Angle Grinder Tips For Beginners, Disc Sizes And RPM

When you buy your first angle grinder you need first of all to go through the manual.

So that you can avoid making mistakes in the future.

Mistakes that may hurt you, others or most importantly your pocket.

The grinder has four main parts at the front over here.

This is the spindle, this is what rotates. This is the disc guard.

So on my grinder there's this little bump* that you have to

align with this notch over there.

And then you just tighten it with a screwdriver.

Like that.

When I check my user manual over here, I can see that the disc size

required for my grinder is 115 millimeters with an M14 nut.

But my disc over here does not have a nut.

But this has a maximum diameter of 115 mm.

So this is the right size disc for this grinder.

Here we have two items.

This is what is called a disc clamping nut and this is a backing washer.

On my grinder the backing washer has these two slots that you have to align

to the spindle over. You can see that slot.

You should place it like that. Don't place it opposite

because this must match.

And then you place your disc

and then your disc clamping nut.

You already know you need to press this button then you take your wrench

and you tighten it and it's ready to go.

So this disc over here

is 115 X 2 X 22.2

The second 2 denotes the thickness.

This is much thinner so this is a cutting disk.

If it was a grinding disc it would be much thicker.

And the rest of the numbers over here

22.2 denotes the inner diameter

where you place it on the backing washer.

The same goes here, this is 22.23 mm

which is the inner diameter.

This disc damaged over here so it's not safe to use damaged discs

so the best thing you do just break them in two.

So that you can prevent an accident in the future.

The next thing I'm going to tackle is the flap disc.

This is what is known as a flap disc

A flap disc is just a disc with sandpaper that is glued on it.

You can see the glue over here.

Over here you can also see that

this has a maximum diameter of 115 mm

and this does not have the thickness dimensions

but it also has 22.23 mm as the inner diameter

that fits perfectly over there.

The other thing you need to know about grinding and cutting discs

is that they usually have an expiry date

that's printed on the disk over here

This one will expire in August 2019 so I have like

three more months to use this disc.

The damaged disc over here was to expire in 2020

so I would have had much time to use it.

Another thing you should know about flap discs is that because this is sandpaper

it usually comes with grades.

This has a number 80 written over here

so this is an 80 grit sandpaper.

The higher the number the smoother and more finer grains on sandpaper are.

Because you know sandpaper is just sand that is glued to a paper.

This is 120 grit sandpaper and it's much smoother

you can even bend it like this and nothing will happen.

This is 60 grit sandpaper and it's much coarse

and if you try to bend it too much you are going to break it.

You can see the seams over here.

So the higher the number the smoother the sandpaper becomes

and the lower the number the rougher it is. And the much bigger the grains are.

So when go to buy your flap disc

just check the number. So this is 80 grit sandpaper

This is great for paint removal because I want to do some paint removal somewhere and apply a new coat.

It is also god for rust removal but if I need to do some welding in the future

this is what I'm going to use to clean up the welds.

This in combination with this but this will do best.

This is what is called a wire cup brush

A wire cup brush usually just screws on top like that.

Just need to remove the backing washer and the locking nut.

Just screw it because this is a nut.

If we check from our manual the spindle accepts an M14 nut.

This is an M14 spindle and this is an M14 nut.

Written over there M14.

Just screw it over there like that

and you are ready to go.

So one more important safety thing.

I have another disc over here.

Make sure use gloves when you do these kind of jobs.

I have another wire cup brush over here. This is also an M14 nut.

It fits over here perfectly

but this is not recommended to use over here because

there's something else you need to know and that's the speed.

This wire cup brush has a maximum speed of 8,500 rpm

and this is for a bigger grinder because bigger grinders usually have lower speeds.

Our grinder over here has....

I've already ready cut myself.

Our grinder over here has a maximum speed of 11,500 rpm

This over here has a maximum speed of 12,500 rpm

So this is safe to use on my grinder.

The flap disc has a maximum speed of 13,300 rpm

so this is also safe to use on this grinder.

And our cutting disc over here has a maximum speed of 13,290 rpm

so this is also safe to use here.

Remember safety is the number one priority

Be safe.

Thanks for watching. I hope you learned something new today

and goodbye.

One more last thing it's very crucial that you use gloves for your hands

eye protection and the best eye protection can use is a full face guard

because these metal filings over here usually come flying out.

Same goes for this.

Even if you are using the flap disc or cutting discs there's metal filings

that usually comes flying out.

And it can take out your eye or someone else's eye.

It can pierce your skin. So use full protection.

Use leather gloves as well as a full face guard.