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An Average Circular Saw, Satisfactory For Home Owner Use
on November 21, 2010
At the current time, cordless saws have noticeably less power than corded tools. The DeWalt DC390 is no exception to this. It will certainly cut 2" thick fir and pine lumber, but you won't get the same rate of production as with a corded saw.
This saw has a thick base plate, which I like. Thinner stamped metal base plates on circular saws often get bent after several years of use and the saws never work well after this happens.
A routine use of the DeWalt DC390 will be to cut thin stock such as plywood. It's handy to have a cordless tool for this purpose since you often have to extend your reach to make cuts. However, this saw is poorly balanced for such work. With the cut depth set shallow, the battery is raised high and the saw is top heavy. If you put the saw down as you would a normal circular saw, it will tip over. The lower half of the saw guard is made of a slightly flexible plastic. Given this saw is likely to tip off worktables frequently, I think this is better than having a metal guard which might get permanently bent. Plywood is often cut using a guide such as a bar of metal clamped to the work. It is difficult to cut with the DeWalt DC390 while keeping it snug to a guide because, in addition to the trigger, the saw has a safety that must be pressed with your thumb. It prevents you from wrapping your thumb around the handle, so you don't have a normal grip. (The DC390 also suffers from a weakness of all direct drive circular saws in that the motor leaves little clearance under it and tends to bump into any clamps that you use to hold the guide. It seems to me that manufacturers could do a better job of designing a motor housing that provided more clearance, even if only when the saw is set to do shallow cuts and motor is raised relatively high.)
The locking knobs for the bevel and depth of cut are made of hard plastic. I find them comfortable to use.
The saw uses a 6 1/2 inch diameter blade with a 5/8 inch arbor hole. The blade included with the saw has 16 teeth and is for rough carpentry. (It is easy to find a variety blades that fit this saw in hardware stores. Don't buy a blade with a 10 mm arbor by mistake.) The arbor bolt is reversed threaded and must be tightened with a hex key. The key is provided and it can be stored securely by pressing it into slots in the body of the saw.
Like many cordless saws, this is a "left handed" saw, which has the blade mounted on the left side of the motor. For a right handed person, the consequences of a "left handed" saw are these: When you cut along a marked line, you will be able to see where the blade is cutting clearly because the motor won't be in the way. However, when you perform the typical operation of holding a board down with your left hand while you cut off the right end of the board, the wider part of the saw's base is resting on the wood that will bend and fall away. The saw also tends to tilt and fall away. You have to apply attention and force to keep the base of the saw level.
This particular product offer ( DC390B, "tool only") does not include a battery for the saw or a charger. The saw's shipping weight is listed as 8 lbs ( about the weight of a plastic gallon jug of water) and, to me, this feels correct for the weight of the tool. Attaching a battery adds weight. At the current time ( Nov. 2010) DeWalt makes both 18 V Nicad batteries and more expensive and lighter 18 V lithium batteries that fit its 18V cordless tools.
I rate this saw as three stars out of five to indicate that it is an average cordless saw. It may be a better than average deal depending on your requirements and its current price.