Sizes of the tools ranged from the 15 1/2-inch-long DeWalt (on left) weighing 6.3 pounds to the 11 5/8-inch-long, 5-pound Hitachi. A big part of the extra bulk of the DeWalt is the rear grip with its large D-shaped handle guard. Finish grinding—especially radius grinding on three-dimensional objects—is much easier with a small, maneuverable grinder such as the Hitachi or the Bosch or Ridgid. Such compact tools can even be used one-handed for light-duty grinding when your other hand is needed to steady the workpiece.
Ridgid’s guard can be rotated to the desired position by simply using your thumb to push a spring-loaded lever that unlocks the guard. Tool-free guard adjustments also can be found on the DeWalt, Hilti, Metabo, and Milwaukee grinders.
The Hitachi (shown) and Bosch grinders both require the use of a tool to adjust their guards. The Hitachi needs a Phillips screwdriver, which is not included. The Phillips-head machine screw is difficult to tighten solidly and in the rough environment at the front of an angle grinder, I think a slotted or hex head screw would be better for securing the guard. The Bosch uses a hex wrench, which stores in a rubber slot down by the battery, but leaving it there isn’t recommended because it readily falls off. By having to stop and find a tool to adjust the guards, the extra hassle makes it less likely that a needed adjustment will be made.
The Bosch, DeWalt, and Milwaukee (shown) each come with two guards: a standard Type 27 grinder guard (on right in photo) and a more enclosed Type 1 cut-off wheel guard that provides greater personal protection in the event that a sharp cut-off wheel throws fragments into shrapnel at high speed. DeWalt, Hilti, and Milwaukee grinders all come with 5-inch guards, giving them the flexibility to be used with either 4 1/2- or 5-inch accessories.
Side handles for the grinders can be threaded into the right or left side of the tool, and in the case of the Ridgid, also in a third position straight up above the head of the tool. Some handles are perpendicular, such as the Milwaukee (left) or are steeply angled like the Bosch (right). Angled handles provide a wider grip stance but can get in the way at the front of the tool. I didn’t have a preference, and in fact, the experts at the fabrication shop usually use the tools without front handles so they can grip the tool closer to the front to improve handling. The rubber bushing in the Milwaukee’s handle noticeably isolates vibration from your hand.
Instead of a dedicated cut-off wheel guard, the Hilti has a plastic cover that snaps over its 5-inch grinder guard.
Metabo’s battery can be rotated and clicked into four positions, keeping it out of your way. Pointing the toe end sideways (as shown) lets you get closer to a flat surface. Pointing the toe end down keeps it from bumping into your arm.
Removable filter screens on the Metabo (shown) and the Milwaukee models keep abrasive particles from getting sucked into the motor windings. The screen can be removed for maximum air flow or cleaning. The Milwaukee comes with a spare replacement screen.
There are three types of grinder switches. The trigger switch on the DeWalt (left) can be locked off but not locked on so it offers the least amount of grip flexibility. Bosch, (center), Hitachi, Milwaukee, and Ridgid feature lock-on slider switches. These offer the best freedom of motion for both the tool and your hand position. But if the grinder were ever to get away from you while running, look out! The Metabo (right) and Hilti have paddle switches, also called a “dead man switch” because if you let go of the tool, it stops. There’s a safety lever that must be pushed for the switch to work to prevent the tool from turning on if it’s set down on its trigger. Once on, you can move your hand around somewhat as long as it’s still holding down the switch, so it is possible to choke up on the tool to shift your grip forward.
DeWalt’s handle provides knuckle protection, but because you have to hold the trigger on, you can’t move your rear hand to choke up for a different grip. Having your hand stuck at the back of the grinder (plus its extra length) costs the tool some maneuverability.