As one of the most popular power tools on the market today, a worm drive circular saw can be found on almost every job site and almost every garage on the block. They are built for durability and high performance and make any number of construction and demolition projects much faster and easier to complete.

Despite its popularity, only a handful of circular saw users fully appreciate the importance of regular maintenance, and in particular keeping their worm drive circular saws properly oiled. In fact, it is common for the lubricant in these tools to become thick, dirty, and sludgey, which can extremely damage the performance of the saw and can contribute to premature wear and ultimately premature tool failure. However, with just a little lube and a little extra time from those of us who get so much work and happiness out of our worm drive circular saws, the premature demise of these tools is entirely preventable.

Before I explain how to flush these bad boys though, I’ll start with a quick tip: Users should check the oil level in their worm drive circular saws before each use. This takes only a moment and ensures that your saw will perform at its best every time you use it. Note: The oil level in the tool should never drop below the lower threads of the oil housing.

So, to continue, if you’re one of those users who doesn’t monitor your oil levels well and now has a mess of sludge on your hands and inside your saw, flushing and replacing the oil in your tool is the only way to revitalize its performance and longevity. Fortunately though, while it takes a bit longer than just filling the oil in, flushing and replacing it is a fairly simple procedure.

Disclaimer: Although it is not necessary to remove the saw blade to remove oil from a circular worm drive saw, it is always safer to remove it. This eliminates any possibility of injury to both you and the saw blade. Also, when you’re not running to the tool to heat up old oil or rinse with kerosene (*see below), make sure the tool is completely disconnected from its power source while you’re working on it.

To get started, simply let the circular saw run for about a minute. This allows the muddy oil to warm up and loosen up, making it easier to drain. Next, remove the oil plug. The oil plug is the metal nut that sits just above the oil tank (the tank must be clearly marked with pictures or text). To remove the plug, use the wrench that came with the tool (the same one you use to remove the saw blade) and twist the plug to remove it. Tilt the saw upside down to allow as much oil as possible to drain from the reservoir.

After draining the muddy oil, refill the oil tank with kerosene. Replace the oil plug and let the tool run for another minute. This pushes the kerosene everywhere and completely flushes the gearbox, clearing it and the reservoir of any residual oil buildup. Reverse the tool one more time to completely drain the kerosene from the reservoir.

Then and finally, you simply need to refill the reservoir with a brand specific lubricant. For example, if you are using a Skil saw, you must refill the reservoir with Skil oil. It is important that you use only these specific lubricants since other oils are not designed with the same characteristics.

Rest the tool on its foot on a vertical surface (such as a workbench or table) and fill the oil reservoir until oil squirts slightly from the lowest point of the oil hole (closest to the oil reservoir) and replace the oil plug.

Remember to check the oil in your worm drive circular saw before each use, fill it up when you need it, rinse the oil off when it gets nasty, and you and that circular saw should be well on your way to a long life of successful productivity.