Following discussions about updating John Schmitt's and Clive Elsmore's
FAQ so it ties in with the recent faq sections on different types of
drills, I have done a tweaked version. Much is the same, but with some
new sections on tile and metal drilling and a couple of extra paragraphs
elswhere.

The original can be found he

http://www.axp.mdx.ac.uk/~john49/drillfaq.htm

The proposed new version he

http://www.internode.co.uk/diyfaq/drillfaq.htm

Comments as usual please.

If you have any additional info to expand the metal drilling section,
then fire away!



--
Cheers,

John.

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On Thu, 01 Sep 2005 03:37:27 +0100, John Rumm
wrote:

Following discussions about updating John Schmitt's and Clive Elsmore's
FAQ so it ties in with the recent faq sections on different types of
drills, I have done a tweaked version. Much is the same, but with some
new sections on tile and metal drilling and a couple of extra paragraphs
elswhere.

Looks good from here.


http://www.internode.co.uk/diyfaq/drillfaq.htm

Comments as usual please.

1 typo alert: In the Stirring section "sow" should be "slow". Spell
checkers are handy but less than perfect. I recieved a flyer from a friend
informing me that he would be "mowing house".

If you have any additional info to expand the metal drilling section,
then fire away!

What about:

Drilling sheet metal into a block of scrap wood (MDF ideal) will result in
a cleaner exit hole and less chance of the metal "climbing" up the flutes
of the drill immediately after breakthrough.



There are also, for those of you intending to do a lot of metal drilling,
coated drills. Normally this is Titanium Aluminium Nitride (TiAlN). This
is a golden colour, but beware, some of the super-cheap ones are simply
flash-plated gold, or even painted gold. The coating is applied by vapour
deposition and is hard, tough and has a low coefficient of friction. High
speed steel drills do not drill aluminium gracefully, as that metal tends
to weld itself to the drill bit, resulting in poor swarf clearance and a
badly toleranced hole, either oversize, out-of-round or both. The use of
paraffin or white spirit helps to an extent for aluminium. With TiAlN the
low coefficient of friction eliminates this, and most metals can be
drilled without coolant/lubricant. On top of this, faster cutting speeds
can be employed and the tool life is about 10 times that of HSS. Obviously
the price is higher, but industry seems to find it cost-effective,
including less interruption for changing the bit. I (JS) went to a
building exhibition some years ago and one of the stands was demonstrating
these bits. The sales man had a pillar drill and on a cycle time of about
once a second drilled through a 10" file until it resembled Swiss cheese.
Very impressive!

Cut and paste at will.

John Schmitt

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John Rumm wrote:
Following discussions about updating John Schmitt's and Clive Elsmore's
FAQ so it ties in with the recent faq sections on different types of
drills, I have done a tweaked version. Much is the same, but with some
new sections on tile and metal drilling and a couple of extra paragraphs
elswhere.

http://www.internode.co.uk/diyfaq/drillfaq.htm

Comments as usual please.

Some just jarred, some are additions.

After "stud finder".
Wiring regulations specify that cables run close to the surface of
plasterboard should be vertical or horizontal, from switches or sockets,
however, in practice this may vary.
(I'm not sure of the exact regulations, but maybe just a sentance along
these lines)
"loud and also", I'd lose the also.

Perhaps after "heating and cracking", "One way of drilling holes in glass
is to add abrasive to this liquid, and use a simple rod or tube as a
drill"
"quite large diameter (150mm) sizes" I'd lose diameter.
"One some" = "On some".
"vital component." Add "If unlucky, broken wrists can be the result,
due to the very high torque".
"sow fixed" = "slow fixed"
"keep it in the chuck" = "tie it securely to the mains flex next to the
plug"
"7Kg" = "7Kg force for a 10mm bit"
"do the work.", add "For smaller bits, reduce this greatly, for a 2mm
bit, under a kilo may be appropriate".

After "rather than the sheds", "Sharp drillbits will need significantly
less power and effort to drill with, this is especially important with
cordless drills as it will prolong battery life.
One useful document on those who want to try sharpening drills can be
found on http://groups.google.com/group/rec.crafts.metalworking/msg/75bf76fcbeca2696?dmode=source"

On Thu, 01 Sep 2005 12:02:07 +0100, Ian Stirling
wrote:


Perhaps after "heating and cracking", "One way of drilling holes in glass
is to add abrasive to this liquid, and use a simple rod or tube as a
drill"

I'd leave out the rod, mention that suitable carborundum powder (typically
60 grit) is available from lapidary suppliers. Also copper is used for the
tube, because it is soft and tends to pick up the abrasive particles, so
that cutting rate is maximised. A pumping action is also important as the
abrasive tends to ooze back up the hole.

"vital component." Add "If unlucky, broken wrists can be the result,
due to the very high torque".

If you are left-handed check that if there is button to lock the trigger
down it does not engage under your finger in normal use.

This is exactly what happened to me. It was only by luck that I got my
hand off a 750w drill when it caught. The drill carried on until it jerked
the plug out of the wall. The drill was an excellent shot; the plug caught
me in the crown jewels. :-#

John Schmitt

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John Schmitt wrote:

I'd leave out the rod, mention that suitable carborundum powder
(typically 60 grit) is available from lapidary suppliers. Also copper
is used for the tube, because it is soft and tends to pick up the
abrasive particles, so that cutting rate is maximised. A pumping action
is also important as the abrasive tends to ooze back up the hole.

Apparently the same "copper and grit" technique is also commonly used
for various deep cut glass engraving techniques according to my (glass
engraver) FIL. A small lathe is used to spin copper wheels of various
types and profiles, and the glase os offered up to them while a mixture
of grit and oil is applied with a finger to the rotating wheel.

This is exactly what happened to me. It was only by luck that I got my
hand off a 750w drill when it caught. The drill carried on until it
jerked the plug out of the wall. The drill was an excellent shot; the
plug caught me in the crown jewels. :-#

Ouch!

I bet there was for a very brief moment a slightly smug expression on
your face that said "ha! got away with it that time!). ;-)

--
Cheers,

John.

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On Thu, 01 Sep 2005 15:27:18 +0100, John Rumm
wrote:

This is exactly what happened to me. It was only by luck that I got my
hand off a 750w drill when it caught. The drill carried on until it
jerked the plug out of the wall. The drill was an excellent shot; the
plug caught me in the crown jewels. :-#

Ouch!

I bet there was for a very brief moment a slightly smug expression on
your face that said "ha! got away with it that time!). ;-)

More like "That was close, Phewoooooooooooh!" doubles up, weeping
silently

John Schmitt

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Ian Stirling wrote:
John Rumm wrote:
Following discussions about updating John Schmitt's and Clive Elsmore's
FAQ so it ties in with the recent faq sections on different types of
drills, I have done a tweaked version. Much is the same, but with some
new sections on tile and metal drilling and a couple of extra paragraphs
elswhere.

http://www.internode.co.uk/diyfaq/drillfaq.htm

Comments as usual please.
snip
One useful document on those who want to try sharpening drills can be
found on http://groups.google.com/group/rec.crafts.metalworking/msg/75bf76fcbeca2696?dmode=source"

However, as I just found myself, after sharpening a poorly performing
drillbit - even the sharpest drills don't work very well backwards...

On Fri, 02 Sep 2005 15:45:34 +0100, Ian Stirling
wrote:


However, as I just found myself, after sharpening a poorly performing
drillbit - even the sharpest drills don't work very well backwards...

Been there, done that, got the t-shirt.

John Schmitt

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in 443703 20050902 155507 "John Schmitt" wrote:
On Fri, 02 Sep 2005 15:45:34 +0100, Ian Stirling
wrote:


However, as I just found myself, after sharpening a poorly performing
drillbit - even the sharpest drills don't work very well backwards...

Neither do chain-saws!

John Rumm wrote:


Comments as usual please.

Great as usual. Additions - drills stands? And the use of Cobalt drill
bits for stainless steel.

Dave

david lang wrote:

John Rumm wrote:


Comments as usual please.


Great as usual. Additions - drills stands? And the use of Cobalt drill
bits for stainless steel.

OK, Will add a section on drill stands to the end of the metal drilling
bit since that seems to be where it fits best.

As to cobalt, how about a new section after coated drills:

"Cobalt Drills

Another variation on the metal drilling theme. Cobalt drills are hard!
They are designed to drill very hard materials like stainless steel. The
only common DIY application that you are likely to find for these is
drilling out the remains of other broken drill bits!"

Sound OK? Anything else to add?


--
Cheers,

John.

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| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

John Rumm wrote:
As to cobalt, how about a new section after coated drills:

"Cobalt Drills

Another variation on the metal drilling theme. Cobalt drills are hard!
They are designed to drill very hard materials like stainless steel. The
only common DIY application that you are likely to find for these is
drilling out the remains of other broken drill bits!"

Will they really drill through HSS, though?

John Rumm wrote:
david lang wrote:

John Rumm wrote:


Comments as usual please.



Great as usual. Additions - drills stands? And the use of Cobalt
drill bits for stainless steel.


OK, Will add a section on drill stands to the end of the metal drilling
bit since that seems to be where it fits best.

As to cobalt, how about a new section after coated drills:

"Cobalt Drills

Another variation on the metal drilling theme. Cobalt drills are hard!
They are designed to drill very hard materials like stainless steel. The
only common DIY application that you are likely to find for these is
drilling out the remains of other broken drill bits!"

Sound OK? Anything else to add?

Yes :-)

Having been at the blunt end of drills used in the aerospace industry
for many years, cobalt drills are only one step above a standard HHS
twist drill. They can be blunted with some stainless steels though.

The next step up is called a C 1150. This has short flutes and a longer
shank than normal.

After this comes a D 200 twist drill. Looks quite a lot like a HSS twist
drill, so you have to look at the packet it comes in. Quite a good drill
to have for stainless.

As an aside, I had to drill some steel that the Italians had supplied
for a modification to an aircraft wing. It was so hard, that the 2.5 mm
pilot drill I was using would last just 3 holes before refusing to drill
any further. I spent more time walking to the grindstone than drilling
holes :-(

The Italian rep passed this job one day and observed that a fellow
worker had turned the colour of the paint on these panels a light brown
colour (it is normally yellow).

Italian 'Your drill is blunt.'

Brit. 'No! Your metal is too hard.'

Italian. 'Yees, we should take the designer round the corner and keel him.'

:-)

You are quite right about lots of pressure and a slow rotational speed
when drilling hard metals. If you let up on the pressure, you end up
polishing the metal. By the way, put the pressure on and _then_ start to
drill. When you decide to stop drilling, keep the speed up and _quickly_
remove the twist drill.

When drilling pure aluminium, there can be a build up of swarf that
sticks to the drill cutting edge. A fast rotation speed can reduce this
risk, if used with a slow feed rate.

When drilling thin sheet, no matter what you do, you will end up with a
triangular hole if you do not have something quite solid under the
metal. Whatever this is, it must be quite solid. I would imagine
something like MDF to be OK.

The use of subsequently larger drill, to avoid this, does not work if
the twist drill you are drilling with has nothing to hold it on its path
at half break through point. (This is the point when the drill decides
to make a triangular hole.)

Finally, in my experience, comes the solid tungsten carbide drill. Now
this is a beast. It will drill and cut into an easy out, or also known
as an extractor tool for a broken stud/bolt. (quite hard steel in its
own right). I would imagine that it could cut into any of the above
drills, if you could keep it on centre.

Finally, there is a diamond drill, but I have had no experience of these.

HTH

Dave

Dave wrote:

Yes :-)

Having been at the blunt end of drills used in the aerospace industry
for many years, cobalt drills are only one step above a standard HHS
twist drill. They can be blunted with some stainless steels though.

Thanks for that! (I knew that metal drilling was going to end up being a
FAQ in its own right almost).

If you have no objections I shall plagiarise that with due haste!


--
Cheers,

John.

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

John Rumm wrote:
Dave wrote:

Yes :-)

Having been at the blunt end of drills used in the aerospace industry
for many years, cobalt drills are only one step above a standard HHS
twist drill. They can be blunted with some stainless steels though.


Thanks for that! (I knew that metal drilling was going to end up being a
FAQ in its own right almost).

If you have no objections I shall plagiarise that with due haste!


Plague away :-)

Dave

"John Rumm" wrote in message


Thanks for that! (I knew that metal drilling was going to end up being a
FAQ in its own right almost).

But where are all these frequently asked questions frequently asked?

The only thread on drilling in here in the last few years has been the
FAQs.




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A mention of cone-cutters and step drills for drilling largish holes in
thin sheet metal? I use an excellent 4-12mm step drill for making
holes for switches and such like in aluminium panels.
Give a good clean round hole, especially if you make the last cut from
the other side, and very little danger of grabbing.

dcbwhaley wrote:

A mention of cone-cutters and step drills for drilling largish holes in
thin sheet metal? I use an excellent 4-12mm step drill for making
holes for switches and such like in aluminium panels.
Give a good clean round hole, especially if you make the last cut from
the other side, and very little danger of grabbing.

Yup, forgot that. Added ;-)


--
Cheers,

John.

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