Choosing Consumables for Manual Metal Cutting

By Tony Hufford, category manager, metal fabrication, Weiler Abrasives Group
Published in the February 2017 issue of Fabricating & Metalworking.

There are many tools and consumable options to consider when an application calls for manual metal cutting. Products that can be used span a wide range, including plasma and oxy-fuel equipment, saw blades, and diamond cutting wheels.
 
Resinoid bonded abrasive cutting wheels offer portability and affordability, making them a popular choice for many hand-held metal cutting applications.
 
There are numerous factors involved in choosing the right tool and consumable for the cutting job.
 
What to Know About Resinoid Bonded Cutting Wheels
Hand-held cutting wheels can be used in many applications — cutting sheet metal, tubing, bar stock, and angle iron; cutting out a weld for rework; and other fabrication, maintenance and repair tasks. The consumable choice is typically driven by the application needs, the tool being used, the material being cut, space available and desired cutting action.
Resinoid bonded cutting wheels offer numerous benefits that make them a good choice for many hand-held cutting applications, including:

• Extreme portability, for jobs that require the operator to take the tool to the location where the workpiece needs to be cut.
• Versatility, since they can be used to cut in many different angles.
• Fast cutting action or long life — or both.
• They tend to be a cost-effective, economical choice.

The two most popular styles for resinoid bonded abrasive cutting wheels are Type 1 and Type 27. Type 1 wheels are flat and typically used for straight-on cutting, while Type 27 wheels have a depressed center and can be used when there is interference that requires the spanner nut to be housed in the depressed area.
Resinoid bonded abrasive cutting wheels are also available in a variety of thicknesses and diameters with different arbor hole sizes. Common diameters range from 2 to 20 inches and even much larger. A popular thickness is a “0.045”-inch wheel, now commonly available with a threaded arbor attachment. One of the newest thicknesses taking hold in North America is the “1MM” thin wheel, which is extremely fast and leaves the cut almost burr-free.
Several factors impact cut-rate, speed and consumable life: the type of abrasive grain used in the wheel; style/size of fiberglass mesh; and the bonding and filler agents that hold the wheel together and release material during the cut. Grain options typically include aluminum oxide, silicon carbide, zirconia alumina, ceramic alumina and combinations of these materials.
 
Tip 1: Match Material and Size
Matching the tool’s size and rpm rating to the wheel’s size and rpm rating is important for safe and effective use. Increase performance by choosing the tool with the greatest amperage or amount of torque while staying in the wheel’s size/rpm category.
When choosing a wheel type, it’s also important to consider the type of tool and tool guard being used, as well as the size and thickness of the material being cut. Regarding tool guards, the typical one-sided open-face guard included with most grinders is acceptable with TY27 wheels, but a “half-moon” enclosed guard should be used with TY1 wheels. A larger diameter wheel is typically a better choice for cutting thicker material, so proper technique can be used without cutting from both sides of the workpiece. A thinner wheel removes less base material and can generally provide a quicker cut — but shorter wheel life. There are very thin products available that don’t sacrifice life due to their proprietary design.
Certain materials, such as stainless steel and aluminum, require the use of specialty cutting wheels. The term “INOX” on stainless steel wheels, for example, signifies that they use a contaminant-free bond. Wheels designed for cutting aluminum have additives to help reduce “gumming up” since aluminum has a lower melting point than most other commonly used metals.
 
Tip 2: Proper Positioning
Proper angle of use is another important factor with resinoid bonded abrasive cutting wheels. The proper angle is often labeled on the wheel. Typically, a cutting wheel should be used at a 90-degree angle, perpendicular to the workpiece. This doesn’t mean you can’t cut at an angle; it means stay straight when starting the cut — don’t bend the wheel like a jigsaw.
In addition, it’s important to let the cutting wheel do the work by using proper pressure. Pushing too hard on the wheel can cause the operator to lose control during the cut. To extend wheel life, cut as shallow as the application allows and use a smooth rocking motion to dissipate heat/friction. Choosing a grinder with the highest torque or amperage available for the application allows the wheel to do more of the work.
While the most efficient performance typically comes from tools and consumables that offer quick, consistent cutting, keep in mind that the thinner the wheel, the more susceptible it can be to side loading. This refers to the wheel bending when it moves side to side in the cut, which can be dangerous if the operator leans too hard on the side of the wheel.
 
Tip 3: Storage and Care 
Proper tool usage and storage also impacts safety, productivity and tool life. While choosing high-quality, durable tools are key, proper storage and maintenance is just as critical to getting the best results.
Both on the jobsite and in the shop, store products in a clean, dry environment and avoid placing them in water or mud to help maximize performance and reduce issues with cracking or wear. Resinoid bonded abrasive wheels used on right angle grinders are generally not designed to be used wet.
Also, be aware that the performance of these products will deteriorate with extended storage, so it’s good to utilize a “first in, first out” rule (FIFO).  
Inspect the tool and consumable before each use to check for signs of damage or wear. As the product wears with use, cutting wheels can become harder to control. Replace the wheel when the diameter reduces to the point that a proper cut cannot be made safely.
Following best practices for the tools and consumables used for metal cutting can help extend product life, benefit operator safety, and improve productivity and efficiency.