Angle grinder - 9 inch or 4 1/2 inch?

[ELL]

So, I am buying an angle grinder today or tomorrow. I will be using it to cut mild steel 3mm to 10mm - every day, so about 4 hours use per week. Also, I will be putting bevels in mild with it, and grinding rust and other dirt off mild with it.
I have seen that 9 inch grinders are much more powerful but obviously less easy to work with than 115mm grinders - obviously more heavy, can't get into the smaller spaces.
Would it be worth getting a 9 inch grinder for the power and putting 115mm discs in it? Or is this dangerous or pointless?
Also, do you get what you pay for with grinders? I have seen a black and decker with a few discs for 30 quid, and a makita for 50 with no discs. - both 115 mm though.
Thanks.

 

[123hotchef]

a 9" will make your tire very quickly and no 115mm disc in a 9 inch will probably not cut a thing as it will be too small to reach the work. The makita ones are great. Not sure about the B+D. there are also 5"

 

[ELL]

a 9" will make your tire very quickly and no 115mm disc in a 9 inch will probably not cut a thing as it will be too small to reach the work. The makita ones are great. Not sure about the B+D. there are also 5"

Thanks. Good info there.

 

[Wozzaaah]

When a 9" disc wears down to 4 1/2" it does not become dangerous.
You won't get much use out of a 4 1/2" disc though, it will soon become useless due to the larger grinder body.
If you are cutting 10mm steel then you'll get through a lot of 4 1/2" discs, it sounds like you really need both.

 

[hotponyshoes]

2 completely different tools to use.
So different I would say get both.
Either makita or metabo (I think) have a deal on where you buy a 9" and get a 4.5" free.

A 150mm grinder is a good compromise if you only want one. But, they are more expensive and you'll probably only find the discs online.

You do get what you pay for.
Although I think even the lidl ones have a 3yr warranty.

Dewalt have power and last well for the price.
Metabo or bosch (with a paddle switch) are quality and nice to use.

 

[tigdlo]

5" are also worth a look, you can always use 4.5" discs if you get a good deal on consumables as they are a similar rpm, 9" grinders are a bit slow for 4.5" diameter. Lidl cutting discs are 5" and OK for the money, I use them now I don't do much work and ebay bargains are also non existant.

 

[Shedendman]

Get yourself one of these

MAKITA GA5040C 240v Angle grinder 5" (125mm) 88381629140 | eBay

Wheel guard cover. No load speed: 2800 - 11000rpm. Warranty info.

www.ebay.co.uk

Yes its 5'',BUT,its variable speed,also takes the 115mm discs,plus not as heavy as a 9'',you'll get away with a 150mm grinding disc on it also
I've had mine 5yrs now,it takes a battering at times but its bomb proof

 

[Onoff]

Ask SWMBO

 

[dieselsamurai]

I always try to avoid using the 9" unless i really have no choice a 5" is a good compromise but unless you get a petrol saw which are much safer in my opinion cutting 10mm with an 115mm angle grinder will get tedious very quickly

depends on your budget but if this is for profit the a Plasma cutter will pay for itself in time spent saved in very short time

 

[Erie Fred]

A 9" grinder will run a 4 1/2" wheel too slow.

 

[sako243]

Both, I picked up a Hitachi 9" and 4.5" from Toolstation a few years back. They've been abused and still going strong.

Mind you when I want to cut throug thicker stuff I must admit to using the big petrol one, so much faster.

 

[Kram]

Could I suggest you consider a 3" grinder. Due to the much smaller mounting nut you actually get more usable cutting depth than 115mm, much more manouverable and comfortable to use. A decent brushless one will have decent power. I have a cheapy Lidl 12v one which is really only light duty but impressive compared to its larger 115mm 20v brother, and I much prefer it.

The disadvantage is, discs are only available online, which I find odd as, the big brands do sell 3" grinders!

Plasma is also very quick and certainally a good idea if suitable, either using a guide or freehand. Freehand I have to cut oversize and clean up with grinder.

 

[bricol]

I would say it depends on what you are cutting.

10mm round bar is a lot easier on the discs and tools than 1000mm long cut through 3mm.

If its flat bar, a chop saw might be better. If its long lengths, a plasma as others have said.

Angle grinders don't really like long periods of hard work - the motors and especially the gearboxes get hot very quickly, even when you make a deliberate effort to let the disc do the work and not force it.

 

[addjunkie]

Any premium brand, mains powered 115 grinder will be ideal…..

 

[gaz1]

get a plasma cutter for up to 5mm or more your choice there handy and get really close to where you want

as goes for the grinders they have there uses bot both do come in handy

 

[Barking Mat]

Big grinders are only for big stuff in my books and they can kick.

Small grinder, all day, for cutting 10mm steel, thin disk.

Ten mm steel plate ? Plasma or gas cutting gear.

 

[zzr1200]

Both....Sorted....110 or 240v

Angle Grinders | Alan Wadkins Toolstore

Shop an extensive range of Angle Grinders from Alan Wadkins Toolstore. Next day delivery available on items over £25.

www.alanwadkinstoolstore.co.uk

PS.. A plasma cutter would be my choice...

 

[Bornfree]

Buy a 9" with a thin disc they slice through 3mm like butter. I use a 9" far more than my 4.5 and 5" grinders.

 

[Hood]

9 inch grinder all day long for what you are intending doing. I see people pi$$ing about trying to cut stuff up with 4.5" grinders and just shake my head
Best is to get both as the 4.5" do have their place but to me it is not cutting stuff up unless it is a small cut or you have to hold the material with one hand whilst you cut with the other.
You often get deals where you get a 9" and a 4.5" in a package.

 

[CompoSimmonite]

I've got 9" and several 4.5". The smaller get the most use