On Fri, 16 Sep 2005 18:21:55 +0000 (UTC), in uk.d-i-y you wrote:

Phil Addison wrote:
Any comments appreciated on broken links, typos, punctuation, grammar,
readability, facts, gibberish, content, style etc.


The line about D200 drills wants re-hashing as the first sentence refers
to the end of my comments about C1150 drills and introducing the D200
drills.

Re-hashed now. Should it be "D200" or "D 200", ditto the "C"?

As another poster asked about rotation speeds for drill sizes and feed
rates, I would say that this depends very much on what is being drilled
and by what tool.

So a 3 column table of Material/Diameter/Speed? I can slot in table if
someone provides the content. Meanwhile I have incorporated the basics
of your para above and the two below.

e.g. When drilling very hard steel, it is necessary to make sure that
lots of pressure is applied to the twist drill. On the other hand,
aluminium, copper and brass can be better drilled at a slower feed rate,
but quite a fast rotational speed. Just to complicate things, the angle
of the cutting edge may have to change for soft metals. Twist drills are
usually ground for drilling mild steel

Pin drills (those that have a feed handle to lower the cutter, base
plate to place the drilled item and a variable speed of rotation) will
drill slightly different to a hand held powered drill. The use of a
cutting fluid will change the rules again. It's a complex topic, is
drilling metal :-)

I'm not familiar wit the term Pin Drill. Is it covered by the general
term Pillar Drill as already used in that section?

Just thought of another variable.
When using an electric drill to drill holes, if you only grip the pistol
handle, you will tend to bend the drill. Because the pressure is not
behind the cutter, but at an angle to it, this causes the cutter to
wander away from the intended position of the hole. The way round this,
is to lean the drill body at the opposite angle to the point you want to
drill. This makes the drill bit wander where you want it to drill the
hole. (If anyone doesn't understand that, I will expand on it when the
whisky wears off :-)

Not sure about that one. I use two hands on my drill, one on the trigger
handle to take the weight and (try to) keep the bit vertical, and the
other hand at the back of the drill to apply pressure in line with the
drill axis. Seems a natural grasp to me. I just realised the main point
(that actually is missing in this text) is to centre punch the job
first. There is a technique to this that allows you to pull a slightly
'off' punch mark into the exact desired place.

Perhaps it is time to tap into the knowledge of the group and get the
experts in the various materials to tell you. I know a little of
drilling metal, but nothing about drilling wood etc.

Err... did I mention content? :-)

Thanks for the useful input. drillfaq page updated again - let me know
if I've mucked up your input in the editing. ;-)

Phil
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