What are some of the common uses for an angle grinder to the average
Is is good for use to sharpen mower blades ?
I see they commonly have 4 1/4 inch and 7 inch sizes. Is there any
common reason why one is generally better than the other ?
Thanks for any comments or advice !!
Smoothing sharp or rough edges on metal things.
Cutting off rusted or rounded off nuts and bolts.
Cutting and/or shaping a few ceramic tiles (Using a "masonry" disk.)
Cutting almost any hard material in a place where you can't fit other tools.
4-1/2 is big enough for pretty much everyone.
Tim the Toolman Taylor may need the 7" grinder, but few people do!
The smaller grinder is much easier to handle. I would not get a larger one
unless you plan on opening a welding shop!
These are all super replies, and I thank you all very much !! I am sure
the 4 inch one will be fine for me. They sure seem like a handy tool to
have in an average home workshop !
Thanks again !!
I needed to cut up an old hospital bed frame and some other old steel stuff
to fit into a trash barrel and Home Deppot had a sale on angle grinders
and were out of stock I bought their bottom dollar 4 or 4.5 angle
grinder on recommendation of the sales clerk who picked out the cut wheels
too .. Real helpful knowledgeable guy, knew all about angle grinders.
He wasn't there when I went back an hour or so later to buy a dozen or so of
these quickly exploding cutting blades and I found a skinny one that lasts
darn near forever, cuts lickity split too. Figured out he had sold me
grinding wheels and boy are they dangerous when used to cut through hard
stuff at high rpm. Might want to be careful with those things until you
figure them out !
While an angle grinder is handy for some things I would not use one for
sharpening a lawn mower. For this task I would suggest a bench grinder.
This would be much easier to get a good edge and you need to balance the
blade after sharpening anyway, (Or risk buggering up your bearing or shaft
on the motor.) so sharpening the blade on the mower is not really a good
If you did want to sharpen a mower blade with an angle grinder, secure the
blade in a vise and try to maintain the proper angle on the grind. Or just
rough it in and finish with a file.
About the time I had mastered getting the toothpaste back in the tube, then
I have been sharpening mower blades with a 4-1/2" angle grinder for years.
Clamp the blade in a vice and go for it. When I am done the blade looks like
it was done on a machine. With very little practice you can do a very nice
job sharpening a mower blade with an angle grinder.
Remember, we are gutting grass here, this is not some high tech sharpening
job. No need for a razor blade edge, after ten minutes in the grass the
blade is some what dull already.
Get a blade balancer and you are set.
CAVEAT (caps intentional)
Caveat means warning!
I have welded since 1974. One of the most hazardous tools I have ever seen
is a right angle grinder. And I mean ANY angle grinder, even a small die
grinder. A lot of them spin in the 14,000 rpm range, and any time you get
something spinning that fast a lot can happen.
Materials can fly off. Either particles of the wheel, pieces of metal that
are removed, pieces of wire brush, lots of nasty things flying at a high
The tool can "kick", that is, if you put the wheel onto the workpiece at the
wrong angle or direction, the tool can fly back at you with incredible
force. Or, the workpiece can go flying the other direction.
These little boogers are as nasty as a badger, and anyone who knows what a
badger is like understands that statement. For those who don't know what a
badger is, imagine wrestling with a chain saw. They will eat you up and
spit out small pieces. You will lose ....... it will win. EVERY time.
If you are new to operating one of these, pay very strict attention to how
you place the wheel on the work, particularly when using wire brush wheels,
as they tend to grab more than a solid wheel. Imagine you are holding the
tool with the wheel down, and the wheel is a clock. The end of the tool
with the cord coming out of it is toward you. The end with the wheel is
away from you. Almost all of the work should take place between 11:30
position and 12:30 position where you want to touch the work. When the
revolving part of the tool contacts the workpiece in any other part of the
clock, the likelihood of a kick increases. As your experience and skill
goes up and you get the hang of it, you can to to the other positions of the
clock, but start there. Understand what causes a kick or what causes the
workpiece to be spit out, and adjust your contact point accordingly.
Use the handle provided until you learn the behavior of this little beast.
It is advisable but not necessary to use gloves, and I like light ones where
I can hold the grinder tightly. EYE PROTECTION IS A MUST. If you use the
wire brushes, you will normally be picking pieces of wire out of your face
and other exposed body parts. PROTECT YOUR EYES AT ALL TIMES. I'll say
that again. PROTECT YOUR EYES AT ALL TIMES.
The angle grinder can do amazing things. It can also cut off a finger in a
flash before you really master the thing. It can catch your clothing, and
wind you up in a ball in an instant. I have had scores of incidents in
hundreds of hours of using this tool, none of them really major. Bruises,
some lost hide, but nothing really bad. I have heard some really really bad
stories, though, and believe every one of them. These are nasty mean little
bastards, and they don't fight fair.
This thing has a learning curve, so go slow.
Excellent post !!!
I would add that if you get the grinder caught and it jumps........stop it
and check to see if the disk cracked or if a chunk is missing.
If it is cracked or missing a piece......take it off and THROW IT AWAY !!!
Install a new disk and try again.
One of the most hazardous tools I have ever seen is a right angle grinder.
And thank YOU for your VERY good post on a most important point I totally
missed. Angle grinders have a lot of things to consider.
I buy my small grinding wheels at HF. The ones they have for 99 cents work
as good for me as those expensive Makita ones. But when it comes to wire
wheels, I spend the bucks and get Makitas.
IMPORTANT- The older and more worn a wire wheel is, the more wire shards it
spits out. When the wires get worn about half down on a cup knot brush,
toss it. When the wires get about a third worn down on a straight wire
brush, toss it. I have pulled more wires out of my face, hands, arms, and
shirt than I can count. I have even found them embedded in tarps and
drywall close to where I was working.
As an added caveat to your post, I like to lay my grinder on its back or
side, and not down on the wheel. They are easy to crack, and the pieces go
This is a great follow up on the hazards. I purchased an angle
grinder a few months ago. Although I do not use it frequently, I do
find it valuable, especially for cut off work. However, I do consider
it one of my more dangerous power hand tools, and always use it with
a "think twice" respect. Your post does a great job of bringing out
some of the hazards I have already recognized, and a couple I have
Radio Control Aircraft/Paintball Physics/Paintball for 40+
That it does, and a very appropriate warning as well. But I'm glad I
didn't read it before I first used an angle grinder as a kid. :)
Would've probably scared me so bad I never would have! I had watched
the mechanic sharpen the blades on my 6ft john deere belly mower a
couple of times, and then one time he was busy so he asked if I thought
I could do it. I've always been quick to learn, so I said sure. He
told me where he kept his 11" grinder, pointed out some goggles, and let
me go. I noticed later he was keeping a pretty good eye out. Thanks
Matt! You taught me a lot. (That pneumatic grease gun sure spoiled me. :)
In a way, other than wearing me out, I think the big, huge grinder was
safer than the little 4" I have now. The 11" had enough weight it
wasn't going to go flying around, and the spinning parts were heavy
enough that they didn't want to stop with a little nick (3 x 26" blades
on that belly mower tended to be like cutting grass with the sharp edge
of a baseball bat... except for the first hour or two after sharpening).
Warning left intact:
Wanted: Omnibook 800 & accessories, cheap, working or not
sdbuse1 on mailhost bigfoot.com
there is probably a better tool for sharpening mower blades
more detail can be accessed with a smaller diameter grinding wheel
a larger grinding wheel (on an angle grinder with higher amp rating/more
powerful motor) would cover more area faster than a smaller grinding wheel
those with higher amp ratings generally should be able to drive a larger
grinding wheel (higher amp rating = more powerful motor)
a 4" grinder has draws enough amps to run a 4" grinding wheel, but not
enough to run a 7" grinding wheel properly over time
a 7" grinder can run a 7" grinding wheel, or if it can be attached, a 4"
The two or three times I've used an angle grinder, the one was to remove
wood from the bottom of a door. I know a jack plane was the right tool. I do
have one, and used it. but it doesn't plane the end grain very well. A belt
sander is the correct tool, bu I don't own one. So, the angle grinder came
out of the box. Use light pressure, adn keep the wheel moving, cause
otherwise it smokes.
The other was when I was trying to get my trailer to hitch to the ball on
the van. Well, the safety cables wouldn't go into the holes in the bumper.
too small of hooks. So, I used the angle grinder to remove some metal.
I plan to use the angle grinder some time next summer. My church has a girls
camp, which has a barn. The barn has several posts with big bolts sticking
through. The plan is to crank down the bolts good and tight. Take the excess
bolt off with a sawzall, and then smooth it out with Mr. Angle Grinder.
I think I paid $15 for mine from Harbor Fright, and worth every penny.
Christopher A. Young
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