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The Milwaukee tools their 4-1/2” Small Angle Grinder is typical of Milwaukee tools and exceptional to just about everyone else's!
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Milwaukee 4-1/2” Small Angle Grinder

Power, durability and dependability the Milwaukee way

Text, photos and video by Tom Hintz

Posted – 6-9-2011

If you work with metal and don’t like babying mediocre tools you probably have more than a few from Milwaukee Tools in your collection. This Milwaukee 4-1/2” Small Angle Grinder is just one of many angle grinders that they make but the features that this one (#6146-30) has and how they fit my way of metalworking seemed to be a good match. Metal is tough but we have to be a little tougher to get it to do what we want. Milwaukee tools help me gain that advantage over the metals that lets me work better, easier and safer.

The Basics

The Milwaukee 4-1/2” Small Angle Grinder easily fits the absolute basic description of a 4-1/2” angle grinder but from there it exceeds expectation in every way. Perhaps most visually obvious is the super-tough plastic housing that protects the innards with a durability that defeats even harsh work environments. This is a double insulating system so it also protects you from stray electricity.

The shape of the body provides an easily gripped surface that gives the user a solid feel of control. The large outboard handle gives the operator far more control (and safety) than using any angle grinder single-handed. The outboard handle can be installed from the left or right to accommodate both left and right-handed users.

The body of this grinder (left) is tough, well-made and surprisingly comfortable. the paddle-style On/Off switch (right) is easy to use for left and right-handed operators.
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With an overall length of 11-1/2” and a trim 5.4 LB total weight the Milwaukee 4-1/2” Small Angle Grinder makes all day jobs easier to handle. The balance of the Milwaukee 4-1/2” Small Angle Grinder during use also contributes to reduced strain on the operators’ part. The 8-foot-long, two-wire cord lets you work more and look for other places to plug into less.

The Milwaukee 4-1/2” Small Angle Grinder with its 5/8"-11 spindle thread uses standard 4-1/2” grinder accessories like disks and wire brushes. A specially formed (included) spanner wrench and a very easy to use pushbutton spindle lock make changing disks fast and easy. The shape of the spanner wrench makes changing disks easier even with gloved hands.

The Milwaukee 4-1/2” Small Angle Grinder kit as shown here includes the grinder itself, a tool-free Type 27 Guard, a grinding disk, side handle, spanner wrench, flange and flange nut and a contractor bag to help protect your investment during transport.

Controlled Power

The Milwaukee 4-1/2” Small Angle Grinder sports a very stout 11 Amp, 120V only, 11,000 RPM motor that is designed to deliver maximum performance with Milwaukee’s fabled durability. This motor is rated at 1400 MWO (Max Watts Out =Power).

To insure long term durability the motor has an internal overload protection. It also has an electronic clutch that extends the life of this tool and helps prevent dangerous bind-ups. Milwaukee also added the Soft Start feature to this motor that eliminates the hard torque response on start up. Soft Start is also a safety factor.

The extra-sturdy guard (left) can be removed, installed and repositioned by pressing this button! The disk changing system (right) is simple to use and very fast.
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To further protect the motor Milwaukee uses what they call an “Advanced Airflow System” that uses the airflow generated by the motors cooling fan to help keep grinding debris from entering the motor housing. That directed airflow can substantially increase the life of this tool in an environment contaminated with air born bits of metal and stone.

The motor is controlled by an easy to use paddle type On/Off switch. The paddle switch is centered on the housing to make it equally accessible for left or right-handed operators. The paddle switch has a pushbutton lockout just ahead of it that must be depressed to engage the paddle. I know this sounds clumsy but it really is not. The lock out button can be easily depressed with a finger and the Milwaukee 4-1/2” Small Angle Grinder started by squeezing the paddle. Push that same lockout switch a bit deeper while the Milwaukee 4-1/2” Small Angle Grinder is operating and you can lock it in the On position. To release the lock-on feature simply squeeze the paddle just a little and the button pops out releasing the paddle switch back into the Off position.

Good Guard

The Milwaukee 4-1/2” Small Angle Grinder uses a very tough Type 27 shield that is installed and positioned without tools. The Milwaukee literature call this guard “burst resistant” and it certainly looks to be all of that and more. It is formed from heavy gauge steel and just looks more formidable than many other angle grinder guards I have depended on in the past.

Unlike some tool-free guards the Milwaukee 4-1/2” Small Angle Grinder version locks solidly in place when the pushbutton release returns to the locked position. And the guard can be rotated to several operating positions by simply pushing the release button. That makes it easy to put the guard in the best position to protect you as you move through a job and have to grind at different angles. The ease with which this guard can be adjusted eliminates all of the already weak excuses for not using a guard.

In the Shop

The grips (left) are comfortable to the hand and make controlling this grinder a no-stress chore. Milwaukee even uses the cooling fans airflow(right) to help keep debris out of the motor to prolong its life.
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One of the first things I noticed about the Milwaukee 4-1/2” Small Angle Grinder is the ultra-clean manufacturing of its components. Everything fits very well and the spindle turns very smoothly. Rock the spindle back and forth and you feel very little play, something that indicates precise manufacturing which in turn allows proper alignment of the gears for smooth power transfer and a long life.

The paddle switch is easy to operate but does have a definite “click” feeling when it goes into the On position. The lockout button and that click virtually eliminate accidental startups. Locking the Milwaukee 4-1/2” Small Angle Grinder in the On position for long jobs is slightly more difficult because the lock button has to be depressed further to lock the paddle in the On position. That is a good thing though as we want to know that a grinder is locked on and this system insures that we realize that.

When grinding metal the Milwaukee 4-1/2” Small Angle Grinder seems to be just cruising along with no indication that running out of power is drawing near. You can slow the motor somewhat if you lean on it hard enough but that level of force is way beyond what is reasonable. And, if you lean on it hard enough the electronic clutch will kick in and stop you from damaging the motor by stalling it. If you suspect that this electronic clutch is sort of an idiot-proofing device you would be right. If you lean on the Milwaukee 4-1/2” Small Angle Grinder hard enough to trip the electronic clutch you can be certain that you just did something dumb.

The Milwaukee 4-1/2” Small Angle Grinder runs very smoothly which makes it more comfortable to use even when tackling a big job. The gears run very smoothly and quietly which also limits the vibrations felt by the operator through the handles. No shaking or vibrating, just lots of power applied smoothly so you can get a better looking finish on the metal quicker.

Video Tour

The disk changing spindle lock and wrench work very easily so you can install a fresh disk (or accessory) and get back to work quickly. The tool-free guard is also a welcome addition that lets you reposition the guard as the job progresses and save a little more time in the process.


If you like Milwaukee tools their 4-1/2” Small Angle Grinder will seem like an old friend. It is very well built, designed to be easy to use and packs the power you want for your jobs. Milwaukee’s 5-year warranty shows their confidence in this tool as well.

With a street price hovering around $99.00 (6-8-2011) taking advantage of the Milwaukee 4-1/2” Small Angle Grinder capabilities makes good fiscal sense. Whether you are a pro contractor or just want good tools in your home workshop, the Milwaukee 4-1/2” Small Angle Grinder deserves a hard look when you need a tool such as this.

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