View Single Post
  #5   Report Post  
John Rumm
 
Posts: n/a
Default

Stefek Zaba wrote:

If anything, I'd drop the more ambitious 'ways in which particular tools
differ' sections at the end (well, the section on jigsaws and the
placeholders for the others) for now. It's a big extra chunk of effort,
and I think you should rest for now ;-) Of course if others want to chip


OK done another bit:

The Drill

We can deal with two types he the mains and the cordless.

Mains Drills

Probably most peoples first DIY tool purchase. Essential for the classic
DIY task of affixing shelves, but also able to make holes in most
materials, sand (quick and rough), grind, polish, polish etc… if you
start looking at all the add on gadgets you can get a drill becomes a
very versatile bit of kit.

Drills in their most basic form are single speed with rotation in one
direction only. These are fine for drilling in wood, and also ok for
many polishing, sanding and grinding operations. The are also pretty
small and hence can be handy for getting into tight spaces like between
joists etc.

Adding things like variable speed and reverse expand the range of tasks
that can be done safely like screw driving, and drilling metals. The
addition of a gearbox with two or three speed ranges also add the
ability to use less speed and more torque for tasks that will benefit.
The other usual addition is that of “hammer” action. Hammer is perhaps
overstating the facility a little, "vibration" might be better! This
gives you some capacity to drill hard stuff like masonry at the expense
of lots of noise.

For big, or deep holes in masonry (especially really hard materials like
concrete or engineering bricks) the recent advent of the SDS drill will
wipe the floor with any hammer drill as well as adding some party tricks
of its own.

The bigger more powerful drills can turn tools like big hole saws, core
bores (for big holes in masonry), and are good at mixing stuff with a
suitable mixing paddle.

For basic operations the budget tools will do pretty much what the high
end ones will. Spending more money will buy you better endurance from
the motor (you can run it longer without rest periods, and it will last
longer), better speed controllers, and more robust gearboxes. Bearings
will improve and become more impervious to dust (handy if you do much
masonry work, or lots of grinding and sanding). If looked after, even a
basic drill should last years (there must be countless 30 year old Black
and Decker drills floating about).

Cordless Drills

The cordless drill is a godsend any time you need a drill and the
freedom from a mains flex. Ideal for screw driving (where the DC motor
will provide a much smoother delivery of power than many mains drills).
If you assemble flat pack furniture then a cordless drill will save many
hours of work!

The spread in performance between budget and high end is very marked in
cordless drills (far more so than with mains drills). The cheaper end of
the market can be pretty disappointing – to the extent that it is often
better looking only at the mid range or up. Remember a good amount of
money will need to be spent on batteries and charger before you are
going to get decent performance.

Two types are readily available, the Drill/Driver and the Combi Drill.
The latter adds a hammer action. The former will be cheaper and in many
cases more than adequate if backed up by a mains or SDS drill for times
that hammer is needed.

Most will have a speed controller, this essential feature when
implemented well, will greatly enhances the usability of the tool. Some
better tools implement a rotor break that will stop the rotation when
you release the trigger. This helps to avoid accidentally driving a
screw too far into the work, stripping threads etc.

Many will have a variable torque limiter. This will allow you to set how
much to tighten a screw. It can make the task of putting in lots of
small screws quick and easy since you can be quite ham fisted with the
trigger, in the knowledge that the drill will back off before you over
do it! With better tools the repeatability of the limiter improves.

Having more than one battery is to be very much recommended. If you have
three and a good charger, then chances are it will keep going all day,
and you will be worn out long before it is!

What type of cordless do I want? If you are talking about a good quality
tool with decent cells then the limits of performance are roughly:

9V will do most do most wood drilling tasks, but will struggle with
bigger spade bits. Hammer action will be a tad feeble but better than
none. Screw driving will start to have difficulties with 4” and bigger
screws into softwood.

12V will get your 4” screw driven home with more authority and better
performance on masonry.

14.4V will deal with pretty much any screw, handle smaller hole saws,
and make a pretty reasonable stab at hammer action.

18V+ will swing a 5” hole saw, mix a bucket of plaster, and stick a 6”
roofing screw into solid wood without any difficulty. It is at this
level you match the power of a smallish mains drill, but with far more
finesse and controllability. However the weight and size is creeping up
so it pays to choose one with a nice balance to it.

If you are looking at the £29.95 18V combi drill special on the back of
your screwstation catalogue then all bets are off, but it might make a
nice dumbbell!



--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/