Hello welcome to redox engineering I'm Alan
After making this grinding wheel dresser last week today
I'm talking about back to basics with grinding wheels.
In the UK it's requirement that people who use grinding wheels in industry are trained
in the correct use and fitting of the grinding wheels.
Did you know that nearly half of all accidents involving abrasive wheels
are due to operator error or anunsafe system of work
So be safe in the workshop always use safety glasses when grinding
and a dust mask when necessary I recommend that whatever country you're in
find out more about grinding wheels by going to the UK Health and Safety
Executive website the address will be coming up later in the video
so let's go into the workshop see how we do it.
Most of us in the workshop have a bench
grinder like this this one's a 6 inch diameter grinding wheel bench grinder
one side is the grinding wheel and on the other side it's got a wire brush there
will come a time when you need to replace the wheel or you need a different grade
of wheel and when you come to do that I would advise going on the internet first
and looking at the health and safety executives advice on use of abrasive
wheels there's lots of information in this catalog it's free to download the
only downside is it's 53 pages but if you scan through it on the internet you
can pick up some useful information
grinding wheels come in all different forms shapes and sizes
So you've looked on the internet and you've decided you need a new wheel
which do you choose grinding wheels are made from many different materials
depending on the application. You've got the grey carborundum wheels the green
silicon carbide the pink wheels the white aluminium oxide. So have a look at a
suppliers catalog and decide which material is suitable for the jobs you'll
be grinding the next thing you need to do is check your grinding machine and
see the diameter the width and the bore size you need and most important the
speed rpm or m/s of the machine this wheel was supplied with the grinding
machine it's a carborundum wheel and it shows you the speed on here is 3450 rpm
This is over the speed of the machine so it's suitable for fitting.
The paper washers with a grinding wheel a called blotters
because the paper is thick paper and he's very similar to blotting paper the
label should give you the manufacturer's name the type of machine the wheel can
be fitted to the date the size the type of material the wheels is made out of the maximum
speed of the wheel in meters per second or revs per minute.
Now we come onto the flanges the wheels mounted to the bench grinder using the flanges.
the bore does not transmit any power from the motor to the wheel the flanges
grip the wheel and transmits the power to the wheel
the flanges are mounted on top of the blotter
The idea of the blotter is that it absorbs any irregularities in the wheel surface
and helps to spread the load and the
clamping force evenly over the surface of the wheel on both sides
not all wheels need blotters. This wheel which is a diamond grinding wheel has the
diamonds impregnated on an aluminium back and therefore does not need blotters
Now before we fit the wheel we need to make sure there are no cracks.
so we do a visual check that are no cracks and then we'll do a ring test.
To a ring test a wheel take two screw drivers. What we do is hold the wheel
on the one screw driver loosely and then with the plastic part
just tap the wheel it should ring like that, the same with the smaller wheels
It's ringing if it was a cracked wheel it would sound like this sound a dull sound
This is my machine 8 inch bench grinder two wheels.
One on this side which is the fine wheel which I use for sharpening the lathe tools
This side is a coarse wheel for roughing out
The first thing you put on your flange make sure it's clean.
I've already wiped all this down. Fit your grinding wheel flange.
Then your grinding wheel then the other flange
This machine has a left hand thread on this side.
Because when you put pressure on the wheel you don't want the nut to start coming undone.
and you don't need to tighten it with too much force
just enough clamp the wheel between the flanges.
Turn it if there is any run out it doesn't hit your work rests.
Before you start it replace the guard on the outside.
I've plugged it in and switched the power on at the wall but I haven't started it yet.
I know that side is safe because I've used it before and it's run,
but just having fitted this maybe it's a new wheel and I don't know whether it's safe or not.
I've rang it, it sounds okay I can't see any cracks
So the first thing you do is stand to one side just in case. Switch it on
The next thing I need to do is true that wheel up and what I'm using to do that is
a diamond dresser just rub it across the front the wheel.
You could use a single diamond or a carborundum wheel dressing block or a diamond dressing block.
Now rub it on the wheel it will take some of the wheel off.
Obviously you need safety glasses on and because you're getting a lot of grit coming off
you may even need a a mask.
When you've dressed the surface of the wheel all the way around you need then
to check your rest and make sure it's close to the wheel but not touching and
Now that's truing the wheel up it's not balancing the wheel I've not seen a
bench grinder that you can balance the wheel on because to balance the wheel
you usually have small weights on a special flange that you can adjust
around the diameter of the flange to move the weight into different areas
where needed and you also need a balancing spindle and usually
knife edges to balance it on.
Please do not try to true the wheel up by putting shims under the flanges.
This is dangerous because it shifts the clamping force
to a smaller area of the wheel and could result in the wheel cracking.
Oh well thats it for today don't forget to check out the website
and stay safe in the workshop