Need a new SDS drill

[Doctor Drivel]

[Chris Bacon]

Well, you haven't made any answer to my questions in this thread, so either you're going to shortly, or you haven't in this particular case got the faintest idea what you're on about. Reading between the lines, I suspect the latter.

[Grunff]

Chris, the point Dave was making is that the rated input power of a motor does not really tell you all that much about the motor's output - any more than the voltage of a cordless drill tells you about its power.

A cheap 900W motor will often be less torquey than a 600W quality motor (all gearing aside). I have an old Bosch 600W drill. This is a lot, lot more 'powerful', in terms of drilling performance, than the 1080W Performace Power drill I bought (which I use for plaster mixing).

This becomes even more obvious in routers, where you have no gearing to compensate. Just compare a 600W Makita with a 1200W . It won't take you long to see the difference in power output.

Input power is useful for comparing tools from the same manufacturer (a

900W Makita will be more powerful than a 600W Makita), but is considerably less useful in cross-manufacturer comparisons.

[David]

[David]

In article , Doctor Drivel writes

Well you have stated on more than one occasion that your descaler works because you look in your kettle and the scale is no longer there, what test equipment did you use?

[Chris Bacon]

Bear with me, this is becoming tedious. He actually started by saying:

"The power input to a drill means nothing and gives no clue about its performance".

This was changed to:

"It gives some idea, but that's all. With an SDS you're "That's the important figure. But if you do some checking you'll find 900 watt input SDS drills that manage 5J plus".

I then asked the question, about a range of drills, all 900W, producing impact energies of 3.5J, 3.8J, 4J (my Aldi cheapo),

8.5J, and 10J: Which is most "efficient"? Which one cost the best part of £600??

No answer, just some incorrect as well as invalid mumbling about inefficiency, heat, burning out. There wasn't a reference to "torque", this is not about routers, it's about SDS drills.

I know that DP *does* make useful contributions where he knows what he's on about, but this ain't one. Will I get a non-slippery answer? I very much doubt it. Which 900W drill above do *you* think is the most efficient; which one cost nearly £600, compared to my £25 one?

Now we've Mr. Rhumn talking about "brass gears" (now changed to "metal") in electric hand tools, and "brass sleeve bearings", too!

[Grunff]

Honest answer: I think we're getting bogged down in nit-picking. When Dave said "The power input to a drill means nothing and gives no clue about its performance" I knew what he meant - I understood the unwritten constraints which applied to that statement.

I suspect many others did too. It would be like me saying "the bhp output of a car engine tells you nothing about how fast the car is". This statement can only be true if the reader and I share a common set of values, and understanding of what makes a car fast. Taken purely at face value, it's false - a 60bhp car will almost always be slower than a

400bhp car.

[Chris Bacon]

LOL! Coat it with a carborundum-based anti-slip compound to BS999ZZZZZ...

[Chris Bacon]

I dunno what your apparent telepathic link with DP is about, 'cos I don't have one. Do you think that the power input to a drill means nothing and gives no clue about its performance, or do you go with the revision that well, erm, yes, it does, actually.

If you can show me a "400BHP car" that's slower than a 60BHP one, I'd love to see it - can you show me one?

[Grunff]

I think the statement can be correct given a certain set of assumptions

- it's the kind of thing we all say sometimes, when those assumptions are understood.

Ah, but what is meant by slower/faster? Straight line - it's unlikely I could find a 400bhp car that's slower than a 60bhp car (possible, but unlikely). Around a windy track? Easily. Lots of small cars would completely destroy old American stright-line monsters round a track.

[Matt]

Yes.

All the appropriate ones.

[Dave Plowman (News)]

Just use and enjoy your cheap power tools then. I very much suspect you've never used decent ones.

[Dave Plowman (News)]

It certainly is.

Now just let's look at that statement in context. Here is the full post.

******************** From: Dave Plowman (News) Subject: Re: Need a new SDS drill Date: Wed, 19 Oct 2005 11:10 Newsgroups: uk.d-i-y

The power input to a drill means nothing and gives no clue about its performance.

*****************

It was a reply to the usual Drivel thing of simply quoting so called specs without understanding them. The quoted 'wattage' is only there to tell how much power it *consumes*, a legal requirement, but nothing whatsoever to do with the actual performance. Oh - and suggesting that because it looks like a Makita it must be as good.

Because you seemed to have lost the plot. Ask yourself why 'cheap' products like this always consume more power than decent ones. I'll answer that anyway. It's because they have poorly designed motors and cheap to make bearings and gears, etc. Which invariably makes them heavier than necessary.

That's a stupid question. Efficiency (power in against power out) in a mains power tool isn't likely to be a major selling point given just how much energy they actually consume when in use. But there's a lot more to overall efficiency than that and selling price. Otherwise your 600 quid example would simply not sell. And where did you find a mains SDS 4J ish drill at 600 quid? Is it solid gold?

I understood what he was on about. You clearly didn't.

[Chris Bacon]

No they aren't. If one says one thing but means then says another, how is anyone to know what's going on?

[Dave Plowman (News)]

I've got two cars both with near enough the same BHP - 190. Both 5 seat autos. One has a top speed of 128, the other 149. The slower car weighs less and has more peak torque.

[Doctor Drivel]

That is the case. I don't need scientific testing to determine that.

None required. Boy are you dumb.

[Doctor Drivel]

Lord Hall, elaborate please.

Lord Hall, elaborate please.

[Doctor Drivel]

Bzzzzt. Wrong. I have never come across anything from him that is useful. He didn't service his gas boiler for 12 years and advocated that to people here. The man is a senile fool. I just hope no one takes any notice of him.

[Dave Plowman (News)]

Is this the definitive time now? Each and every time you mention this it's different.

And I'm still waiting for *you* to tell us all about 'servicing' a boiler once a year as you seem to think is needed.

Stick to thinking that power input to drills equates to power output.

[Doctor Drivel]

Are these the sort of specs you find in boiler manuals, that say service the boiler every year, not every 12 years?