Tracking down the right dcs391 parts shouldn't feel like a full-time job, but anyone who has ever had their circular saw quit in the middle of a deck build knows how frustrating it can be. The DeWalt DCS391 is a fantastic 20V workhorse, but like any tool that spends its life chewing through 2x4s and plywood, things are going to wear out eventually. Whether it's a trigger that's gone mushy or a base plate that's seen one too many drops off a sawhorse, most of these issues are actually pretty easy to fix yourself if you can get your hands on the right components.
One of the most common reasons people start hunting for dcs391 parts is the motor brushes. Now, if you've noticed your saw is starting to lose power, or maybe you're seeing a bit more sparking than usual through the vents, there's a good chance those little carbon blocks are just worn down to the nubs. It's a cheap fix, and honestly, it's a lot better than buying a whole new tool. The tricky part is making sure you're looking at the right "Type" for your saw. DeWalt loves to update their designs, so you'll usually see a "Type 1" or "Type 2" on the nameplate. Always check that first because a Type 1 brush set might not play nice with a Type 10 motor housing.
The bits that usually break first
It's usually the small things that get you. I can't tell you how many times I've seen guys searching for dcs391 parts specifically because they lost the blade wrench or the arbor bolt. It's easy to do—you're changing a blade in the grass, you set the bolt down, and suddenly it's gone into the void. The arbor bolt and the inner/outer flanges are essential for keeping that blade spinning true. If your blade is wobbling, don't just tighten it harder; check the flanges for debris or rounding. Replacing these is a five-minute job that can save your motor from unnecessary vibration.
Then there's the lower guard. This is a big safety item, and the spring inside that guard is one of those dcs391 parts that takes a lot of abuse. Over time, sawdust gets packed into the pivot point, or the spring just loses its tension, and suddenly the guard isn't snapping back like it should. That's a recipe for a trip to the ER. If your guard is sticking, you can sometimes clean it out with compressed air, but if the spring is snapped, you're better off just replacing the whole guard assembly. It's not worth the risk of "fixing" it with a rubber band.
Dealing with the shoe and adjustment levers
Let's talk about the shoe—the big flat base of the saw. The DCS391 uses a magnesium shoe, which is great because it's light and strong, but it isn't invincible. If you drop the saw onto concrete, that shoe can bend. Once it's out of square, your cuts will never be straight again, no matter how steady your hand is. Searching for dcs391 parts for the base is common after a tool takes a tumble. While you're at it, check the bevel adjustment lever and the depth adjustment lever. These are often made of plastic or thin metal and can snap if they're forced.
Replacing the shoe is a bit more involved than changing a blade, but it's definitely doable. You'll usually have to deal with a few pivot pins and some retaining rings. If you're doing this, keep track of the small washers. I've spent more time looking for a dropped washer in the sawdust than I have actually fixing the tool. It's those tiny dcs391 parts that'll drive you crazy if you aren't organized.
Electrical gremlins and the trigger switch
If your saw just flat-out won't start, and you know the battery is charged, the problem is likely the switch or the wiring. The trigger is another one of those dcs391 parts that handles a lot of stress. Sawdust is the enemy here; it gets inside the switch housing and gums up the contacts. You might find that you have to pull the trigger "just right" to get it to fire up. That's a clear sign the switch is on its way out.
When you open up the handle to replace the switch, take a second to look at the wires. Sometimes a wire will vibrate loose or get pinched. If you're replacing the switch assembly, it usually comes as a single unit with the wires attached. It's a bit of a tight squeeze inside that handle, so take a photo with your phone before you start pulling wires apart. It makes putting the new dcs391 parts back in much less of a guessing game.
Finding the right part numbers
One thing that confuses people is the sheer number of dcs391 parts listed online. You'll see diagrams that look like an explosion in a clock factory. The best way to handle this is to find the "exploded view" diagram for your specific model number. DeWalt usually has these available, and they give you a reference number for every single screw and washer.
Don't just guess by looking at a tiny thumbnail image on a website. A lot of dcs391 parts look identical to parts for the corded versions or the older 18V models, but they won't fit. The 20V Max line has its own specific tolerances. If you can find the actual DeWalt part number—usually a six or seven-digit number—you'll have a much easier time getting exactly what you need.
Genuine vs. aftermarket parts
This is always a bit of a debate. You'll find plenty of "unbranded" dcs391 parts on big retail sites for half the price of the OEM (Original Equipment Manufacturer) stuff. For things like the plastic housing or maybe a handle cover, aftermarket is probably fine. But for the "guts" of the machine—the brushes, the armature, or the switch—I'd almost always stick with genuine parts.
The reason is pretty simple: heat and vibration. Aftermarket brushes might be made of a harder carbon that wears down your commutator faster, which basically kills the motor. Or a cheap switch might not have the same amp rating, leading to a meltdown during a heavy cut. When you're looking for dcs391 parts that affect how the tool actually runs, spending the extra five or ten bucks for the real deal is usually worth the peace of mind.
A quick tip: If you find a part that's "too cheap to be true," it probably is. I've seen arbor bolts made of soft steel that stripped out the first time they were tightened. Stick to reputable tool supply shops.
Maintenance to keep your saw out of the shop
The best way to avoid a frantic search for dcs391 parts is to keep the saw clean. I know, nobody wants to clean their tools after a long day, but a quick blast of compressed air into the motor housing does wonders. It clears out the fine dust that acts like sandpaper on the internal components.
Also, keep an eye on your blades. A dull blade makes the motor work twice as hard, which gets the internal dcs391 parts hot. Heat is the number one killer of cordless tools. If you're pushing the saw through a cut and it's struggling, stop and change the blade. It's cheaper to buy a new blade than it is to buy a new armature because you cooked the windings.
Check your mounting hardware regularly. Every now and then, just make sure the screws holding the handle together haven't vibrated loose. If the housing starts to gap, dust gets in, and parts start moving where they shouldn't. A little preventive maintenance goes a long way.
At the end of the day, the DCS391 is a rugged piece of kit. It's designed to be used hard, but it's also designed to be repaired. Unlike some of the cheaper "disposable" tools you find at the big box stores, you can actually get dcs391 parts and keep this thing running for a decade or more. So, if your saw starts acting up, don't chuck it in the bin. Grab the model number, find a diagram, and get to work. It's a great feeling to hear that motor hum again after you've fixed it yourself.