Abrasive Finishing Explained

It really depends on who is being asked the question, but generally if all employees of a metal fabrication shop are polled to see which department is the “worst”, there will likely be a lot of votes for grinding/deburr department.

While their reason may vary dramatically, it really comes down to one (or all) of the following reasons.

  • It can be physically demanding
  • It’s “dirty”
  • It’s a mindless job
  • It should only be for entry level workers [you don’t typically make a great salary in these positions].

But there are passionate workers who grind steel, aluminum and stainless all day long and absolutely love it. Let’s take a few minutes to dive deep into this subject today.

What is Grinding?

Grinding in this context is the removal of excess material from a work piece in an effort to improve the surface finish, remove scale/rust, or to shape a particular type of material for further process.

What kind of industry needs a process like this?

While anybody can walk into a big box store and pick up an electric grinder that only requires a standard 110V outlet, there are businesses that require these tools for production. Just to name a handful:

  • Metal Fabrication or Welding
  • Auto Body
  • Auto Mechanics
  • Machining
  • Sculpture foundries / Artists
  • Construction

Applications

For a few of the industries, grinding is used to remove weld from a work piece or to remove material therefore allowing better weld penetration and a stronger fusion of two or more pieces into one new part.

Even some artists choose to work in some type of metal and prefer to use a grinder with some technique to achieve a look they’re after. Whether the final product is a roughly ground surface, or starts out as rough, and is polished through higher “grit” grinding/sanding disks, it’s an interesting process to follow along.

Types of Grinders

There are various shapes, sizes and types of grinders depending on the needs of the business or individual.

  • Bench GrinderA bench grinder is a bench top type of grinding machine used to drive abrasive wheels. These can be used to shape parts prior to welding, or to sharpen cutting tools and bits. Also, when fitted with a “soft fibrous wheel” these can be used to break sharp edges making parts safer to handle.
  • Die Grinder – Named after the reason this tool was created, it was originally used to shape and grind out dies” or “molds”. These are used for precise shaping, honing, sanding, polishing, etc. For fine detail work.
  • Angle Grinder – This is a handheld power tool used for abrasive cutting or polishing. These can be powered by electric motors, gas, or compressed air depending on the model/type purchased. These are by far the most common in the electric version because they’re useful and readily available to anyone, even without special equipment to power it.

Personal Experience

I have personally was exposed to abrasive finishing (grinding) in my junior year of High School when I enrolled in an Auto Body Refinishing class at a technical school.

What types have I used?

Of the three types I have listed above, I’ve used all of them. They’re equally useful in their own right, but by a long shot I have used a 4-1/2″ Makita angle grinder more than any other tool when it comes to abrasive finishing.

On what applications?

Since I have worked in a “job shop” for the last 5 years, through several departments of the company, I’ve spent some time helping out in the grinding department.

A “job shop” is a business that will take orders from large companies (B2B), or from walk-in customers (B2C) if they’re capable of handling the order in question. It’s a really fun place to work because there is repeat work, but not everything is the same day after day.

I’ve worked on everything from large frames for the semiconductor industry, all the way to a replacement door for a crane and many things in between.

Materials like aluminum are ultra common to see through the shop I work in, but we do a fair amount of mild steel and stainless steel work as well. Stainless requires the most finesse of the three in order to achieve a “great grind”.

Technique

While boring tasks seem to plague others, I’ve always found a weird enjoyment out of the mundane tasks. I push myself harder to find a faster way, a better way, all while not compromising my own integrity. [I do not sacrifice quality for any reason, even if that means being a day late on a delivery, it must be done well].

Where I work, a lot of the grinding is done on enclosures, and the customers look for “seamless edges”, so for instance a box (with no top or bottom) can be bent out of a flat piece of material and one edge would have to be welded to make it seamless.

That edge has to be ground and sanded smooth to look like the bent sides. That’s where the technique comes into play.

Taking care not to grind the flat surfaces, and maintaining a diligent eye to only remove the welded portion will allow for easier sanding afterward.

Holding a grinder perfectly flat against a surface area as small as a radius edge can be difficult, but it can be honed with time and practice.

By starting from one edge and moving in a semi-slow sweeping motion (depending on the grit of the disk), achieving a smooth, seamless transition can be easy.

Safety

This is so important when it comes to working in a dangerous environment that requires the use of a grinder.

You’ll want to protect vital parts of your body (this means the parts that you can’t afford to lose, or get replaced).

Gear

  • Safety Glasses (Even with safety glasses on, there still is a potential to get foreign debris in your eye(s) while grinding, just be aware and smart about where you position your face, grinder, and work piece).
  • Leather Apron (Not a fashion statement, but you’ll thank me when your t-shirt isn’t catching fire from the sparks constantly being thrown at it)
  • Gloves (These WILL NOT stop a grinding disk from cutting you… The disk will tear right through the glove if it’s caught just right… Trust me. But they’ll protect your hands from hot sparks, surfaces and sharp edges created from grinding).
  • Boots (Not a necessity I suppose, but it’s nice to have leather, steel-toed boots keep your feet safe from stray sparks or falling parts).
  • Hearing Protection (This should be as obvious as the safety glasses. Grinders get LOUD, and the will mess with your ears if you don’t take the steps to protect them).

Practices

Be aware of your surroundings, your work piece and the tools being used. It’s very easy to catch a tight corner with a grinding disk and have it become violent quickly.

When these torque devils catch a corner, they’re usually coming toward you, and it can hurt.

When all else fails, drop the grinder, stay out of it’s path and unplug it from the outlet.

How to start being a grinder

So, something about this line of work interests you?

GREAT!

It’s really enjoyable to some people, and to others it’s not. That’s okay!

The best place to start would be at a metal fabrication shop looking for an entry level grinder/polisher. These jobs can be found on all of the big job sites and sometimes in local want-ads. They’ll show you the ropes, and if they don’t, you can always find it on YouTube.

Once you’ve gained some experience at a shop as a “newbie”, and you’re confident in your results, you can ask for an increase in pay if the place is nice and the people are good. If not, then look for a shop hiring “experienced grinder/polishers”.

When it comes to entry level… You’re looking at low pay. It will likely be close to minimum wage for your area, or perhaps a little higher. In NY, entry level grinders should expect to make between $11/hr – $14/hr to start in 2019.

Willingness to Improve

Too many people are just “okay” with a good enough mentality.

I can understand that some things really are just good enough. But, that doesn’t mean settling is acceptable.

Pushing the limits to improve, and never stop improving is the difference between a “good worker” and “great worker”.

So practicing a skill is as important as learning it on day one to improve.

“How you do one thing is how you do everything” – Anonymous

This quote should mean a lot to everybody. It demands discipline in all aspects of life, and it’s a true quote.

If someone doesn’t take pride in things like keeping the inside of their car relatively clean, then they’re not going to have the discipline to make the hard decisions either.

[I’m exaggerating with this example, but it’s to prove a point that everything “MATTERS”, and if people slack in one area, they’re likely to slack in another or ALL other areas of their life as well].

No matter how “insignificant” the job is… Do it to the best of your ability.

Be the best damn grinder in the company. It’s not a glamorous job, but it’s a job that has to be done.

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