Working with Angle Grinders
Published by Trails Less Traveled on February 6th, 2006
Introduction
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My garage is so full of tools, parts and projects that I have to keep it pretty well organized in order to get any work done, but I use my 4” angle grinder so often that I barely ever bother to put it away. To be completely honest though, I don’t really like working with grinders. The mess and abrasive dust they make is pretty awful. I only tolerate the black boogers because it would take an entire workshop full of expensive tools to replace my 4” Makita angle grinder. It’s a good makeshift substitute for a chop saw, band saw, plasma cutter, reciprocating saw, bench grinder and belt sander.
Selecting a Grinder
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I realized just how dependant on that grinder I had become when, after six or seven years of punishing abuse and misuse, it finally died on me and my project came to a screeching halt. So I headed down to the local Orchard Supply Hardware store to replace it, where I purchased another 4” Makita angle grinder. It was on sale for $50 (from $60) and it came with a storage case and a five grinding discs.
Although I didn’t have many complaints about the power-output of my last grinder, the motor in the new grinder is rated at 6 amps (the old one was only 5) and it has a metal bearing case with an integrated spindle-lock to make switching discs easier. The only real criticism I can offer is that I would like to see Makita revise/improve their on/off switch. The exposed switch on the side of the Makita grinder is too easy to turn on accidentally, like when the grinder is kicked around on the shop floor. Milwaukee grinders feature a paddle-style on/off switch that I think is a much better design.
Milwaukee, DeWalt, Bosch, Metabo and Hitachi also make angle grinders, but I can’t comment on their performance or durability. The motors in a few of the better 4 1/2” angle grinders are quite a bit more powerful than the 4” Makita, but they are also considerably larger, heavier (up to 6.5lbs compared to the 3.1lb Makita) and more expensive (up to $150 compared to the $50 Makita).
Safety & Accessories
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If there is anything in this picture that you are not familiar with, READ THIS. I’d recommend purchasing a face shield because safety glasses won’t protect your face from flying metal chips, sparks or a fractured cutoff wheel. Notice there are two face shields pictured: one is low profile and fits close to the operator’s face (1). The wider face shied (2) allows the operator to wear a respirator beneath it. I like to wear a dust mask (6) most of the time to avoid breathing abrasive dust and I switch to the respirator (4) when I have to grind through anything that might be harmful to breathe. Consider wearing a pair of safety glasses or goggles (not pictured) in addition to the face shield. Face shields are great for deflecting straight shots, but some metal shavings and sparks will inevitably find their way past that first defense. I also wear a welding cap (5) because I really hate picking hot metal out of my scalp (a backwards baseball cap will work just as well). Hearing loss can occur at sustained noise levels over 75 decibels and an average angle grinder registers closer to 100 decibels. I prefer to use disposable foam or reusable rubber earplugs (7). As far as gloves are concerned, I’ve gotten in the habit of leaving a pair near any tool or project where I’m likely to use them. I probably have at 4-5 pairs of different types of gloves floating around my garage at any given time. A thin pair of leather gardening gloves (8) work well for light fabrication and anything that requires a little dexterity but they aren’t very durable (notice the duct tape). Handling gloves (9) are inexpensive and sturdy, but the material on the back of the fingers will burn though (as shown). A cheap pair or welding gloves (10) costs less than $10 and although tools can be difficult to manipulate, I wear these gloves most often when I’m grinding. They allow me to handle hotter metal than I could otherwise and I’ve had a few minor grinder-related injuries (cuts), but I’ve avoided a few more because of the leather barrier these gloves provided. I only put a pair of kneepads (3) in this picture because it seems like whenever I’m using a grinder I’m crawling around on the shop floor and cold concrete can drain the fun out of anything.
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Try to wear something with long sleeves (preferably 100% cotton) if you’re going to be doing anything more than light grinding. Otherwise sparks will tend to burn your forearms and the healing sores will make you look like a strung-out heroin addict. Most mechanic’s jumpsuits are made to be oil/stain-resistant and the synthetic material and don’t hold-up to heat very well, as evidenced by the holes in my Dickies jumpsuit.
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Grinding wheels (1 & 5) are useful for removing large amounts of material, they last the longest of any of these wheels and they only cost about $2.50 each. Cutoff wheels (6) come in a variety of thicknesses and they also cost about $2.50 each, but the thinner they are, the shorter their lifespan. There are a few different types of wire wheels (3). This one is a course cup-shaped wire wheel that is useful for removing rust and welding slag, etc. Prices vary, but this one cost about $15. The safety guard (7) is an attachment that will come with every grinder. It’s an important safety feature, but it can really limit the type of cuts you can make. The second hand grip (4) is something that I take on/off my grinder depending on the type of grinding I’m doing.
Projects
Here are some quick examples of the type of work you can do with a grinder.
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Notching rollcage tubes with an angle grinder can be a painfully slow and frustrating process, but like anything, it gets easier with a little practice. Alternating between cutoff wheels, grinding wheels and flap-discs will save a lot of time. I cut this tube freehand with a course grinding wheel and then shaped it to a good fit with a flap disc.
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An angle grinder definitely isn’t the fastest way to fit tubes if a better tube notcher is available, but there are some difficult notches that I wouldn’t know how to accomplish without one. The tube in the image on the left needed to be notched on a bend to fit another bent tube, as shown in the image on the right. I’m not aware of a better way to fit that particular joint.
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I hand-cut, notched and shaped all of the tubing and plates that I used to make the rollcage and body mounts for my CJ7 using my 4” Makita angle grinder and a combination of cut-off wheels, grinding grinding and flap-discs.
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I cut into the firewall on our long-travel Tacoma to provide clearance for 35” tires. I used a thin cutoff wheel to make the rough cuts and then switched to a flap-disc to shape the opening and clean up the edges before welding a patch-panel into place.
This Article was originally published on Off-Road.com January 2006
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