Welding Digest

Metal grinding is a demanding job. But it can be made easier by choosing the right product and the right tool for the specific application and using them properly.

When an application calls for weld blending, bevel creation, or heavy material removal to get a part to a certain dimension, portable grinding wheels are an efficient choice. However, getting the best performance out of grinding wheels requires attention to a few key factors.

Grinding Wheel Options

Portable grinding wheels, which are typically used on handheld right-angle grinders, provide versatility and portability because they can be taken to the workpiece. They are also capable of removing a lot of material quickly. This helps operations focus on productivity and move on to the next job faster.

To choose the right grinding wheel, it’s important to consider the needs and requirements of the application, including the workpiece material, the tool being used, and the desired result. Many factors differ from wheel to wheel. Different abrasive grains, resin formulations, additives, and fiberglass reinforcements all play a role in the results, along with wheel performance and life.

Tips for Improving Productivity

Making the tough job of grinding as productive as possible comes down to several factors.

Tip 1: Choose tools carefully

Tool power makes a big difference in grinding wheel performance. If the tool doesn’t have enough power or torque, the operator won’t get the full performance of the wheel as it’s designed. For example, a product that contains ceramic alumina requires a higher-powered tool to ensure that the operator gets the full advantages of the self-sharpening grain. Even something that seems small, like the choice of the extension cord, can affect wheel performance.

Tip 2: Start with a pull motion

With a new grinding wheel, start by using a pull motion, rather than a push motion, for the first few strokes. This helps break in the edge of the wheel, prevents initial gouging of the workpiece, and familiarizes the operator with wheel performance. If the application allows it, use long, smooth movements and avoid short, choppy strokes. This gives consistent material removal in the work area and reduces the chance of digging into the workpiece, which can create costly rework.

Tip 3: Don’t dwell

It’s important to keep steady, consistent movements and avoid dwelling in the same spot when using a grinding wheel. Otherwise, heat will build up and could cause discoloration on high-value workpieces. Dwelling in the same spot can also result in removing too much material, potentially adding costly rework.

Tip 4: Use proper pressure and orientation 

Operators may think that pressing harder will get the work done faster, but too much pressure on a grinding wheel can cause problems and increase operator fatigue. Use moderate pressure and let the wheel do the work. The orientation of the wheel to the workpiece also plays an important role in performance and productivity. The optimal angle for using a grinding wheel is typically 25 to 35 deg. It can be used safely at a shallower or steeper angle depending on the application, but you will not achieve the same life or efficiency. Make sure your technique matches the instructions on the wheel. If it says the wheel is for vertical use only, don’t use the wheel to grind on its face.

Tip 5: Optimize wheel life

Using a wheel for its full usable life helps operations reduce wheel costs as well as the downtime spent on changeover, which in turn helps improve uptime and productivity. Take advantage of technologies that help optimize wheel life.

Tip 6: Keep a focus on safety

Some simple things to keep in mind include making sure the maximum rpm listed on the product is higher than the maximum rpm listed on the tool. Also, be sure the wheel fits under the tool guard that is installed on the grinder and keep the guard on the grinder. Edge chipping or breaking can become a safety hazard if fragments fly off the wheel while it’s in use.

Tip 7: Consider the application

One of the first steps in choosing the right wheel for the application is to consider the job being done. Specific wheel designs and formulations are available for many applications and materials. For example, in multipass welding, grinding typically happens right after the root pass weld is completed, which means the weld can still be very hot. Look for a grinding wheel designed to break down on hot welds, which reduces wheel chatter and glazing. Foundry applications are also examples of very specific applications that require wheels designed for that work. Grinding in a foundry often involves working with hard-to-grind materials using powerful tools, so it requires a wheel that holds up to heavy pressure and higher torque to avoid premature edge breakage. In addition, to avoid contaminating materials like aluminum and stainless steel during grinding, choose contaminant-free wheels designed specifically for those materials. Aluminum is a softer metal with a lower melting point than steel, so use a wheel specifically formulated to break down and not load up with aluminum material to maintain higher productivity.

Getting the Most Out of Grinding Wheels Making a demanding job like grinding as safe, comfortable, and productive as possible involves attention to several factors, including product selection, proper technique, and the needs of the application. Following these best practices can help improve productivity with grinding wheels.

This article was written by Tony Hufford (category manager, metal fabrication, Weiler Abrasives, Cresco, Pa.) for the American Welding Society.