Cutting slabs - follow-up.

What a surprise.

Doesn't matter. The thing isn't fit for purpose. This equates to a total refund plus some compensation for the cost of doing the return. On a £35 transaction, something like £5 in cash or vouchers would be reasonable.

That would be a much better proposition. There is a wide range of choice in quality 230mm angle grinders in the £70-80 bracket.

Ah, that's music to Andy's ears :-)

Any 9" grinder should sail through 15 slabs. Sounds like it's naff but, if it's your first grinder, check there isn't a reset button, and that the disc hadn't worked loose

No, I've just been out to the van, and it stinks of burnt electrics from the grinder. It was doing quite well before it stopped, it vibrated a lot at first, but after 3 or 4 slabs it seemed to smooth out a lot, and was doing OK. Even by cheap tool standards, this one is pretty s*it - I was taking it easy with it, no cutting so hard that it was slowing the motor down. Alan.

Not really. Just a predictable outcome.

There was somebody who had the smaller version of one of these a while back where the motor caught on fire and burned his jeans and almost his gonads.

Got a feeling that was Ferm rather than a Clarke, but same principle....

Angle grinders can get quite hot mind you - especially when you fill them with masonry dust, so if you have not got one with a motor rated for continuous running then you probably don't want to be cutting for more than 10 mins at a time without a rest to let it cool.

So it's back to the crappy motors issue then isn't it.....

The poor mechanical performance of cheap routers in terms of results out vs. electric power in is well known - e.g. the 2000W models that deliver substantally less than a 1600W quality product.

All of that lost energy has to go somewhere. I'm surprised that the suppliers haven't claimed that the products keep the user's hands warm in winter.

I would say that a 230mm that can't deliver continuous operation or close to it isn't fit for purpose.

One might buy a 115-125mm model to do small work that likely is in short bursts, but a 230mm one is pretty much going to be destined for heavy work like paving and the like and implicit in that is longer periods of running.

Angle grinders are one of the few tools where the motor runs near full speed all the time so a fan should be able to keep it cool. My cheap angle grinder has been going for years but I don't think I would run it for long without checking how hot it was.

A drill would need a separate fan to cool it if it were being used to drive screws all the time, which some may have? I see some models as saying fan cooled..

Unlike the Lidl jigsaw by the sound of it.

Have you checked that it wasn't something as simple as a blown fuse?

probably not, I think Ferm are manufactured in Holland,

Well either that, or cooling arrangements, or probably (in this case) a defective grinder in the first place.

The mechanical output of even decent tools will often be a little over half the electrical input power, so a 2kW grinder will probably need to dissipate at about 1kW in order to keep cool. That is quite a rate of loss.

DeWalt usually publish both figures for their tools which makes for interesting reading sometimes:

It could at least make the tea!

Much depends on the nature of the work. Cutting most masonry items will usually by its nature be an intermittent operation, unless you are cutting a long run of slabs in situ. You are probably at most risk of overheating it when grinding or wire brushing etc.

It is probably worth mentioning that the grinder in this case was probably just faulty in the first place. Another example of the same might well cope fine, since the endurance of this one seems unrealistically poor even for a budget one. Grinders do have the advantage of getting fan cooling at near full speed for all of their operation.

If you look at the Axminster budget (white) grinders, they get designated as "trade" (as opposed to "industrial" for the branded ones) which suggests reasonably intensive use ought to be acceptable.

Also it's very easy to cover the motor ventilation openings with one or both hands, more so if one is not used to the machine.

Or the user not reading the instructions and using something continuously that isn't rated for it.

MBQ

You make an interesting point there, now I've been using angle grinders for many years but the one thing I refuse to do is wear gloves when doing so (I don't consider I have full grip and thus control if I do so, also many on/off switches are not easily operable), I've often had the motors get rather hot but I've never burnt-out any but colleagues who do wear gloves have burnt out angle grinders...

Hi,

I've got one exactly like this, the 'plugs' on the side can be unscrewed to check/replace the brushes, and look at the commutator.

Maybe the brushes have been worn down by cement dust, or if it has a 'soft-start' it's easy to stall on start up which can damage the commutator.

I've used mine to cut through concrete kerbstones using a 'turbowave' disc, though I used wet cutting with a water jet so there was no dust all.

cheers, Pete.

Mine has sometimes clogged up with dust and a quick blast with compressed air has got it working again. I always use a diamond disc for slabs etc.

The marketing organisation is...

Poor outcome whichever

Then it comes back to fitness for purpose. If the thing is going to overheat, it should in any case have some kind of cutout that resets when it cools

Well exactly. The Didldi jigsaws would be far from being able to provide a predictable result.