools & Equipment from the drop down menu. Next, look for Chainsaw Parts & Accessories in the left hand menu and pick Chain Sharpener/File from the filter options. Available item listings will then be available for consideration. Otherwise, it is easy to use the search bar displayed at the top of any eBay page. For example, to find a chain file, simply type in “chainsaw chain file”.
A chainsaw, irrespective of the power source, is constructed from the same, basic components. Although the cutting chain and guide bar must correlate for safety, it is also necessary to perform regular checks on the rails, oil hole, and cutting edges to extend the working life of the tool.