Chicago Pneumatic Air Grinders
Thirty-three pneumatic grinder models — die grinders from the $106 CP875 to governed industrial machines, angle grinders from 2 to 9 in., vertical grinders for foundry duty, and a 60,000 rpm pencil grinder for die work. Air grinders run cooler than electric under continuous load and never worry about duty cycle.
The short version
Three questions pick the grinder: what abrasive (burr in a collet, wheel, or disc), what size, and how many hours a day. Carbide burrs and small stones → die grinders; cut-and-grind discs → angle grinders; heavy stock removal on castings → vertical and heavy angle grinders; wheels on a spindle → straight grinders. Continuous production duty belongs to the governed CP3000-series industrial line in industrial die grinders. Everything lives in the grinders category; abrasives and collets are in grinding accessories. Sizing help: 1-888-883-5144.
Die Grinders — Shop and Automotive Line
1/4 in. collet grinders for deburring, weld dressing, porting, and casting cleanup — the tools every fab bench owns.
Burr-and-collet workhorses
The CP875 is the default shop die grinder in half the garages in America; the pistol-grip CP9107 covers awkward angles, and the 60,000 rpm CP9104Q pencil grinder does die and mold detail a full-size tool cannot touch. Kit versions add collets, wrenches, and a case.
Die Grinder · 1/4 in. Collet
22,500 rpm · 1/4 in. collet
The shop-standard die grinder — deburring, weld dressing, general stock removal.
Configuration
Die Grinder · Pistol Grip
17,000 rpm · 1/4 in. collet
Pistol grip when the work angle rules out a straight-body grinder.
Collet max capacity
Die Grinder · 6 Body Styles
22,000-28,000 rpm · 1/4 in. collet
Straight, long, 90-degree and 120-degree bodies on one part family.
Air consumption at free speed / Angle Type
Pencil Grinder · 60,000 RPM
60,000 rpm · 1/4 in. collet
Fine die work, mold finishing, and detail deburring in tight pockets.
Configuration
Die Grinder · Governed
25,000 rpm · 1/4 in. collet
Governed motor holds speed under load for consistent finish.
Housing
Die Grinder · Extended Option
24,000 rpm · 1/4 in. collet
Standard or extended shaft to reach into bores and cavities.
Shaft
Die Grinder · Heavy Duty
12,000-13,000 rpm · 4-5 in. wheel
Slower, stronger grinder for larger mounted wheels and discs.
Wheel
Industrial Die Grinders — CP3000 Series
The CP3xxx industrial line: governed motors that hold rated speed under load, built for shifts of continuous grinding in foundries and fab plants.
Governed grinders for production duty
These are a different animal from shop die grinders — governed vane motors, industrial bearings, and speed options from 1,000 to 40,000 rpm, with CNOMO mounting versions for fixtured production cells. When a grinder runs six hours a day, this is the line that survives it.
Industrial Die Grinder
15,000-30,000 rpm · 11 versions
The base industrial die grinder — pick power and exhaust direction.
11 configurations
Spec it on the product page — 11 buildable versions.
Industrial Die Grinder
18,000-30,000 rpm · 300-500 W
Compact industrial grinder in three power classes.
Speed / Power
Industrial Die Grinder
20,000-40,000 rpm · 17 versions
The high-speed specialist — up to 40,000 rpm, CNOMO options.
9 configurations
Spec it on the product page — 9 buildable versions.
Industrial Angle Die Grinder
9,000-20,000 rpm · angle head
Angle-head burr work inside castings and weldments.
Speed / Exhaust
Industrial Die Grinder
15,000-28,000 rpm · router option
Mid-frame industrial grinder; includes a router-tool version.
9 configurations
Spec it on the product page — 9 buildable versions.
Industrial Die Grinder · Low Speed
1,000-22,000 rpm · 26 versions
The specialist range — speeds down to 1,000 rpm for carbide and flap work.
13 configurations
Spec it on the product page — 13 buildable versions.
Industrial Die Grinder
18,000 rpm · 1/4 in. collet
Heavy-frame single-speed grinder for hard continuous duty.
Type
Industrial Die Grinder
12,000-18,000 rpm · angle or straight
One-horsepower class grinder in straight, angle, and extended builds.
Speed / Head
Air Angle Grinders
Cut-off and grinding discs at a right angle — weld cleanup, edge breaking, and surface prep where an electric grinder overheats or does not fit.
Disc work from 2 to 5 in.
Air angle grinders earn their keep on duty cycle: no brushes to cook and no thermal cutout mid-weld-pass. The 2 in. CP7500D gets into corners a 4-1/2 in. tool cannot; the CP7540 and CP9120 families cover the standard 4-5 in. disc sizes with US and metric spindles.
Angle Grinder · 2 in.
22,000 rpm · 2 in. wheel
Small angle head for weld cleanup where a 4-1/2 in. grinder will not fit.
Configuration
Angle Grinder · 4-5 in.
12,000 rpm · 4-5 in. disc
General-purpose angle grinding with US or metric spindle threads.
Wheel / Spindle
Angle Grinder · 4-5 in.
12,000 rpm · 4-5 in. disc
The step-up shop angle grinder; five buildable versions.
Wheel / Spindle
Angle Grinder · Industrial
13,500 rpm · 4 in. wheel
Industrial-line 4 in. grinder, standard or extended handle.
Handle
Angle Grinder · Industrial
12,000 rpm · 4 – 4-1/2 – 5 in.
Governed industrial grinder in the three common disc sizes.
Wheel
Angle Grinder · 2-4 in.
13,500-20,000 rpm · 2-4 in. wheel
Small-disc industrial angle grinder for precision weld dressing.
Speed / Wheel
Angle Grinder · Industrial
13,000 rpm · 4 in. wheel
Mid-frame industrial angle grinder, standard or extended shaft.
Shaft
Angle Grinder · 4-6 in.
10,000-12,000 rpm · 4-6 in. disc
One-horsepower angle grinder up to 6 in. discs.
Wheel / Spindle
Heavy Angle & Vertical Grinders
7-9 in. wheels, autobalancer options, and vertical grinders built for snagging castings and grinding weld seams all shift.
Foundry and heavy-fab stock removal
At 7 in. and up, vibration is the enemy — the CP3650 and CP3850 offer autobalancer versions that cut operator vibration dramatically, and the vertical CP3330/3340/3349 line is the foundry standard for snag grinding. The turbine-motor CP3T30 is quote-only; we spec it with CP.
Angle Grinder · 4-1/2 – 6 in.
10,000-12,000 rpm · autobalancer
Premium industrial angle grinder; autobalancer versions available.
Wheel / Autobalancer
Angle Grinder · 7-9 in.
6,000-8,500 rpm · 7-9 in. wheel
Big-disc angle grinder for plate, castings, and heavy weldments.
Speed / Wheel
Angle Grinder · 7 in.
8,500 rpm · 7 in. wheel
Single-size 7 in. workhorse for fab-shop grinding.
Spindle
Turbine Angle Grinder · 5-7 in.
8,500-12,000 rpm · turbine motor
Turbine power-to-weight for production grinding. Call to quote.
Vertical Grinder · 6-9 in.
6,000-8,500 rpm · vertical
Vertical grinder for snagging castings and surface work.
Wheel
Vertical Grinder · 6-9 in.
6,000-8,500 rpm · vertical
Heavier vertical frame for continuous foundry duty.
Wheel
Vertical Grinder · Overspeed Shut-Off
6,500-8,500 rpm · safety shut-off
Adds overspeed shut-off and anti-vibration options for compliance-driven sites.
Wheel
Straight Grinders
Inline grinders for mounted wheels and cones — weld seams inside vessels, fabrication cleanup, and grinding where the wheel has to run in line with the body.
Wheels on a spindle, inline body
Straight grinders carry the wheel on an inline spindle, which is what you want inside pipe, tanks, and weld seams. The CP3119 runs to 18,000 rpm with multiple spindle threads; the CP3249 is the heavy 6-8 in. wheel machine with overspeed shut-off options.
Straight Grinder · 3 in.
18,000 rpm · 3 in. disc
Compact inline grinder for seams and corners.
Type
Straight Grinder · 2-1/2 – 4 in.
12,000-18,000 rpm · 7 versions
The versatile inline machine; multiple speeds and spindle threads.
Wheel / Wheel thickness
Straight Grinder · 6-8 in.
4,500-6,000 rpm · 6-8 in. wheel
Big-wheel straight grinder for heavy fabrication and foundry work.
Wheel / Speed
Air Grinders — Common Questions
What is the difference between a die grinder and an angle grinder?
A die grinder spins a small burr or mounted stone held in a collet, inline with the body — precision material removal, deburring, porting. An angle grinder spins a disc at 90 degrees to the body — surface grinding and cutting with much more coverage per pass. If the job is measured in thousandths, it is die grinder work; if it is measured in square inches, angle grinder.
Why buy an air grinder instead of electric?
Duty cycle and survival. A vane air motor makes full power all shift, does not overheat, stalls harmlessly when you lean on it, and shrugs off the grinding dust that kills electric brushes and windings. It is also lighter for the same power. The trade is a compressor: most of these tools want a serious shop-air supply for continuous use, so check the CFM figure on the product page before you buy.
How much air does an air die grinder use?
Small die grinders like the CP875 sip a few CFM in intermittent use, but continuous grinding is a different story — a working industrial grinder can demand 10-25 CFM at 90 psi, and a 7 in. angle grinder more still. The CFM figure on each product page is the honest number to size against. Two grinders on one compressor means adding their consumption, not averaging it. Call 1-888-883-5144 to sanity-check your setup.
What does a governed air motor do?
An ungoverned grinder loses speed the moment you load it. A governed motor meters air to hold rated rpm under load, so the abrasive keeps cutting at its designed surface speed — faster stock removal, better finish, longer abrasive life. That is the main thing the industrial CP3xxx line buys you over shop-grade grinders, and why production cells spec it.
What is a CNOMO mount?
A French-origin standard interface for mounting air tools into automated fixtures and machine cells. Several CP3019 and CP3119 die grinder versions come CNOMO-ready so a machine builder can bolt them straight into a deburring station. If you are hand-holding the tool, you do not need it — buy the standard version.
Do you stock abrasives and collets for these grinders?
Yes — burrs, cut-off wheels, grinding discs, and mounted points in abrasives, and backing pads, guards, collets, and spindles in grinding and sanding accessories. Genuine CP collets matter on the high-speed tools — a worn collet at 60,000 rpm is a thrown burr.
Which CP die grinder should a fab shop buy first?
The CP875. It is $106, covers deburring and weld dressing with any 1/4 in. shank burr, and survives shop life. Add the pistol-grip CP9107 for awkward angles and step up to the governed CP9113G or the industrial CP3xxx line when the grinder becomes a production tool rather than a bench tool. Sanding instead of grinding? See air sanders and polishers.
Need Help Picking an Air Grinder?
We stock the full CP grinder line in Denver. Call for help matching a grinder to your abrasive, your compressor, and your duty cycle.