CP9121BR - Air Grinder Tool, Welder, Woodworking, Automotive Car Detailing, Stainless Steel Polisher, Heavy Duty, Right Angle Grinder, 5 Inch (125 mm), 0.8 HP / 600 W - 12000 RPM

I bought this to replace my Ingersoll Rand 3445 air angle grinder. What's not clear in the descriptions is: Is the red body of the CP9121 plastic or metal? I glad to report IT IS DEFINITELY METAL. Very likely powder-coated aluminum. (Of course I don't want to scratch it and see for sure.) This unit has the rugged build I was looking for. I noticed what looks like this exact same grinder, same color, under different branding and very close to the same price elsewhere, but sorry, I forgot the exact brands. Note: If money is no object you should also be looking at the Ingersoll Rand G2 series grinders, which are supposed to be super industrial duty. Another competing product is the IR 3445. I had the first version of the IR 3445 (the non-MAX version) and it broke within a year. (I use these for removing mill scale from structural steel.) Although I am partial to IR air tools, I will never get a "composite construction" (read metal/plastic) air tool again. One drop and the housing cracked at the aluminum/plastic joint, and IR doesn't sell the plastic replacement part separately. You have to buy a whole new housing which costs $100 minimum. This (the CP9121) seems a little more noisy than the my previous grinder, but heck, I'm always wearing ear muffs anyways. I will gladly trade the slight noise difference for something durable.

Works great just keep it oiled.

Description says this has a “spindle lock for easy grinding wheel changes.” It does not have a spindle lock and requires tools.

Chicago Pneumatic CP9121BR Heavy Duty 5-Inch Angle Grinder with 5/8-Inch, 11 Spindle I have purchased two of these grinders and will continue to use these as replacements for years to come. These grinders are put to the test in a large metal fabrication shop. The company I work for has been through many different pneumatic grinders over the years, and for the money, these are the best I've found.

It just shot craps after just 3 years of moderate use.

Only used the grinder for a couple hours so far. I am so far very happy with it. No problems and like it better than an electric grinder

Take it from someone who repairs these for a living, and I've rebuilt dozens upon dozens of them. They don't last long without a rebuild. And many of them fail so catastrophically that they can't be repaired. I have several sitting on the shelf that can't be repaired because the cylinders are stuck inside the body of the tool. Several others have bearings stuck in their caps because there is no way to get them out. I just cannibalize them for parts. Some dumb engineer at C.P. didn't plan for the maintenance of these tools. Let's put it this way: we no longer buy them. We switched to Dynabrade and have way fewer issues.

I bought this for my husband who works in a structural steel fabrication shop. he has used it almost everyday for the past 3 months and hasn't had a single problem.