Aircat produces some of the quietest air tools on the market, and this die grinder is no exception. They've taken a new look at die grinder design, creating an ergonomically friendly design, in a composite shell. The light weight and shape of this tool are wonderful for working long periods of time. Being a right angle die grinder, it offers better control for the user. That couples nicely with the feather trigger, allowing precise speed control. A rear exhaust makes the lower sound level possible, while also ensuring that the exhaust isn't hitting the operator in the face. The motor turns at a maximum of 20,000 RPM. High quality construction throughout ensures a long work life.
Okay, I have to admit, I’m cheating a bit on this one. When I ran into this kit from Astro, I thought it was perfect. Not only do you get a right angle die grinder, but a straight one as well. So, if one style of grinder doesn’t work out well for your project, the other will. Both are part of their ONYX series, with composite, ribbed handles for light weight and less vibration while maintaining a good grip on the tool. The lever throttle handle provides feathering control of speed, and is also a safety handle. This one is also rear exhaust, like the one form Aircat. The straight die grinder operates at a maximum speed of 25,000 RPM and the angled one at 20,000 RPM.
If you do a lot of grinding, especially a lot of heavy grinding, then this is the die grinder for you. Most die grinders are only 1/3 HP, while this one, from CP is a full 1/2 HP. To put it another way, that’s 50 percent heavier duty than the competition. That extra power helps cut through tough problems and will also help ensure that the tool lasts longer. In fact, CP is so confident in this tool, that they've recently upgraded the warranty to two years. It comes in an aluminum body for durability, with a squared-off handle to make it easier to hold onto. The exhaust is out the rear, keeping the exhaust air and any oil away from the workpiece. A built-in regulator helps you match the 24,000 RPM speed to the work. It comes with both 1/4-inch and 6mm collets.
Ingersoll Rand is a brand that the manufacturing industry has grown to trust. Their tools are all well designed, for rugged use and long life. This is proven out in this die grinder, which is built with ball-bearing construction. This is the highest speed die grinder we’ve looked at, with a maximum speed of 27,000 RPM. The composite case is ergonomically designed for comfort. The throttle is self-locking for security. Like the others we’ve looked at, this one has a rear exhaust; a must for die grinders.
I had to include this grinder, because it is rather unique. While there are a few other pencil style die grinders on the market, they are hard to find. Of all the pencil die grinders around, I’d have to say that this is the best. Working with it reminds me a lot of using my flex-shaft. This compact unit runs at a maximum speed of 56,000 RPM. A twist throttle on the grinder allows you to control that speed, setting it where you need it and leaving it there. The collet is 1/8-inch, not the 1/4-inch that is common for the other die grinders we've looked at, so finding bits for it might be a bit more challenging. However, when you've got to work in a tight space, this pencil grinder is ideal.
Metabo is known for their high-quality grinding equipment. This cordless die grinder is no exception. A bit long (17") and heavy at 4.7 pounds, it makes up for it in other ways. The 25,000 RPM motor has some unique protections built-in such as a safety shutdown that instantly disconnects the power supply if the tool jams and restart protection to prevent accidentally starting the tool. This is the only cordless die grinder I've seen that has a spindle lock for easy cutting tool changes. The long nose allows getting into tight spaces and that nose is covered with a removable rubber boot. The tool comes with two batteries, and an air-cooled charger allows fast charging without damaging the batteries.
There's a lot of attention to detail in this grinder from Makita. A stepped neck design makes it easier to get into tight spaces and even the collet nut is rounded, reducing the possibility of damage. At 25,000 RPM this grinder removes material rapidly when needed while electronic controls protect the motor and help maintain speed under load. The power switch is a slide-lock design, rather than a paddle switch that the operator has to hold on, helping reduce operator fatigue. The solid aluminum housing adds durability, vents are cut into the unit to blow away from the operator, and the barrel-grip design is compact and lightweight at only 4.4 pounds. With Makita’s fast charging time, the two 18 volt batteries for this tool are always ready to go and a low battery indicator LED flashes when it’s time to recharge.
Bosch’s cordless die grinder comes in at a shade under four pounds, beating the Makita for weight. It’s also shorter, leaving off the stepped neck that the Makita has. The tools chuck is hardened steel and ground for maximum precision and long life. This grinder is designed to be compatible with Bosch’s flexible power system, using both slim and fat pack 18 volt Li-ion batteries while the four pole motor runs at a top speed of 22,000 RPM. Motor and batteries are both electronically controlled to protect them. Although this unit comes without batteries, it does include the great Bosch L-BOXX-2 stackable case system.
Milwaukee calls their mini die grinder a “rotary tool,” but it’s essentially the same thing. This compact unit weighs only 1.3 pounds and comes with a 1/8 inch collet. It is a variable speed unit, ranging from 5,000 RPM all the way up to 32,000 RPM, making it the fastest cordless die grinder around. The 12 volt battery recharges in 30 minutes to get you back to work as quickly as possible.
Most people don’t think of a Dremel as a die grinder, but in reality, that’s what they are. Like all Dremel tools, this one has a 1/8 inch collet. This is Dremel’s most powerful cordless model, with a high performance motor and a one hour charge time. The 12 Volt Li-Ion battery is replaceable like other die grinders, not something all that common for Dremel. It’s variable speed, ranging from 5,000 RPM up to 30,000 with a convenient speed control. The unit is made with all ball-bearing construction for longer life and cooler operating temperature.