Recent awning job required some special brackets, had them made by a
local engineer.

Excellent job, but due to a misunderstanding - Desmonds fault, no more
chocky biscuits for a while - the holes were 11mm not 12mm.

Bought a pack of 5 x 13mm Silverline HSS bits from Toolstation on the
way to the job. They appear to have been made of recycled cheese.

I would have thought enlarging an 11mm hole to 13mm would have been easy
- even in 3mm steel - but it wasn't.

Took Desmond about 15 mins per hole, snapped 2 bits & wore out the rest.

Is that down to crap drill bits, or is it a difficult job?



--
Dave - The Medway Handyman www.medwayhandyman.co.uk

I've read that the best way to open out a hole accurately is not with a
drill bit but with a five-sided reamer. Depending on the thickness of the
material this can leave a slightly tapered hole, but once one aperture is at
the final size, a bit can be used. I've never had occasion to try it
though.

Bert

On Wed, 29 Jun 2011 23:57:36 +0100, Bert Coules wrote:

I've read that the best way to open out a hole accurately is not with a
drill bit but with a five-sided reamer.

A reamer is good but it would be hard work in 3mm steel.

How was desmond trying to drill out the holes, hand held? What speed
was the drill running at?

Ideally one would have used a pillar drill and a slowish speed with
the bracket held in a drill vice.

--
Cheers
Dave.

On 29/06/11 23:53, The Medway Handyman wrote:
Recent awning job required some special brackets, had them made by a
local engineer.

Excellent job, but due to a misunderstanding - Desmonds fault, no more
chocky biscuits for a while - the holes were 11mm not 12mm.

Bought a pack of 5 x 13mm Silverline HSS bits from Toolstation on the
way to the job. They appear to have been made of recycled cheese.

I would have thought enlarging an 11mm hole to 13mm would have been easy
- even in 3mm steel - but it wasn't.

Took Desmond about 15 mins per hole, snapped 2 bits & wore out the rest.

Is that down to crap drill bits, or is it a difficult job?

Cone drill: http://www.screwfix.com/p/cone-drill-bit-set/45562#

On 30/06/2011 00:08, Dave Liquorice wrote:
On Wed, 29 Jun 2011 23:57:36 +0100, Bert Coules wrote:

I've read that the best way to open out a hole accurately is not with a
drill bit but with a five-sided reamer.

A reamer is good but it would be hard work in 3mm steel.

How was desmond trying to drill out the holes, hand held? What speed
was the drill running at?

Hand held, 500 to 800 rpm?

Ideally one would have used a pillar drill and a slowish speed with
the bracket held in a drill vice.

Alas we were on site so had to use what w had.


--
Dave - The Medway Handyman www.medwayhandyman.co.uk

On 30/06/2011 00:13, pcb1962 wrote:
On 29/06/11 23:53, The Medway Handyman wrote:
Recent awning job required some special brackets, had them made by a
local engineer.

Excellent job, but due to a misunderstanding - Desmonds fault, no more
chocky biscuits for a while - the holes were 11mm not 12mm.

Bought a pack of 5 x 13mm Silverline HSS bits from Toolstation on the
way to the job. They appear to have been made of recycled cheese.

I would have thought enlarging an 11mm hole to 13mm would have been easy
- even in 3mm steel - but it wasn't.

Took Desmond about 15 mins per hole, snapped 2 bits & wore out the rest.

Is that down to crap drill bits, or is it a difficult job?

Cone drill: http://www.screwfix.com/p/cone-drill-bit-set/45562#

Did think of that, but TS didn't have one in stock.

--
Dave - The Medway Handyman www.medwayhandyman.co.uk

The Medway Handyman wrote:
Recent awning job required some special brackets, had them made by a
local engineer.

Excellent job, but due to a misunderstanding - Desmonds fault, no more
chocky biscuits for a while - the holes were 11mm not 12mm.

Typical blaming someone else when you brag that you are the expert!

A poor workman *always* blames his tools and a poor employer *always* blames
his employees!

Bought a pack of 5 x 13mm Silverline HSS bits from Toolstation on the
way to the job. They appear to have been made of recycled cheese.

May not be a problem with the drill bit, but perhaps you should try varying
the speed of the drill (lower) and using a lubricant on some metals - and
even making sure that you have the right cutting angle on the tip of the bit
for the metal being cut.

Before you start your usual invective, just have a google and you will find
the answer (try the wikki pages) - or even read a decent engineering book.

I would have thought enlarging an 11mm hole to 13mm would have been
easy - even in 3mm steel - but it wasn't.

A 2mm enlargement to a pre-drilled hole - easy enough for all but the least
experienced!

Took Desmond about 15 mins per hole, snapped 2 bits & wore out the
rest.

So what about you using your "great expertise" to resolve the problem,
rather than blaming someone else?

Is that down to crap drill bits, or is it a difficult job?

What about someone doing something that he knows little about ?

Was "Desmond" using the power drill at its maximum speed thus causing the
bits to overheat (that would explain the "wearing out") and any number of
other reasons of misuse causing the snapping of the bits.


All the above presumes that these "special" brackets made out of mild steel
and not some exotic metal - as you have failed to give some fairly basic
information yet again.

And you have the temerity to call me a fool.


Bloody amateurs!

On 29/06/2011 23:53, The Medway Handyman wrote:
Recent awning job required some special brackets, had them made by a
local engineer.

Excellent job, but due to a misunderstanding - Desmonds fault, no more
chocky biscuits for a while - the holes were 11mm not 12mm.

Bought a pack of 5 x 13mm Silverline HSS bits from Toolstation on the
way to the job. They appear to have been made of recycled cheese.

I would have thought enlarging an 11mm hole to 13mm would have been easy
- even in 3mm steel - but it wasn't.

Took Desmond about 15 mins per hole, snapped 2 bits & wore out the rest.

Is that down to crap drill bits, or is it a difficult job?

Wrong job for a twist drill. They are designed to drill into a flat
surface, not to open up existing holes.

As others have said, a cone drill or tapered reamer are what you want
or, failing those, a round or half-round file and patience.

Colin Bignell

In article ,
The Medway Handyman wrote:
Recent awning job required some special brackets, had them made by a
local engineer.

Excellent job, but due to a misunderstanding - Desmonds fault, no more
chocky biscuits for a while - the holes were 11mm not 12mm.

Bought a pack of 5 x 13mm Silverline HSS bits from Toolstation on the
way to the job. They appear to have been made of recycled cheese.

I would have thought enlarging an 11mm hole to 13mm would have been easy
- even in 3mm steel - but it wasn't.

Took Desmond about 15 mins per hole, snapped 2 bits & wore out the rest.

Is that down to crap drill bits, or is it a difficult job?

You snapped a 13mm HSS drill? ;-)

It should have been an easy job, using a slow speed and reasonably high
pressure.

--
*Everyone has a photographic memory. Some just don't have film*

Dave Plowman London SW
To e-mail, change noise into sound.

In article ,
Nightjar \cpb\@ insertmysurnamehere wrote:
Wrong job for a twist drill. They are designed to drill into a flat
surface, not to open up existing holes.

Eh? I was taught to drill a pilot hole first. On pretty well any material.

--
*Never test the depth of the water with both feet.*

Dave Plowman London SW
To e-mail, change noise into sound.

On Thu, 30 Jun 2011 00:37:45 +0100, Unbeliever wrote:

Typical blaming someone else when you brag that you are the expert!

A poor workman *always* blames his tools and a poor employer *always*
blames his employees!
....
Before you start your usual invective, just have a google and you will
find the answer (try the wikki pages) - or even read a decent
engineering book.
....
A 2mm enlargement to a pre-drilled hole - easy enough for all but the
least experienced!
....
So what about you using your "great expertise" to resolve the problem,
rather than blaming someone else?
....
And you have the temerity to call me a fool.

What did TMH do to deserve that invective? He was relating his account of
a job and asking if Silverline-brand bits were crap or if it was to be
expected of this sort of job. Seemed reasonable enough to me: guy's a
handyman not a specialist machine-shop engineer.

Did he upset you in another thread? Your "great expertise" quote suggests
a reference to a post elsewhere. I might be more inclined to employ Dave
as a handyman than as a diplomat, but I don't think anything he said in
this thread merited that response.

--
John Stumbles

In message , John
Rumm writes
On 29/06/2011 23:53, The Medway Handyman wrote:
Recent awning job required some special brackets, had them made by a
local engineer.

Excellent job, but due to a misunderstanding - Desmonds fault, no more
chocky biscuits for a while - the holes were 11mm not 12mm.

Bought a pack of 5 x 13mm Silverline HSS bits from Toolstation on the
way to the job. They appear to have been made of recycled cheese.

I would have thought enlarging an 11mm hole to 13mm would have been easy
- even in 3mm steel - but it wasn't.

Took Desmond about 15 mins per hole, snapped 2 bits & wore out the rest.

Is that down to crap drill bits, or is it a difficult job?

Its certainly easier in a drill press, however assuming these were mild
steel brackets, then even if not ideally suited to the job, a HSS bit
should have done it relatively easily.

(your favoured bosch mm bits would have probably done a better job).

I have had mixed experience with Silverline items.

Opening out a hole without adequate clamping and hand held tools is
always going to be difficult. Particularly where there is so little
*uncut* material to support the cutting edge of the drill bit.

One technique I was shown as an apprentice is to *back off* the cutting
points. I have long forgotten the actual cutting angle on a properly
sharpened bit but, if this is made nearer to 90deg. by judicious use of
the ubiquitous angle grinder, the cut swarf will not *snatch* the drill
so easily.

regards




--
Tim Lamb

On Thu, 30 Jun 2011 00:58:41 +0100, Dave Plowman (News) wrote:

In article ,
The Medway Handyman wrote:
Recent awning job required some special brackets, had them made by a
local engineer.

Excellent job, but due to a misunderstanding - Desmonds fault, no more
chocky biscuits for a while - the holes were 11mm not 12mm.

Bought a pack of 5 x 13mm Silverline HSS bits from Toolstation on the
way to the job. They appear to have been made of recycled cheese.

I would have thought enlarging an 11mm hole to 13mm would have been easy
- even in 3mm steel - but it wasn't.

Took Desmond about 15 mins per hole, snapped 2 bits & wore out the rest.

Is that down to crap drill bits, or is it a difficult job?

You snapped a 13mm HSS drill? ;-)

It should have been an easy job, using a slow speed and reasonably high
pressure.

True with a drill, but this was Silverline Highly Suspect ****!
--
Peter.
The gods will stay away
whilst religions hold sway

On 30/06/2011 00:58, Dave Plowman (News) wrote:
In ,
The Medway wrote:
Recent awning job required some special brackets, had them made by a
local engineer.

Excellent job, but due to a misunderstanding - Desmonds fault, no more
chocky biscuits for a while - the holes were 11mm not 12mm.

Bought a pack of 5 x 13mm Silverline HSS bits from Toolstation on the
way to the job. They appear to have been made of recycled cheese.

I would have thought enlarging an 11mm hole to 13mm would have been easy
- even in 3mm steel - but it wasn't.

Took Desmond about 15 mins per hole, snapped 2 bits& wore out the rest.

Is that down to crap drill bits, or is it a difficult job?

You snapped a 13mm HSS drill? ;-)

Desmond did. Two in fact - which makes me suspect the bits were made
from recycled cheese.

It should have been an easy job, using a slow speed and reasonably high
pressure.


Thats what I thought :-(

--
Dave - The Medway Handyman www.medwayhandyman.co.uk

wrote:

The Medway Handyman wrote:
Recent awning job required some special brackets, had them made by a
local engineer.

Excellent job, but due to a misunderstanding - Desmonds fault, no more
chocky biscuits for a while - the holes were 11mm not 12mm.

Typical blaming someone else when you brag that you are the expert!

A poor workman *always* blames his tools and a poor employer *always*
blames his employees!

Oh **** off, you sound like a bloody broken record.
--
Tim Watts

On Thu, 30 Jun 2011 00:34:43 +0100, The Medway Handyman wrote:

How was desmond trying to drill out the holes, hand held? What
speed
was the drill running at?

Hand held, 500 to 800 rpm?

And being on site no good secure means of holding the brackets? The
speed is a little high for handheld but let the tool do the work.
Just hold it as firmly as you can into the hole and don't push hard.
Pushing hard will make the drill cut deeper and with such a small
amount of metal involved very likely to grab, twist and snap the
drill...

For on site a 10mm round file might have been a better bet than
trying to use drills or, unless it was a long way. back to the
workshop and the pillar drill and not charged for the time.

--
Cheers
Dave.

On Thu, 30 Jun 2011 01:01:00 +0100, Dave Plowman (News) wrote:

Wrong job for a twist drill. They are designed to drill into a
flat
surface, not to open up existing holes.

Eh? I was taught to drill a pilot hole first. On pretty well any
material.

Yeah but a pilot hole shouldn't be much bigger than the little line
on the main drill where the ground faces meet in the center. That
must have a name...

You had a "pilot" hole nearly as large as the wanted size, just 1mm
of metal all round to remove. A twist drill should manage it *if* you
can control it, keep it centred and don't feed to fast. That was
never going to be easy hand held.

--
Cheers
Dave.

On 30 Jun 2011 03:06:30 GMT, John Stumbles wrote:

What did TMH do to deserve that invective?

Ignore it John "Unbeliever" and TMH don't hit it off. "Unbeliever" is
a troll and TMH (normally) feeds the troll...

TBH "Unbeliever" appears perfect but *everyone* makes mistakes he
just hasn't the bottle to ever admit them or acknowledge that there
may be gaps in his perfect knowledge. Unlike TMH and many others who
are happy to ask "the stupid question" or admit to fups.

--
Cheers
Dave.

On 30/06/2011 01:01, Dave Plowman (News) wrote:
In articleIIOdnVeU7LR3JZbTnZ2dnUVZ8u2dnZ2d@giganews. com,
Nightjar\cpb\@insertmysurnamehere wrote:
Wrong job for a twist drill. They are designed to drill into a flat
surface, not to open up existing holes.

Eh? I was taught to drill a pilot hole first. On pretty well any material.

Presumably, you were also taught to select the pilot drill be holding it
up to the web of the larger drill, to check they were the same size or,
at most, marginally larger. The web has no cutting edges and the pilot
hole reduces the load when drilling with the larger drill. It is also
useful as a guide when everything is not firmly clamped or if the main
drill is not absolutely sharp and might otherwise tend to produce a
slightly triangular cut.

To open up a hole that is not far off the finished size, you need
something that uses the existing hole to guide its cut, such as a taper
reamer or a step drill with the right sizes of step. A two flute drill
does not do that. A three flute drill would be better, but are not
common. You can get away with a two-flute drill, but only if the work
piece is firmly clamped in a pillar drill and the hole and drill have
been properly aligned.

Colin Bignell

On 30/06/2011 08:50, The Medway Handyman wrote:
On 30/06/2011 00:58, Dave Plowman (News) wrote:
In ,
The Medway wrote:
Recent awning job required some special brackets, had them made by a
local engineer.

Excellent job, but due to a misunderstanding - Desmonds fault, no more
chocky biscuits for a while - the holes were 11mm not 12mm.

Bought a pack of 5 x 13mm Silverline HSS bits from Toolstation on the
way to the job. They appear to have been made of recycled cheese.

I would have thought enlarging an 11mm hole to 13mm would have been easy
- even in 3mm steel - but it wasn't.

Took Desmond about 15 mins per hole, snapped 2 bits& wore out the rest.

Is that down to crap drill bits, or is it a difficult job?

You snapped a 13mm HSS drill? ;-)

Desmond did. Two in fact - which makes me suspect the bits were made
from recycled cheese.

It should have been an easy job, using a slow speed and reasonably high
pressure.


Thats what I thought :-(


It sounds they snagged and he was using a rather large drill with lots
of inertia.

Opening up a large hole by just 2mm, and with a bit with two cutting
faces isn't as easy as it may look. The drill will purchase unevenly on
each side causing the bit to alternatively snatch either side.

A reamer or indeed any bit with multiple cutting faces would have been
easier.

In article ,
PeterC wrote:
True with a drill, but this was Silverline Highly Suspect ****!

Think it's like all these brands where the actual tools are sourced from
different makers. I recently bought a Silverline 'Helicoil' kit which I
used in steel with no problems. A genuine one from my local tool shop plus
the correct drill would have cost 4 times as much.

I also have a Silverline threaded rivet tool which works just fine - and
appears well made.

FWIW, the special size drill in the thread kit had a very well ground dual
angle tip. Which enlarged 10 holes in 15mm plate to take the threads
nicely with no signs of distress. But I was using a slow speed in a drill
press. But it wasn't an ordinary HSS drill.

--
*A journey of a thousand sites begins with a single click *

Dave Plowman London SW
To e-mail, change noise into sound.

In article ,
Nightjar \cpb\@ insertmysurnamehere wrote:
To open up a hole that is not far off the finished size, you need
something that uses the existing hole to guide its cut, such as a taper
reamer or a step drill with the right sizes of step. A two flute drill
does not do that. A three flute drill would be better, but are not
common. You can get away with a two-flute drill, but only if the work
piece is firmly clamped in a pillar drill and the hole and drill have
been properly aligned.

Which would explain the three flute drill in a 'helicoil' set I bought
recently.

However, for MHM's purposes (probably just enlarging a hole to take a
fixing not yet made) an ordinary twist drill will do the job. It's not
exactly a precision task.

--
*Why isn't there mouse-flavoured cat food?

Dave Plowman London SW
To e-mail, change noise into sound.

Unbeliever wrote:
The Medway Handyman wrote:
Recent awning job required some special brackets, had them made by a
local engineer.

Excellent job, but due to a misunderstanding - Desmonds fault, no
more chocky biscuits for a while - the holes were 11mm not 12mm.

Typical blaming someone else when you brag that you are the expert!

A poor workman *always* blames his tools and a poor employer *always*
blames his employees!

Now why could I see your post coming from a mile away?

--
Adam

On Thu, 30 Jun 2011 10:04:58 +0100, Nightjar \"cpb\"@ wrote:

To open up a hole that is not far off the finished size, you need
something that uses the existing hole to guide its cut, such as a taper
reamer or a step drill with the right sizes of step.

The ones I've used have steep tapers between one step and the next so are
pretty much ideal for this sort of job. But IIRC TMH stated earlier in
this thread that that's what he'd wanted but Toolstation didn't have them.

--
John Stumbles

A stitch in time saves nine. If it ain't broke, don't fix it.

The Medway Handyman wrote:
Cone drill: http://www.screwfix.com/p/cone-drill-bit-set/45562#

Did think of that, but TS didn't have one in stock.

a half-inch countersink would have done this job nicely.




--
Murphy's ultimate law is that if something that could go wrong doesn't,
it turns out that it would have been better if it had gone wrong.

On 30/06/2011 11:21, John Stumbles wrote:
On Thu, 30 Jun 2011 10:04:58 +0100, Nightjar\"cpb\"@ wrote:

To open up a hole that is not far off the finished size, you need
something that uses the existing hole to guide its cut, such as a taper
reamer or a step drill with the right sizes of step.

The ones I've used have steep tapers between one step and the next so are
pretty much ideal for this sort of job. But IIRC TMH stated earlier in
this thread that that's what he'd wanted but Toolstation didn't have them.


Hence my alternative suggestion of a file and patience.

Colin Bignell

On 30/06/2011 11:14, Dave Plowman (News) wrote:
In article3o2dnRupJpanoZHTnZ2dnUVZ8gGdnZ2d@giganews. com,
Nightjar\cpb\@insertmysurnamehere wrote:
To open up a hole that is not far off the finished size, you need
something that uses the existing hole to guide its cut, such as a taper
reamer or a step drill with the right sizes of step. A two flute drill
does not do that. A three flute drill would be better, but are not
common. You can get away with a two-flute drill, but only if the work
piece is firmly clamped in a pillar drill and the hole and drill have
been properly aligned.

Which would explain the three flute drill in a 'helicoil' set I bought
recently.

However, for MHM's purposes (probably just enlarging a hole to take a
fixing not yet made) an ordinary twist drill will do the job. It's not
exactly a precision task.


Bouncing about the hole, hitting only on the tips of the cutting edges
quickly knackers the drills, as he found. There is also a risk of the
drill snatching in the hole and spinning the workpiece, if it is not
firmly clamped down.

Colin Bignell

On Thu, 30 Jun 2011 11:10:17 +0100, Dave Plowman (News) wrote:

In article ,
PeterC wrote:
True with a drill, but this was Silverline Highly Suspect ****!

Think it's like all these brands where the actual tools are sourced from
different makers. I recently bought a Silverline 'Helicoil' kit which I
used in steel with no problems. A genuine one from my local tool shop plus
the correct drill would have cost 4 times as much.

I also have a Silverline threaded rivet tool which works just fine - and
appears well made.

FWIW, the special size drill in the thread kit had a very well ground dual
angle tip. Which enlarged 10 holes in 15mm plate to take the threads
nicely with no signs of distress. But I was using a slow speed in a drill
press. But it wasn't an ordinary HSS drill.

That's the problem - not knowing if it'll be good or bad.
I recently bought a small, rotary, wire brush for the drill to remove old
paint in the corners of an angle iron frame. The brush is Silverline and,
after use on 3 - 4 sq. cm., is about half gone! It was cheap to buy but
extrapolating...!
--
Peter.
The gods will stay away
whilst religions hold sway

On Thu, 30 Jun 2011 10:44:06 +0100, Fredxx wrote:

On 30/06/2011 08:50, The Medway Handyman wrote:
On 30/06/2011 00:58, Dave Plowman (News) wrote:
In ,
The Medway wrote:
Recent awning job required some special brackets, had them made by a
local engineer.

Excellent job, but due to a misunderstanding - Desmonds fault, no more
chocky biscuits for a while - the holes were 11mm not 12mm.

Bought a pack of 5 x 13mm Silverline HSS bits from Toolstation on the
way to the job. They appear to have been made of recycled cheese.

I would have thought enlarging an 11mm hole to 13mm would have been easy
- even in 3mm steel - but it wasn't.

Took Desmond about 15 mins per hole, snapped 2 bits& wore out the rest.

Is that down to crap drill bits, or is it a difficult job?

You snapped a 13mm HSS drill? ;-)

Desmond did. Two in fact - which makes me suspect the bits were made
from recycled cheese.

It should have been an easy job, using a slow speed and reasonably high
pressure.


Thats what I thought :-(


It sounds they snagged and he was using a rather large drill with lots
of inertia.

Opening up a large hole by just 2mm, and with a bit with two cutting
faces isn't as easy as it may look. The drill will purchase unevenly on
each side causing the bit to alternatively snatch either side.

A reamer or indeed any bit with multiple cutting faces would have been
easier.

Preferably an odd number, then it won't chatter (bounce) diametrically.

ISTR seeing 3-flute bits somewhere.
--
Peter.
The gods will stay away
whilst religions hold sway

On Thu, 30 Jun 2011 09:25:24 +0100 (BST), Dave Liquorice wrote:

On Thu, 30 Jun 2011 01:01:00 +0100, Dave Plowman (News) wrote:

Wrong job for a twist drill. They are designed to drill into a
flat
surface, not to open up existing holes.

Eh? I was taught to drill a pilot hole first. On pretty well any
material.

Yeah but a pilot hole shouldn't be much bigger than the little line
on the main drill where the ground faces meet in the center. That
must have a name...

You had a "pilot" hole nearly as large as the wanted size, just 1mm
of metal all round to remove. A twist drill should manage it *if* you
can control it, keep it centred and don't feed to fast. That was
never going to be easy hand held.

Bit OT: I'm about to enlarge a hole through the wall from 22mm to 25mm -
that could be interesting.
--
Peter.
The gods will stay away
whilst religions hold sway

PeterC wrote:
On Thu, 30 Jun 2011 09:25:24 +0100 (BST), Dave Liquorice wrote:

On Thu, 30 Jun 2011 01:01:00 +0100, Dave Plowman (News) wrote:

Wrong job for a twist drill. They are designed to drill into a
flat
surface, not to open up existing holes.

Eh? I was taught to drill a pilot hole first. On pretty well any
material.

Yeah but a pilot hole shouldn't be much bigger than the little line
on the main drill where the ground faces meet in the center. That
must have a name...

You had a "pilot" hole nearly as large as the wanted size, just 1mm
of metal all round to remove. A twist drill should manage it *if* you
can control it, keep it centred and don't feed to fast. That was
never going to be easy hand held.

Bit OT: I'm about to enlarge a hole through the wall from 22mm to
25mm - that could be interesting.

Even with an SDS masonry bit you may still have fun with the drill bit
snagging:-)

It will depend on the hardness of the bricks and the power of the drill.
Enjoy.

--
Adam

PeterC wrote:
On Thu, 30 Jun 2011 10:44:06 +0100, Fredxx wrote:

On 30/06/2011 08:50, The Medway Handyman wrote:
On 30/06/2011 00:58, Dave Plowman (News) wrote:
In ,
The Medway wrote:
Recent awning job required some special brackets, had them made by a
local engineer.

Excellent job, but due to a misunderstanding - Desmonds fault, no more
chocky biscuits for a while - the holes were 11mm not 12mm.

Bought a pack of 5 x 13mm Silverline HSS bits from Toolstation on the
way to the job. They appear to have been made of recycled cheese.

I would have thought enlarging an 11mm hole to 13mm would have been easy
- even in 3mm steel - but it wasn't.

Took Desmond about 15 mins per hole, snapped 2 bits& wore out the rest.

Is that down to crap drill bits, or is it a difficult job?

You snapped a 13mm HSS drill? ;-)

Desmond did. Two in fact - which makes me suspect the bits were made
from recycled cheese.

It should have been an easy job, using a slow speed and reasonably high
pressure.


Thats what I thought :-(


It sounds they snagged and he was using a rather large drill with lots
of inertia.

Opening up a large hole by just 2mm, and with a bit with two cutting
faces isn't as easy as it may look. The drill will purchase unevenly on
each side causing the bit to alternatively snatch either side.

A reamer or indeed any bit with multiple cutting faces would have been
easier.

Preferably an odd number, then it won't chatter (bounce) diametrically.

ISTR seeing 3-flute bits somewhere.
All fluted cutters bounce to some degree and usually create a polygonal
hole with one more side than the number of flutes.

Bob

On Thu, 30 Jun 2011 12:44:27 +0100, Bob Minchin wrote:

PeterC wrote:
On Thu, 30 Jun 2011 10:44:06 +0100, Fredxx wrote:

On 30/06/2011 08:50, The Medway Handyman wrote:
On 30/06/2011 00:58, Dave Plowman (News) wrote:
In ,
The Medway wrote:
Recent awning job required some special brackets, had them made by a
local engineer.

Excellent job, but due to a misunderstanding - Desmonds fault, no more
chocky biscuits for a while - the holes were 11mm not 12mm.

Bought a pack of 5 x 13mm Silverline HSS bits from Toolstation on the
way to the job. They appear to have been made of recycled cheese.

I would have thought enlarging an 11mm hole to 13mm would have been easy
- even in 3mm steel - but it wasn't.

Took Desmond about 15 mins per hole, snapped 2 bits& wore out the rest.

Is that down to crap drill bits, or is it a difficult job?

You snapped a 13mm HSS drill? ;-)

Desmond did. Two in fact - which makes me suspect the bits were made
from recycled cheese.

It should have been an easy job, using a slow speed and reasonably high
pressure.


Thats what I thought :-(


It sounds they snagged and he was using a rather large drill with lots
of inertia.

Opening up a large hole by just 2mm, and with a bit with two cutting
faces isn't as easy as it may look. The drill will purchase unevenly on
each side causing the bit to alternatively snatch either side.

A reamer or indeed any bit with multiple cutting faces would have been
easier.

Preferably an odd number, then it won't chatter (bounce) diametrically.

ISTR seeing 3-flute bits somewhere.
All fluted cutters bounce to some degree and usually create a polygonal
hole with one more side than the number of flutes.

Bob

Yes - it looks as if it's a constant diameter polygon, like 20p and 50p
coins.
--
Peter.
The gods will stay away
whilst religions hold sway

"Unbeliever" wrote in message
...
Big Snip

And you have the temerity to call me a fool.


Bloody amateurs!



You "Unbeliever" are a nasty person, please crawl back under your bridge.
And Stay There.

Baz

"Tim Lamb" wrote in message
...
Snip
Opening out a hole without adequate clamping and hand held tools is always
going to be difficult. Particularly where there is so little *uncut*
material to support the cutting edge of the drill bit.

One technique I was shown as an apprentice is to *back off* the cutting
points. I have long forgotten the actual cutting angle on a properly
sharpened bit but, if this is made nearer to 90deg. by judicious use of
the ubiquitous angle grinder, the cut swarf will not *snatch* the drill so
easily.

regards




--
Tim Lamb

Also a very good technique for drilling thin sheet.

Baz

On 30/06/2011 15:30, John Rumm wrote:
Ah well, unbeliever seems to have a bit of a thing for our Dave, and you
know where the bitterness of unrequited love can lead. How sad does your
existence have to be before stalking and trolling one individual seems
worthwhile?

Ask Dave - he spends much more time trolling urc than anything positive
here. Well, I say trolling, but there's nothing subtle or skilled about it.

On 30/06/2011 00:44, Nightjar "cpb"@ insertmysurnamehere wrote:
On 29/06/2011 23:53, The Medway Handyman wrote:
Recent awning job required some special brackets, had them made by a
local engineer.

Excellent job, but due to a misunderstanding - Desmonds fault, no more
chocky biscuits for a while - the holes were 11mm not 12mm.

Bought a pack of 5 x 13mm Silverline HSS bits from Toolstation on the
way to the job. They appear to have been made of recycled cheese.

I would have thought enlarging an 11mm hole to 13mm would have been easy
- even in 3mm steel - but it wasn't.

Took Desmond about 15 mins per hole, snapped 2 bits & wore out the rest.

Is that down to crap drill bits, or is it a difficult job?

Wrong job for a twist drill. They are designed to drill into a flat
surface, not to open up existing holes.

As others have said, a cone drill or tapered reamer are what you want
or, failing those, a round or half-round file and patience.

Having been involved with twist drills and drilling all sorts of
materials from the age of 15 to my retirement at the age of 53, I
disagree with you. The drilling of all sorts of steel is simple, but the
secret is the speed of rotation of the twist drill and the angle that
the cutting edge presents to that metal.

Dave

On 30/06/2011 10:04, Nightjar "cpb"@ insertmysurnamehere wrote:
On 30/06/2011 01:01, Dave Plowman (News) wrote:
In articleIIOdnVeU7LR3JZbTnZ2dnUVZ8u2dnZ2d@giganews. com,
Nightjar\cpb\@insertmysurnamehere wrote:
Wrong job for a twist drill. They are designed to drill into a flat
surface, not to open up existing holes.

Eh? I was taught to drill a pilot hole first. On pretty well any
material.

Presumably, you were also taught to select the pilot drill be holding it
up to the web of the larger drill, to check they were the same size or,
at most, marginally larger. The web has no cutting edges and the pilot
hole reduces the load when drilling with the larger drill. It is also
useful as a guide when everything is not firmly clamped or if the main
drill is not absolutely sharp and might otherwise tend to produce a
slightly triangular cut.

To open up a hole that is not far off the finished size, you need
something that uses the existing hole to guide its cut, such as a taper
reamer or a step drill with the right sizes of step. A two flute drill
does not do that. A three flute drill would be better, but are not
common. You can get away with a two-flute drill, but only if the work
piece is firmly clamped in a pillar drill and the hole and drill have
been properly aligned.

Knowing your background, I can understand why you are saying this, but I
can tell you that opening up a hole will not produce a triangular hole
in a piece of metal thicker than about 7/8s of the thickness
of the diam. of the drill. BTDTWTTS

Dave

In article ,
John Rumm wrote:
What would you suggest is the best solution for this particular
application (i.e. opening a 11mm hole in 3mm mild steel by a couple of
mm while on site?)

I really can't see any problem doing this with an ordinary HSS bit
provided you have a drill that runs slow enough. Unless I'm missing
something, it doesn't need to be precision engineering.

--
*Wrinkled was not one of the things I wanted to be when I grew up

Dave Plowman London SW
To e-mail, change noise into sound.

On 30/06/2011 04:06, John Stumbles wrote:


What did TMH do to deserve that invective?

Well, in this thread, and NG, nothing.

And untill 2 days ago, I took him more-or-less as he appears here. Sane,
prepared to ask when needed etc.

But...

2 days ago, my opinion changed radically. I subscribed to the cycling
NG uk.rec.cycling.

It appears that TMH is not a cyclist, but chooses to be a mega-troll on
that NG, posting as 'Dave- Cyclist VOR' ( whatever that means ).

Why the hell would someone who is not only not a cyclist, with no
interest in cycling, but a rabid anti-cyclist, go there and cause
trouble? Just go away from there. Stop trolling. Just go away.

His presence on that NG is entirely negative and trolling, and his posts
are unbelievable rants.

Dave, if DIY and handymaning is your thing, then I welcome your
contribution here.

Please give your trolling a rest on the cycling NG. You don't enjoy
trolls here, and I don't enjoy them over there either.

--
Ron