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DeWalt D28402K Grinder Review

by Lorenz Prem
published on February 1 2013 10:46 pm

More power is usually a good thing. It usually gets things done faster with more of a spectacle. What's not to love about that. When I had the chance to review the DeWalt D28402 angle grinder I jumped on it. This grinder is probably the most powerful grinder I can rationalize to keep around the house. Let's take a look at just how long the spark trail of the D28402 actually is. This should be fun.

The DeWalt D28402 Angle Grinder

The DeWalt D28402 is a heavy-duty 4 1/2" angle grinder. It's been engineered to work on tough problems all day long. The large, 10 amp motor provides ample power for such a small grinder. The D28402 is an industrial tool made to outperform anything in its weight class.

The D28402 is a heavy machine. The metal gearbox is married to an extraordinarily heavy motor. The entire tool feels like is was made from a single chunk of metal. Build quality and materials used are both excellent. DeWalt certainly offers quality for money; down to the heavy gauge power cord.

The tool is turned on with a paddle switch on the barrel. A spring loaded safety lever prevents accidental activation of the grinder. While the lever certainly prevents accidents, it also makes turning on the grinder somewhat awkward. The lever takes some getting used to.

The lock-on button on the D28402 is in the rear of the barrel far away from where the trigger hand can reach it. The button must be activated with the second hand. Once engaged the grinder will remain On until the paddle switch is pressed. At this point the safety lever reverses its function. It must be engaged to unlock the paddle, which in turn deactivates the motor. This might seem a little odd, but it works in the tool's favor. The safety lever allows the user to handle the grinder without having to worry that the paddle will disengage the lock-on button and motor.

There is no soft start feature. On a tool with a 10amp motor this leads to the tool being hard to control when it is turned on. The 10amp motor creates so much torque that starting the grinder while in contact with the work piece is impossible. It'll lurch in your hand no matter how hard you try to keep it still.

The tool's exhaust air is ejected through a port at the rear of the tool. This eliminates any air currents near the cutting wheel where all the dust is located. Less of the dust gets airborne, which leads to a cleaner shop.

The grinder does not have a speed control feature. The motor always turns the disk at a constant 10,000rpm.

Disk Changes

Disk changes require a standard grinder wrench, which is included in all versions of the tool. A spindle lock button at the side of the gear housing locks the arbor in place. The button is large and easy to press and hold.

The guard interferes with the wrench in some positions, but the whole operation can be made to work. It takes about a minute to change from one grinding disk to another.

The Accessories

The wheel guard rotates freely around the shaft of the motor. It is held in place with a lever actuated compression clamp. While the guard can rotate a full 360 degrees, it can only be clamped in position in places where there is enough room to fasten the lever. The motor housing does not leave enough room for the lever in ~120degrees out of all possible positions. Thankfully this only happens when the guard is directly in front of the body, which is not a very useful place to be for the guard in the first place. The tool-less guard adjustment works well when the guard is installed just above and behind the disk.

The guard itself is made from heavy metal. It is protected by a tough-wearing coating. The guard's shape is such that almost all debris is ejected at one end of the guard. Few sparks escape to the sides. The guard is deep for use with wide grinding wheels. Alternate guards in different shapes are available as accessories.

The auxiliary handle has been built around an all metal core. The grip is made from rubber for a comfortable and secure grip. The handle installs on either side of the grinder at a 90 degree angle. It threads in easily and locks down securely. Installation takes a few seconds.

The Case

The case that is included in the kit version of the D28402 is very good. From the outside it looks like a standard DeWalt tool case. In most respects the case is just that, down to the metal latches and the vacuum formed plastic. What makes this case special is the way the tool is secured in the case.

Two foam blocks molded into the lid of the case hold the tool in place. With the latches locked down the tool rests in the case without any rattles. This is unusual for DeWalt cases. The designers thought of the blade wrench too. There is a place for it alongside the barrel of the grinder. The grip, unfortunately, is left for roam free inside the case.

The Dewalt 4 1/2" Grinder Lineup

The D28402 is one of the largest and most powerful 4 1/2" grinder in DeWalt's lineup. It can be purchases with a paddle switch, or a classic slider. If you do not need all that power, the D28110 line offers a smaller motor at a considerably lower price. Its features and look mirror that of the larger D28402.

The new version of the D28402, the D28402N, use DeWalt's new dust ejection system. The system removes most dust particles from the air stream used to cool the motor. This results in much longer tool life compared to traditional motors. If you work in a dusty environment, this grinder is a good option for you.

In Use

The D28402 is a monster. It chews through anything without a problem. The motor hums along like it was not even doing any work. This grinder is probably as powerful as a 4 1/2" grinder motor needs to be. The disk cannot develop enough load to challenge the motor. Overloads seem impossible. This is a good thing, off course.

We could not find anything in our shop the D28402 did not cut through at a record pace. Even heavy duty angle iron did not stand up the grinder's brute force for long. The only problem we encountered was hard the grinder was to control. The grinder cuts so fast the user has to careful to guide it properly. The D28402 tends to break out of an established line when the user lets it. Experience user will know what to look for to combat this dynamic.

All this power leads to excellent durability. Since the motor is always functioning within its normal load limit, the D28402 keeps going all day long. We aborted our endurance test when it was clear the tool reached its maximum temperature under load.

Even when spinning in air the D28402 is an extraordinarily loud tool. Like with all grinders hearing protection is an absolute must; with the D28402 more so than most. All that power comes at a price.


The DeWalt D28402 is a powerful heavy duty 4 1/2" grinder. It has enough power to complete any task in record time. The grinder has been built to be used all day long in harsh industrial environments. This is a tool that will last a very long time.

Controllability suffers a little due to the powerful motor and high weight of the tool. The lock-on button is in an awkward position. These are minor concerns in a total package that gets the important things right. The kit version of the D28402 scores extra points with its excellent carrying case.

If you are looking for a small, industrial grade grinder the D28402 is an excellent choice. It is one of the best 4 1/2" grinders on the market. Few grinders match its performance; none are significantly better. If the price is right, you can't go wrong with this one.

D28402K Angle Grinder


Disk diameter4 1/2"
Max speed11,000 rpm
Arbor diameter5/8"
Trigger TypePaddle
Motor draw10 amp
Cord length
Length11 1/4"
Weight4.60 lbs

The Good

  • one of the most powerful 4 1/2" grinders
  • rubber handle feels good to hold
  • high duty cycle
  • durable and well-built
  • decent case
  • good spindle lock

The Bad

  • awkward trigger lock
  • loud, like all grinders
  • blade guard does not lock in all positions
About the Author
"Lorenz is the founder of Hingmy. When he is not reviewing power tools or improving the site, he is building things in his workshop or playing hockey."