Angle Grinder Speeds

["Clive Murray-White" <clivemw@xxxxxxxxxxxxxxx>]

Dear Linda,

I've used several diamond cutting discs over time but actually find that the
standard  masonry cut off wheels actually do a quicker job. My personal
feeling is that it's got a lot to do with technique and yes I do use a range
of hard marbles.

I'd even go as far as saying that I haven't noticed any appreciable
difference in the speed at which I can remove unwanted material based on the
hardness of the stone.

For what its worth this what I do.

For real fast removal of lots of material I use the big 9inch angle grinder
+ standard fibre cut-off disc; I cut what I call fins, rows of cuts approx 2
cms apart and a comfortable depth, by this I mean that there seems to be a
depth at which any disc doesn't seem to really be enjoying itself and starts
to struggle a bit, probably about 5 cms. Once I've cut a row of these "fins"
I simply tap from the top to the bottom either with a hammer, hammer and
point or if I'm feeling like I'm in a real hurry air chisel. Then repeat and
repeat 'til you get rid of what you don't want. Wear good gloves when you do
this because it is very easy to scrape your knuckles on the rough and sharp
stone.

Of course there is hardly anybody on earth that could do this all day
without being totally exhausted and aching all over, to get round this I
hang the angle grinder from one of my cranes, cut a fin, lower it a bit,
repeat and so on, this means that I never take the full weight of the big
grinder. note: its a good idea to dream up a way to make sure that you don't
have lengths of chain hanging around near the grinder!!!!

I've found that I can cut up to three fins without lowering the crane.

Last point:

Mental outlook has quite a bit to with this as I learned when I launched
into a 12 ton block some years ago. This was before I though of hanging the
grinder. I think the thought of spending days and days doing this kind of
work got the better of me to the point that I was dreading it so I attacked
the stone as if was a serious enemy, this made it all much worse from a
mental point of view.

Staggered out of the studio on the first day feeling as if I had hardly
accomplished anything at all and feeling as if I'd taken on something that
was a bit beyond me, to soothe my aching bones and almost totally numb hands
I took a nice long bath.

And had a good think about it........and came up with hanging the
grinder...........and something else that was probably far more
useful....get rid of the idea that this stone was my enemy..........develop
a comfortable work rhythm....allow myself to thoroughly enjoy the outcomes
of this methodical, mindless and repetitive activity.

I put all this into practice the next day, pretty pleased with the first
effort but found that my crane idea needed a few minor modifications etc,
after a very short while the rhythm kicks in: cut, cut, cut lower the
grinder, cut, cut, cut, and repeat, after about 20 cuts off come the
goggles, ear protection and face mask, tap, tap, tap and huge quantity of
material falls to the floor and instead of it being a miserable job it had
suddenly turned into something very rewarding indeed.

Of course the fin system works with a small grinder and you don't need to
hang it!

But remember the old rules always works best , plan first, cut away the
biggest waste sections with the biggest bit of equipment that you've got,
(since the angle grinder method I've built a saw that can cut over 3ft at a
time, it's pretty slow but once its set up and going I can go off and do
other things) I can hear some people suggesting drilling and splitting but I
prefer cutting, more accurate, fewer accidents. Once the very big cuts have
been made I go to the big angle grinder, then to the 5 inch angle grinder
and then out with the chisels etc.

Angle grinders produce an awful amount of dust and noise and can be pretty
anti-social if you have to work anywhere near other people!

Regards Clive