angle grinder advise please

[monkey boy]

i want to bye my first angle grinder, iv seen them for sale really cheap. what i want to know is , can any disk fit on any grinder or does it have to be the same make?

il be very grateful for any help
monkey boy

 

[Sniper]

They're pretty standard fitting so most discs for a 4" will fit most hand grinders. Make sure you get the right discs for the job you are doing with it. You get grinding discs and cutting discs and you really should not use them for what they are not built for. As a general rule cutting discs are thinner than grinding discs but the packaging will tell you which is which, and remember to keep them seperate.

 

[demographic]

i want to bye my first angle grinder, iv seen them for sale really cheap. what i want to know is , can any disk fit on any grinder or does it have to be the same make?

il be very grateful for any help
monkey boy

As long as the external diamater is the same I've not noticed any other reasons why theres any problems.
Have just gone into a shop and bought that right diamater and used it.

Just make sure youre not using disks that are usually used in a petrol cut off saw in a electric grinder as they can be rated for different RPMs and you don't want them to come apart because they are spinning too fast.

Then again, I have had to read through tha abrasive discs regulations whilst on a welding course and theres a fair bit to it so its not all safe as houses, take care with them.

 

[ForgeCorvus]

Remember there are two sizes of mini angle grinders
4 inch (whatever that is in metric), they normally have a 3/8 thread (10mm).
Or 4 1/2 inch (which according to mine is 415mm) normally 1/2 thread (I think)
The disks aren't interchangable as the holes in the middle are different sizes (the larger hole can fit on the smaller spindle, but its really risky, just don't do it)

Angle grinders are dangerous, mine spins a disk at 11000 rpm that will eat concrete*, steel or wood** like its not there

You can get really cheap 4 inch ones (I've seen them down to £13), but they aren't exactly durable (you really do get what you pay for) and they tend to be gutless

I use a 4 1/2 made by Agojama (no, I hadn't heard of them either) thats done an awful lot of work and is still sound.
Black & Wrecker (the Pro range) seem to last forever, not really used any other makes

If you can choose between two grinders of the same size, buy the one with the highest Watts

If you're using the cutting disks (the 1/8 thick ones) try to buy the flat type rather then the ones with a dome moulded in the middle as they seem to me to be less likely to fail.

Grinding disks can be flat or domed (domed is easier to use as the steel nut is kept away for the surface of the work)

Take care not to over tighten the nut when changing the disks, as you could weaken the disk.
I don't use either the spindle spanner or the spindle lock when putting a disk on I just hold the disk in my fingers (the disk spins in the direction to tighten the nut anyway)

Don't forget to unplug before changing disks, grinders are designed to chew things that are much tougher then meat


*Stone cutting disks are available
**I used to make self-nocked arrows for re-enactors using a cutting disk and going very carefully

 

[johnnytheboy]

If you can avoid the 4" ones they are old school, getting discs for them etc is getting harder, get the 4.5" 115mm one discs are cheaper and more readily available.

 

[helixpteron]

Perhaps consider the use of impact resistant specs' or goggles and strong gloves when starting out using an angle grinder.

They're so much easier to replace than eyes and fingers.........

 

[RAPPLEBY2000]

another grinder question..

For a while i used the "old school" method my dad taught me (a drill clamped to a bench with a grinder adaptor)...
untill in a second I saw the disk fly off do a couple of hundred skids on the worktop then roll/fly past me...
since watching a documentary when a chap practically cut himself in half with a grinder I would like to be a lot safer!: I quite like living!

what are the fors/againsts for a bench grinder rather than a handheld one?
the jobs i do often are:
tool sharpening(from blunt)
cutting large sheet metal/pipes
using it to remove rough areas on metal(like a file would).
(90% of my metal work is done indoors)
any advice welcome cheers

 

[johnboy]

another grinder question..
what are the fors/againsts for a bench grinder rather than a handheld one?

A Bench Mounted Grinder ( off hand grinder) and an Angle grinder are 2 diferent tools that use the same method for workpiece material removal.

A Bench mounted Grinder is useful for workshop stuff such as: tool sharpening, linishing, deburring etc .

Generally you dont use them for cutting though pipes and metal sheet.

An angle grinder by it's nature is portable and used for a variety of tasks from cutting to grinding down welds rust / scale removal.


Hope this helps....

Cheers

John

 

[FGYT]

for cuting you can get thin discs that are 1.5mm (even 1mm called slitting discs i think good for Stainless steel trim ) insetad of the normal 3mm cutting discs
These use less force and less heat to cut as your removing 1/2 the metal for the same job these are what i use to cut out knife blanks

you get stone and metal cutting discs in 3mm thick they will cut each others material but will wear out faster these only cut on the edge like a circular saw

the thick discs 5-6mm normally domed are grinding discs these cut on the face like a sanding disc

generally you get what you pay for i buy reasonable quality not the cheapest


you can get other usfull heads like a sanding plate or a flat wheel plate good for finer finishing (finer than grinding disc)
wire brush heads are usfull for rust removal or texturing wood
even a disc with a chainsaw type blade fixed round the edge for wood carving
Diamond disc are relativley cheap and a good bet if you cut a lot of stone or conctere stuff usfull for chasing into walls or cutting tiles


ATB

Duncan

 

[demographic]

for cuting you can get thin discs that are 1.5mm (even 1mm called slitting discs i think good for Stainless steel trim ) insetad of the normal 3mm cutting discs
These use less force and less heat to cut as your removing 1/2 the metal for the same job these are what i use to cut out knife blanks

you get stone and metal cutting discs in 3mm thick they will cut each others material but will wear out faster these only cut on the edge like a circular saw

the thick discs 5-6mm normally domed are grinding discs these cut on the face like a sanding disc

generally you get what you pay for i buy reasonable quality not the cheapest


you can get other usfull heads like a sanding plate or a flat wheel plate good for finer finishing (finer than grinding disc)
wire brush heads are usfull for rust removal or texturing wood
even a disc with a chainsaw type blade fixed round the edge for wood carving
Diamond disc are relativley cheap and a good bet if you cut a lot of stone or conctere stuff usfull for chasing into walls or cutting tiles


ATB

Duncan

I prefer those really thin cutting discs as well, they are way faster than the 3mm ones but even less able to handle side loadings, now i know you shouldn't grind with a cutting disc anyway but sometimes even cutting round a shape can impose side loadings on them.

I still use them, but am just more carefull with them.

 

[Matt.S]

I don't think it's been said but even if it has it's worth repeating: don't buy the dirt-cheap disks by an unheard of company and don't use a disk that's taken a hard knock or appears damaged. The outside edge of that thing will be going about 180 MPH and at that speed if it comes apart... well how familiar are you with shrapnel wounds? When starting-up a new disk point it so the direction of spin is such that if it comes apart it's not going to hit anything important.

Make sure to wear adequate PPE at all times. I use a welding mask (shade flipped up) over close-fitting safety glasses, and usually am completely covered in cotton and leather, including welding gauntlets. This though is mainly to provide some protection against power brush wires and sparks; short of plate armour there's not much going to stop a grinder disk removing large pieces of your body if you let it slip. If you're doing much grinding indoors I would suggest some ear protection too; hearing damage occurs a lot easier than most people think and is often permanent. Watch where the spark stream goes too, for obvious reasons.

I find angle grinders very useful tools but they have a lot of power and must be treated with a proper respect, just like any potentially dangerous thing.

 

[ForgeCorvus]

Basically treat an angle grinder with the same respect you would a chainsaw

 

[smoggy]

sound advice..........except I don't entirely agree with the reference to cheap grinders.......

It depends if it is to have a hard life, all day everyday.....or be used on the occasional weekend...

I have a cheapish one which gets plenty of DIY use on heavy steel, cutting, grinding and wire brushing every weekend working on the car and it is still going well after 4 years!

If it's for DIY type use then those sold by the likes of lidle/neto/aldi in their regular promotions are a good buy, also the same stores offer some good value attachment packs...discs, brushes and some more unusual types of wheel for other uses.....well worth taking a looksee.

But do heed the advice above and work safe and respect "Mr Angry". Not only can they make a mess of a piece of metal, but they'll not leave a lot of flesh after contact!

Nigel.

 

[monkey boy]

thanx everyone thats bean really helpful.
what disk do you think would be a safe option to make a knife out of a file, as i want to do a good job of it and a safe one aswell.

thanks again