Selecting a grinder wheel

I needed a new grinder wheel so, as I usually do, I researched "grinder wheel". This is information I came up with. There are two pieces of important information pertaining to selecting a wheel. First is the "type" found in the upper center of the wheel. There are three basic types - 27, 28 and 29. For cut-off operation, you will ALWAYS want Type 27. The second letter/number indicator is more subjective. Below is information for selecting the proper one (including explaining the "TYPES"):

WHEEL TYPE/THICKNESS APPLICATIONS
TYPE 27
Type 27 wheels are essentially straight wheels that have a “depressed center/raised
hub”. Different types of fiberglass reinforcement mesh give the product stability for
use on the periphery, on the face, or a combination of the two.
.
■■
TYPE 28
Type 28 wheels are constructed with a downward angle built into the grinding
section to facilitate a flatter grinding angle. These wheels can only be used on the
face and never on the periphery for cutting-off.
■
TYPE 29
Type 29 wheels are constructed with an upward angle built into the grinding section
to provide full face contact for light stock removal and blending operations. These
wheels can only be used on the face and never on the periphery for cutting-off.
1/8" Type 29 Flexible, AVOS
Polishing and blending applications.

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These are found to the left of the Type:

A24N - Fast Cutting



Aluminum oxide grain
General purpose
Soft bond for fast stock removal
Use for ferrous metals (iron, cast iron, etc.), Low grade stainless steel



A24R - General Purpose

Aluminum oxide grain
Provides consistent performance with long life
Use for ferrous metals (steel, angle iron, rebar)



A30S - General Purpose

Special aluminum oxide grain formula
Fast, non-binding cutting
Use for ferrous metals, Stainless steel, high tensile alloys


Stationery Saw Cut-Off Wheels
A36R - Burr-Free

Aluminum oxide grain
A finer grit for burr-free finish
Use for ferrous metals (metal tubing, etc.), Stainless steel, high tensile steel


A36T - Fast Cutting

Aluminum oxide grain
Hard bond for aggressive cutting on rough applications
Use for ferrous metals (iron, steel, welds, etc.) Stainless steel


A46N - Aluminum (Non-Ferrous Metals)

Aluminum oxide grain
Soft bond for aggressive cutting without loading
Use with reusable 5/8-11 adaptor to fit angle grinders
Use for non-ferrous metals (aluminum, copper, brass, etc.)



A60S - General Purpose

Thin 0.045 width
Use with reusable 5/8-11 adaptor to fit angle grinders
Extremely fast cutting with long life
Use for ferrous and non-ferrous metals (iron, steel, welds, etc)


A60T - Burr Free

Hard bond for smooth cutting
For use in nuclear, aerospace, automotive, foundry industries, and plant maintenance
Use for ferrous metals (iron, steel, welds, etc.) High tensile metals