Removing a broken self tapper
 

I've got a couple of very small self tappers which have broken off flush
with a blind housing made of thin mild steel - car bodywork. Due to being
rusted in place. What's the best way to remove them with minimum damage to
the bodywork?

--
*Acupuncture is a jab well done*

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

Removing a broken self tapper
 

On Thu, 26 Nov 2009 09:53:51 +0000 (GMT), "Dave Plowman (News)"
wrote:

I've got a couple of very small self tappers which have broken off flush
with a blind housing made of thin mild steel - car bodywork. Due to being
rusted in place. What's the best way to remove them with minimum damage to
the bodywork?

Angle grinder.

--
Frank Erskine

Removing a broken self tapper
 

On Thu, 26 Nov 2009 09:53:51 +0000 (GMT), Dave Plowman (News) wrote:

I've got a couple of very small self tappers which have broken off flush
with a blind housing made of thin mild steel - car bodywork. Due to
being rusted in place. What's the best way to remove them with minimum
damage to the bodywork?

Carefully. ouch

Squirt with PlusGas and leave for a day, or a spot of diesel if you
have no PlusGas. Then I'd try the one of the JML Screw Removers that
Homebase are (were?) selling for £4.99/set. But being self tappers
they might be too hard for the remover to cut into to get a grip.

--
Cheers
Dave.

Removing a broken self tapper
 

In article ,
Frank Erskine wrote:
I've got a couple of very small self tappers which have broken off
flush with a blind housing made of thin mild steel - car bodywork. Due
to being rusted in place. What's the best way to remove them with
minimum damage to the bodywork?

Angle grinder.

You could at least have modified it for small and made it a Dremel?

--
*A woman drove me to drink and I didn't have the decency to thank her

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

Removing a broken self tapper
 

Frank Erskine
wibbled on Thursday 26 November 2009 10:46

On Thu, 26 Nov 2009 09:53:51 +0000 (GMT), "Dave Plowman (News)"
wrote:

I've got a couple of very small self tappers which have broken off flush
with a blind housing made of thin mild steel - car bodywork. Due to being
rusted in place. What's the best way to remove them with minimum damage to
the bodywork?

Angle grinder.


I raise you "thermite"

:)

--
Tim Watts

This space intentionally left blank...

Removing a broken self tapper
 

Dave Plowman (News) wrote:

I've got a couple of very small self tappers which have broken off flush
with a blind housing made of thin mild steel - car bodywork. Due to being
rusted in place. What's the best way to remove them with minimum damage to
the bodywork?



How small?

Axminster do 3mm tungsten burrs which I used when I broke a drill inside a
stud I was trying to drill out.

AJH

Removing a broken self tapper
 

On Nov 26, 9:53*am, "Dave Plowman (News)"
wrote:
I've got a couple of very small self tappers which have broken off flush
with a blind housing made of thin mild steel - car bodywork. Due to being
rusted in place. What's the best way to remove them with minimum damage to
the bodywork?


Cobalt drill bit


NT

Removing a broken self tapper
 

Dave Plowman (News) wrote:
I've got a couple of very small self tappers which have broken off flush
with a blind housing made of thin mild steel - car bodywork. Due to being
rusted in place. What's the best way to remove them with minimum damage to
the bodywork?

Proper self tappers will be too hard to drill out.
Grinding is a possibility with a high speed (air) die grinder.
If you can support nearby from behind with something like a heavy lump
of metal eg club hammer head, you might be able to punch it through.
One or more small holes drilled close by in the panel might aid the
punching process.

Not nice or easy which ever way you choose.

Bob

Removing a broken self tapper
 

On 26 Nov, 09:53, "Dave Plowman (News)" wrote:
I've got a couple of very small self tappers which have broken off flush
with a blind housing made of thin mild steel - car bodywork.

Angle grinder, make them flat & flush, leave the wreckage in place.

Ideally move the new fastener location sideways to dodge the mess.

Removing a broken self tapper
 

Dave Plowman (News) wrote:
I've got a couple of very small self tappers which have broken off flush
with a blind housing made of thin mild steel - car bodywork. Due to being
rusted in place. What's the best way to remove them with minimum damage to
the bodywork?

To do this, you will need two things.
An extreamly hard drill and some means of stopping the twist drill from
going off the centre of the self tapper and through the softer metal
around it.

The twist drill could have to be a solid tungsten carbide one (or
possibly a C 1150 or D 200, but I have hit a brick wall in finding a
source of them. They are considerably harder than a cobalt drill.) and
the only way you can prevent it taking the easy way through the softer
body metal is to use a hardened bush that can be clamped onto the body
metal, to guide it through the screw. Unless you are very adept at
making the drill stay on course.

An alternative, but maybe expensive way, would be to find someone who
can electrically erode it, by spark erosion.

Good luck. If it was a local job, I would get out my hard drills and do
it for you.

Dave

Removing a broken self tapper
 

In article ,
Dave wrote:
Dave Plowman (News) wrote:
I've got a couple of very small self tappers which have broken off flush
with a blind housing made of thin mild steel - car bodywork. Due to being
rusted in place. What's the best way to remove them with minimum damage to
the bodywork?

To do this, you will need two things.
An extreamly hard drill and some means of stopping the twist drill from
going off the centre of the self tapper and through the softer metal
around it.

The twist drill could have to be a solid tungsten carbide one (or
possibly a C 1150 or D 200, but I have hit a brick wall in finding a
source of them. They are considerably harder than a cobalt drill.) and
the only way you can prevent it taking the easy way through the softer
body metal is to use a hardened bush that can be clamped onto the body
metal, to guide it through the screw. Unless you are very adept at
making the drill stay on course.

I do have tungsten carbide drills I use for drilling PCBs. But not sure
I'd risk them on this - even if I could rig things up to use the PCB drill
press.

An alternative, but maybe expensive way, would be to find someone who
can electrically erode it, by spark erosion.

Good luck. If it was a local job, I would get out my hard drills and do
it for you.

Thanks for the offer. ;-)

Dave

--
*Strip mining prevents forest fires.

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

Removing a broken self tapper
 

Dave Plowman (News) wrote:
I've got a couple of very small self tappers which have broken off
flush with a blind housing made of thin mild steel - car bodywork.
Due to being rusted in place. What's the best way to remove them
with minimum damage to the bodywork?

Why do you need to remove them at all? Are there no other fixing points?

Removing a broken self tapper
 

In article ,
GB wrote:
I've got a couple of very small self tappers which have broken off
flush with a blind housing made of thin mild steel - car bodywork.
Due to being rusted in place. What's the best way to remove them
with minimum damage to the bodywork?

Why do you need to remove them at all? Are there no other fixing points?

The 'if there are four screws two will do' syndrome? ;-)

Suppose they could be repositioned - but not until I'm certain they can't
be removed.

--
*Snowmen fall from Heaven unassembled*

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

Removing a broken self tapper
 

Dave Plowman (News) wrote:
In article ,
GB wrote:
I've got a couple of very small self tappers which have broken off
flush with a blind housing made of thin mild steel - car bodywork.
Due to being rusted in place. What's the best way to remove them
with minimum damage to the bodywork?

Why do you need to remove them at all? Are there no other fixing points?

The 'if there are four screws two will do' syndrome? ;-)

Suppose they could be repositioned - but not until I'm certain they can't
be removed.

drill and use stud extractor maybe.

Personally I'd _angle grind_ (TM) flat and drill 'next door'
Or use CARBODYFILLER (TM)

Do I get extra points?

Removing a broken self tapper
 

On Fri, 27 Nov 2009 16:39:29 +0000, Dave Plowman (News) wrote:
Suppose they could be repositioned - but not until I'm certain they can't
be removed.

You might be able to drill them and replace... failing that:

1) Completely drill the entire area and weld in new metal with appropriate
hole (pain in the backside, but perhaps appropriate if restoring something
"properly")

2) Move the fixing points as mentioned (cheap and cheerful, hopefully
do-able in such a way that someone in the future could still do point one
above if they wanted)

cheers

Jules

Removing a broken self tapper
 

In article ,
The Natural Philosopher wrote:
Suppose they could be repositioned - but not until I'm certain they
can't be removed.

drill and use stud extractor maybe.

Have you ever tried drilling a self tapper?

--
*(on a baby-size shirt) "Party -- my crib -- two a.m

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

Removing a broken self tapper
 

In article . com,
Jules wrote:
2) Move the fixing points as mentioned (cheap and cheerful, hopefully
do-able in such a way that someone in the future could still do point one
above if they wanted)

Snag is they are the fixing for a rubber seal - clamped between the body
and a steel section. It's already a rust trap so I'd rather not have any
extra holes.

--
*Half the people in the world are below average.

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

Removing a broken self tapper
 

Dave Plowman (News) wrote:
In article ,
The Natural Philosopher wrote:
Suppose they could be repositioned - but not until I'm certain they
can't be removed.

drill and use stud extractor maybe.

Have you ever tried drilling a self tapper?

large ones yes. Small ones, no.

Removing a broken self tapper
 

Dave Plowman (News) wrote:
In article ,
The Natural Philosopher wrote:
Suppose they could be repositioned - but not until I'm certain they
can't be removed.

drill and use stud extractor maybe.

Have you ever tried drilling a self tapper?

Going back to your comments about having tungsten carbide drills for
PCB's, could you get a pilot hole in the screws and open it up with the
right sized cobalt bit, freshly ground, of course?

My thinking is, that if you have one of those 12 V and tiny hand drills,
it would be ideal to control where the twist drill can wander. Just
angle the drill slightly, at 90 degrees to the direction of error, until
the tip is pointing down the centre of the screw and bring it upright again.

That didn't look right. If the twist drill is wandering to the left, you
angle it to the left, until the drill cuts back to the middle of the screw.

Dave

Removing a broken self tapper
 

In message , "Dave Plowman (News)"
writes
In article . com,
Jules wrote:
2) Move the fixing points as mentioned (cheap and cheerful, hopefully
do-able in such a way that someone in the future could still do point one
above if they wanted)

Snag is they are the fixing for a rubber seal - clamped between the body
and a steel section. It's already a rust trap so I'd rather not have any
extra holes.


Can't you just chip away at the rust until it falls out of its own
accord ?


--
geoff

Removing a broken self tapper
 

In article ,
Dave wrote:
Have you ever tried drilling a self tapper?

Going back to your comments about having tungsten carbide drills for
PCB's, could you get a pilot hole in the screws and open it up with the
right sized cobalt bit, freshly ground, of course?

I've probably got the right size tungsten carbide. Bought a load off a
workshop that closed down - including the ancient but very good PCB drill
press.

My thinking is, that if you have one of those 12 V and tiny hand drills,
it would be ideal to control where the twist drill can wander. Just
angle the drill slightly, at 90 degrees to the direction of error, until
the tip is pointing down the centre of the screw and bring it upright
again.

I'd say there's a very real chance of breaking a small tungsten carbide
used hand held.

That didn't look right. If the twist drill is wandering to the left, you
angle it to the left, until the drill cuts back to the middle of the
screw.

I could cut a cross with a Dremel to provide the centre?

--
*Virtual reality is its own reward *

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

Removing a broken self tapper
 

In article ,
geoff wrote:
In message , "Dave Plowman (News)"
writes
In article . com,
Jules wrote:
2) Move the fixing points as mentioned (cheap and cheerful, hopefully
do-able in such a way that someone in the future could still do point
one above if they wanted)

Snag is they are the fixing for a rubber seal - clamped between the body
and a steel section. It's already a rust trap so I'd rather not have any
extra holes.


Can't you just chip away at the rust until it falls out of its own
accord ?

Luckily the bit the screws go into is in pretty good nick. And I want to
keep it that way.

--
*There are 3 kinds of people: those who can count & those who can't.

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

Removing a broken self tapper
 

On Sat, 28 Nov 2009 22:58:00 +0000 (GMT), Dave Plowman (News) wrote:

I could cut a cross with a Dremel to provide the centre?

If you can do that why not just cut a slot and use a parallel sided
(not wedge shaped) straight screwdriver after the soak with
PlusGas/Diesel? Gentle use of a powered impact driver might be better
than a hand held tool. How much pressure can you apply to stop any
driver turning out without distorting the bit you want to keep?

--
Cheers
Dave.

Removing a broken self tapper
 

In article o.uk,
Dave Liquorice wrote:
I could cut a cross with a Dremel to provide the centre?

If you can do that why not just cut a slot and use a parallel sided
(not wedge shaped) straight screwdriver after the soak with
PlusGas/Diesel? Gentle use of a powered impact driver might be better
than a hand held tool. How much pressure can you apply to stop any
driver turning out without distorting the bit you want to keep?

That's how I broke them off flush in the first place. ;-)

--
*If you try to fail and succeed, which have you done? *

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

Removing a broken self tapper
 

Dave Plowman (News) wrote:
In article ,
Dave wrote:
Have you ever tried drilling a self tapper?

Going back to your comments about having tungsten carbide drills for
PCB's, could you get a pilot hole in the screws and open it up with the
right sized cobalt bit, freshly ground, of course?

I've probably got the right size tungsten carbide. Bought a load off a
workshop that closed down - including the ancient but very good PCB drill
press.

My thinking is, that if you have one of those 12 V and tiny hand drills,
it would be ideal to control where the twist drill can wander. Just
angle the drill slightly, at 90 degrees to the direction of error, until
the tip is pointing down the centre of the screw and bring it upright
again.

I'd say there's a very real chance of breaking a small tungsten carbide
used hand held.

Only if it is used in a pistol grip power drill. I also make PCB's but I
use HSS steel drill bits in a 12 Volt mini drill. (I have no problem
with regrinding them at this diam.). It has a body of about 35mm diam,
that contains the DC motor, with a very small chuck at the end. It is
very difficult to put any side force on it, unlike a pistol grip drill.
Just let the bit do the cutting without using too much force to make the
bit cut. The only problem you might encounter, is if you you do break
the bit and part of it stays in the screw, you might be stuffed at
getting the broken part out.

That didn't look right. If the twist drill is wandering to the left, you
angle it to the left, until the drill cuts back to the middle of the
screw.

I could cut a cross with a Dremel to provide the centre?

That could shatter the bit, due to the cutting edge ramping up and down
over the cut cross. I wouldn't tackle it that way.

As an aside, many years ago, I had a series of Austin Minis and they
were notorious for the brake adjusters to seize up. One was so bad I
used an easy out to try and get it to move. Needless to say, the easy
out snapped. The tungsten carbide drill I had, drilled it as if it was
butter. After that, it was out with the blow torch and use heat to
release it. That never failed. :-)

Some years ago, I bought some tungsten rotary files, one was a ball
cutter, only about 3mm in diam. Something like that would be far better
to give you a centre.

Thinking about that, why not find what used to be a Fred Aldous shop and
see if they are still available? Our local one was closed down some
years ago and it was the only place I had ever seen them. They used to
be based in Manchester.

Good luck

Dave

Removing a broken self tapper
 

On Sun, 29 Nov 2009 16:14:06 +0000 (GMT), Dave Plowman (News) wrote:

If you can do that why not just cut a slot and use a parallel
sided
(not wedge shaped) straight screwdriver after the soak with
PlusGas/Diesel? Gentle use of a powered impact driver might be
better
than a hand held tool. How much pressure can you apply to stop any
driver turning out without distorting the bit you want to keep?

That's how I broke them off flush in the first place. ;-)

Ah.

How thick is the surrounding sheet? Could you punch the remnant
through?

--
Cheers
Dave.

Removing a broken self tapper
 

In article ,
Dave wrote:
I'd say there's a very real chance of breaking a small tungsten carbide
used hand held.

Only if it is used in a pistol grip power drill. I also make PCB's but I
use HSS steel drill bits in a 12 Volt mini drill. (I have no problem
with regrinding them at this diam.). It has a body of about 35mm diam,
that contains the DC motor, with a very small chuck at the end.

Well yes. I have a similar one. And if drilling the odd PCB hole with that
I too use HSS drills. Because the tungsten carbide ones break too easily.
So I only use them in the drill press.

--
*A snooze button is a poor substitute for no alarm clock at all *

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

Removing a broken self tapper
 

In article o.uk,
Dave Liquorice wrote:
On Sun, 29 Nov 2009 16:14:06 +0000 (GMT), Dave Plowman (News) wrote:

If you can do that why not just cut a slot and use a parallel
sided
(not wedge shaped) straight screwdriver after the soak with
PlusGas/Diesel? Gentle use of a powered impact driver might be
better
than a hand held tool. How much pressure can you apply to stop any
driver turning out without distorting the bit you want to keep?

That's how I broke them off flush in the first place. ;-)

Ah.

How thick is the surrounding sheet? Could you punch the remnant
through?

I'm wary about using force in case I damage the panel. Think I'll have a
go with a small pointed grindstone to give a centre for a tungsten carbide
drill.

--
*A backward poet writes inverse.*

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

Removing a broken self tapper
 

"Dave Plowman (News)" wrote in message
...
I've got a couple of very small self tappers which have broken off flush
with a blind housing made of thin mild steel - car bodywork. Due to being
rusted in place. What's the best way to remove them with minimum damage to
the bodywork?

I had a similar experience with the door handle screws on a Golf. In the end
there was a combination of plus gas, time, cutting slots with a dremel and a
drill. I think the slots and plus gas eventually did it. I find using a
torque limited cheap electric screwdriver useful for these sorts of things -
set them to a low torque setting and high speed and you get a very light
impact driver effect that tends to get things moving. Drilling was something
of a waste of time - the screw must have been made of something tough as it
blunted drills like crazy. The heat may have helped a little though -
couldn't use a blowtorch due to the still attached plastic handle.

Removing a broken self tapper
 

Doki wrote:

"Dave Plowman (News)" wrote in message
...
I've got a couple of very small self tappers which have broken off flush
with a blind housing made of thin mild steel - car bodywork. Due to being
rusted in place. What's the best way to remove them with minimum
damage to
the bodywork?

I had a similar experience with the door handle screws on a Golf. In the
end there was a combination of plus gas, time, cutting slots with a
dremel and a drill. I think the slots and plus gas eventually did it. I
find using a torque limited cheap electric screwdriver useful for these
sorts of things - set them to a low torque setting and high speed and
you get a very light impact driver effect that tends to get things
moving. Drilling was something of a waste of time - the screw must have
been made of something tough as it blunted drills like crazy. The heat
may have helped a little though - couldn't use a blowtorch due to the
still attached plastic handle.

The problem of drilling something hard is down to the very tip of the
drill, the chisel point. If this is not hard enough to create a hole
then all effort is wasted. Once you get a hole in the metal, known as a
pilot hole, you might find that standard HSS drills will be OK to open
it up. Obviously the twist drill must be freshly sharpened and run at a
slow speed.

Dave