I’m in the market for an angle grinder to make a notch in an existing concrete sidewalk to allow placement of a deck post. I also plan on using the grinder in the future to shape curves in furniture parts and wooden sculptures. Makita has a 12-amp model but most angle grinders appear to be 7-amp models. Is there any reason I or anyone would need a 12-amp angle grinder? Are 4 1/2″ wheels adequate and preferable for most applications? Is a 4 1/2″ angle-grinder the appropriate tool to cut a notch out of a 3″ thick concrete slab?
Thanks,
Lyptus
Replies
Describe this "notch" you have planned.
Deck post? a 4x4? a 2" pipe?
My TREX deck has stairs that fall on a concrete sidewalk. There is about 2†of concrete slab extending on each side of the stair landing. It is not advisable to notch TREX posts so to abut the post to the stairs, I was planning on cutting away the concrete slab to make it flush with the sides of the stairs. I don’t really need a notch- just a means to cut off 2†of width from a 3†thick slab.
Diamond blade in a cicular saw will get you more depth of cut than a 4 1/2" angle grinder. Make a couple of shallow passes increasing the depth of cut with each pass. When you bottom out on the depth, take a hammer and wack the edge of the slab and it will break off fairly clean.
For a one shot job you aren't going to damage the saw.
Blow out the circular saw with an air gun.
Wear eye,and hearing protection , as well as a good respirator.
In fact I've been using my worm drive like that for
over twelve years. Hasn't hurt it yet.
Re. using worm drive for 12 years to cut concrete.
Might be time to buy an electric powered chop saw if you are cutting a lot. Once you use it a few times and get used to it, they are great.
I bought one used years ago and just having it is real nice.
I have not used my circ saw with a diamond blade for 12 years.
I agree it would be a better tool.
The circular saw works fine for those odd
jobs that don't require an actual Demo Saw.
I 'm always trying to avoid carrying another thing around.
Re.
"I'm trying to avoid carrying another tool around"
I am just looking to buy a bigger trailer.
Every day is so wild and different that I need everything.
Today I used both electric and gas powered chop saws till noon.
Then went and ran electrical devices in a bathroom and sweated some stops on the lav supplies and toilet supply.
For what I do, if I had used my circular saw, I would have never gotten to the 2nd job and would be going back to the 1st job again.
Lucky you that you dont cut a lot of concrete.
Oh don't worry I've got to
carry all sorts of toy's too.
I miss the simple day's of just laying stone. Now it's
endless power tools for wood.
No, I generally get by with a 4 1/2" angle grinder and the worm drive.
with an occasional demo saw rental.
What Dave says...
Even for a little cut like you have I'd suggest getting a 10" hand-held hot saw. Either rent or borrow if you know someone that has one.
A 4-1/2" grinder will get you a little more than an inch depth of cut. May be a bit shallow for cutting your notch in the concrete. But a larger grinder would be a PIA to use for, e.g., an engine for an Arbortech.
Rent a saw for the crete, or use a diamond blade in a CS, and get the smaller grinder for general use. I've never had a problem with a grinder being underpowered, for masonry or wood.
Mike Hennessy
Pittsburgh, PA
I like the angle grinder better for concrete cutting than the circular saw, because I find I'm doing more notching and cutting on irregular surfaces, cutting short pieces etc. The shoe on the circular saw can be a hindrance rather than a help if you're not doing long, straight cuts on flat surfaces.
You need a 7" to get a significant depth of cut. You'll want the 4.5" for your furniture work. They're cheap enough that buying two isn't going to break the bank.
I bought a cheap Chinese 7" angle grinder at Princess Auto (Canadian equivalent of Harbor Freight and the like) for $35, and it's cut LOTS of concrete, paving stones, brick etc. along with lots of rebar, steel etc. I figured it would be toast pretty quick considering how much dust it breathes in, but it's still going strong after years of abuse. If you spend too much on one, you'll be hesitant to use it for the rough stuff, which defeats the purpose really.