Techniques of Effective Grinding
These 6 techniques on how to grind effectively can increase your safety and productivity. Safety is a paramount concern when handling highly abrasive machines. Productivity is a bonus, especially in mass production.
6 Technique of Effective Grinding
Use the Right Tool
Power tools should be used according to the purpose for which they were designed. This is true for angle grinders, which are designed for use on metals.
Your primary consideration: The needed amperage for the job. Choose an appropriate grinder with enough amperage for the task at hand.
For example, if the job calls for 8 to 10 amps of pressure, you should choose a 10-amp angle grinder. Otherwise, you’re already in trouble from the start.
Keep in mind that power tools aren’t consumables. You shouldn’t treat angle grinders as throwaway tools. So it makes sense to spend more money on high-quality products.
Grinding discs, in contrast, are consumables. You can change a grinding disc but be sure that it’s a high-quality one. You’re likely to get better results when both are compatible in quality.
Use the Guard
Safety is closely tied with effectiveness and efficiency. The safer you are when using power tools, the more effective and efficient you can be. For this reason, using the guard is a must for effective grinding.
The guard can be a slight nuisance sometimes but keep it on. First, you have reduced risks for injuries, not to mention the hefty fines from OSHA. Second, you’re more likely to see the work piece with it on.
Even when you have to grind in tight areas, you have to keep the guard on. You shouldn’t use a right-angle grinder as a shortcut measure. Your best choice is a file grinder, which will make the job finish faster and safer.
A few tips about changing abrasive media:
- Unplug the grinder first.
- Turn the grinder’s head up.
- Lock the key button.
- Rest the grinder on your forearm.
- Take the disc off while it’s facing up (i.e., for better control).
If you drop the abrasive, you shouldn’t put it back on. Even a hairline crack can be dangerous when the disc’s in use.
Look and Listen
You have to use your eyes and ears in determining whether you’re applying proper pressure or not. You can also use an ammeter but your eyes and ears should still be at work.
- Look at the ammeter readings on a regular basis. In general, the optimal pressure is between 8 and 10 amps. Below 8 amps means exerting more pressure. Above 10 amps means lessening the pressure.
- Look at the sparks flowing from the work piece. In most jobs, the sparks should have a consistent flow 3 to 4 feet away from the work piece. This means the grinding wheel’s grains are removing excess weld metal.
The sparks won’t be flowing well when you’re either pushing too hard or too little. If you’re not pushing hard enough, the grains aren’t fully engaging the work piece.
If you’re pushing too hard, the disc overloads resulting in the grains becoming smooth. There's reduced spark production in this case.
- Listen to the grinder’s sound. If you hear a more or less constant pitch, then the grinder’s properly engaged. If not, you’re either putting in too much or too little pressure.
You’re overworking the grinder when its pitch decreases. Think of the sound of a paper shredder being fed too many papers at once. You should decrease the pressure exerted on the grinder.
You’re not exerting enough pressure when the pitch increases. You’re likely to hear a high-pitched sound coupled with chattering noises.This is the result of the disc bouncing across the excess weld metal’s ridges. You have to push a little harder.
Mind Your Working Angle
The grinding discs are best used at a working angle between 5 and 10 degrees from the horizontal. You can use a protractor to measure the angle between the grinder and work piece for starters. Your eyes should be able to judge the angle after a few tries.
You may also look at the disc’s wear patterns and thickness. The rule of thumb: The wear pattern should be double the thickness.
If the disc is 0.25-inch in thickness, its wear pattern should be 0.5-inch. If the wear pattern is higher, your angle of approach is too flat. If it’s lower, your approach is too high.
Keep a Consistent Pressure
Keeping a consistent pressure on the forward and backward motions is a must. You should avoid excessive hard and light pressure on both motions. You want the disc’s grains to do their work - no more, no less.
Adapt Your Technique
Moving the grinder’s disc forward and backward works well for standard mild steel materials. But you have to adopt your technique according to the material. For example, stainless less can be a “gummy” material so its treatment will be different.
You must then adapt your technique according to the material and grinding disc used. You can use the pull-lift-and-repeat method on stainless steel and certain aluminum alloys.
You can lessen the bluing effect on the metal surfaces. The metal has a moment to cool down between the strokes).
Your work will be faster, easier and safer with these techniques of effective grinding. You have to be in the moment, so to speak, since all your senses should be used during the process.
Your eyes must be on the lookout for the spark flow and angle of approach. Your ears must listen to the grinder’s sound. Your informed judgment can determine the best grinding technique for the material.
These techniques demand practice to perfect. You have to start now and get going on it! Soon enough, you have mastered the techniques and passed them on.