Removing aluminum screws from Carbon frames

Carbon and aluminum are at opposite sides of the electrolytic charts. That means that you should use aluminum screws in carbon frames since they can corrode and lock in place. I can hardly believe that is what they did on this 2018 Trek.

As it turns out, although it appears that they have a brake wire tube through the top tube, they do not. The frame has a straight line shot from one frame brake line fitting to the other. So you have to unscrew the back fitting which is on the top of the top tube, remove the small cover and fish the brake wire inserted at the front end out with a J-bend spoke or some such. And then re-assemble everything. A good mechanic knowing that the brake inner would have to be replaced sooner or later would grease the screw with a heavy, non-reactive grease so that would prevent water or sweat from attacking the metal and seizing the screw. He would also not tighten that screw beyond just closing. Surprise - the mechanic who assembled it wasn't a good mechanic and that particular cover screw is seized.

Because the screw is so small (2 mm?) none of the normal mechanical means of freeing that screw are available.

Does anyone have any workable ideas of how to loosen that screw which is almost rounded out now simply because small aluminum Allen head screws don't have any strength?

I hesitate to use anti-seize lubricants not knowing their reactions on a carbon fiber frame. It isn't as if they say the pH on the label.

On Monday, February 24, 2020 at 9:37:09 PM UTC+1, Tom Kunich wrote:
Carbon and aluminum are at opposite sides of the electrolytic charts. That means that you should use aluminum screws in carbon frames since they can corrode and lock in place. I can hardly believe that is what they did on this 2018 Trek.

As it turns out, although it appears that they have a brake wire tube through the top tube, they do not. The frame has a straight line shot from one frame brake line fitting to the other. So you have to unscrew the back fitting which is on the top of the top tube, remove the small cover and fish the brake wire inserted at the front end out with a J-bend spoke or some such. And then re-assemble everything. A good mechanic knowing that the brake inner would have to be replaced sooner or later would grease the screw with a heavy, non-reactive grease so that would prevent water or sweat from attacking the metal and seizing the screw. He would also not tighten that screw beyond just closing. Surprise - the mechanic who assembled it wasn't a good mechanic and that particular cover screw is seized.

Because the screw is so small (2 mm?) none of the normal mechanical means of freeing that screw are available.

Does anyone have any workable ideas of how to loosen that screw which is almost rounded out now simply because small aluminum Allen head screws don't have any strength?

I hesitate to use anti-seize lubricants not knowing their reactions on a carbon fiber frame. It isn't as if they say the pH on the label.

What I have succesfully used is a big enough phillips or pozidrive screwdriver and CAREFULLY (no powertool) try to unscrew the rounded allen screw. F*ck small allen screws; torx screws are the way to go.


Lou

On Mon, 24 Feb 2020 13:42:14 -0800 (PST), wrote:

On Monday, February 24, 2020 at 9:37:09 PM UTC+1, Tom Kunich wrote:
Carbon and aluminum are at opposite sides of the electrolytic charts. That means that you should use aluminum screws in carbon frames since they can corrode and lock in place. I can hardly believe that is what they did on this 2018 Trek.

As it turns out, although it appears that they have a brake wire tube through the top tube, they do not. The frame has a straight line shot from one frame brake line fitting to the other. So you have to unscrew the back fitting which is on the top of the top tube, remove the small cover and fish the brake wire inserted at the front end out with a J-bend spoke or some such. And then re-assemble everything. A good mechanic knowing that the brake inner would have to be replaced sooner or later would grease the screw with a heavy, non-reactive grease so that would prevent water or sweat from attacking the metal and seizing the screw. He would also not tighten that screw beyond just closing. Surprise - the mechanic who assembled it wasn't a good mechanic and that particular cover screw is seized.

Because the screw is so small (2 mm?) none of the normal mechanical means of freeing that screw are available.

Does anyone have any workable ideas of how to loosen that screw which is almost rounded out now simply because small aluminum Allen head screws don't have any strength?

I hesitate to use anti-seize lubricants not knowing their reactions on a carbon fiber frame. It isn't as if they say the pH on the label.

What I have succesfully used is a big enough phillips or pozidrive screwdriver and CAREFULLY (no powertool) try to unscrew the rounded allen screw. F*ck small allen screws; torx screws are the way to go.


Lou

Galvanic corrosion of Aluminum is common in marine life and
innumerable solutions have been developed. Try googling on something
like "amazon+corrosion preventative compound":
--
cheers,

John B.

On Monday, February 24, 2020 at 1:42:16 PM UTC-8, wrote:
On Monday, February 24, 2020 at 9:37:09 PM UTC+1, Tom Kunich wrote:
Carbon and aluminum are at opposite sides of the electrolytic charts. That means that you should use aluminum screws in carbon frames since they can corrode and lock in place. I can hardly believe that is what they did on this 2018 Trek.

As it turns out, although it appears that they have a brake wire tube through the top tube, they do not. The frame has a straight line shot from one frame brake line fitting to the other. So you have to unscrew the back fitting which is on the top of the top tube, remove the small cover and fish the brake wire inserted at the front end out with a J-bend spoke or some such. And then re-assemble everything. A good mechanic knowing that the brake inner would have to be replaced sooner or later would grease the screw with a heavy, non-reactive grease so that would prevent water or sweat from attacking the metal and seizing the screw. He would also not tighten that screw beyond just closing. Surprise - the mechanic who assembled it wasn't a good mechanic and that particular cover screw is seized.

Because the screw is so small (2 mm?) none of the normal mechanical means of freeing that screw are available.

Does anyone have any workable ideas of how to loosen that screw which is almost rounded out now simply because small aluminum Allen head screws don't have any strength?

I hesitate to use anti-seize lubricants not knowing their reactions on a carbon fiber frame. It isn't as if they say the pH on the label.

What I have succesfully used is a big enough phillips or pozidrive screwdriver and CAREFULLY (no powertool) try to unscrew the rounded allen screw. F*ck small allen screws; torx screws are the way to go.


Lou

That's a good idea though I would like to discover some sort of anti-corrosion solvent before trying it.

I an in complete agreement about Torx for small light parts. I'd like to see someone that isn't all thumbs round that one off.

On Mon, 24 Feb 2020 12:37:07 -0800 (PST), Tom Kunich
wrote:

Does anyone have any workable ideas of how to loosen that screw which
is almost rounded out now simply because small aluminum Allen head
screws don't have any strength?

I don't think you need any solvent or lube to remove the screw, just a
better way to grip the rounded allen head.

1. Find a small reverse spiral screw extractor and pound it into the
hole:
https://omegatec.com/1-screw-extractor.aspx
Try to keep it aligned perpendicular to the bicycle frame while
removing. If possible, clamp the bicycle frame onto a drill press
stand, and use the drill press chuck to hold the screw extractor. Do
not pound on whatever wrench you use.

2. Make your own screw extractor. Start with a drill rod and grind
it into a shape that will match the mangled hole in the screw head.
Use a Dremel tool and/or bench grinder to shape the bit. If this bit
can't get a good grip on the screw head, coat the head with some
abrasive grinding compound (found at any automotive machine shop). As
in #1, don't wiggle the bit and don't beat on the wrench.

3. If you still cannot get a decent grip on the head, clean off the
grease with 91% alcohol and use the strongest 24 hr epoxy you can find
and glue the bit into the head. Superglue (cyanoacrylate) isn't
strong enough. Maybe JB Weld. Instead of a home made bit, you might
try using a small spline or Torx wrench. These have "teeth" that will
give a better grip on the sides of the screw head, and provide some
place for the epoxy to flow. As in #1, don't wiggle and don't pound
on the wrench.

4. If you absolutely cannot make any of the aforementioned work, use
a Dremel tool and a cutoff wheel to cut a slot in the head of the
screw that will fit an ordinary screwdriver blade. Cut it to fit
tightly and not wiggle. As in #1, don't wiggle the screwdriver and
don't pound on the wrench. The problem here is that cutting the slot
will weaken the head to the point that it might crack in half, or
break where the threads start. Try not to cut too deep or make
anything that can become a stress riser (i.e. gouge).

As John B mentioned, go find a suitable aluminum anti-seize compound.
I don't have a specific recommendation, but I suggest you avoid
anything with graphite or carbon as a lubricant.

Good luck.


--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On Mon, 24 Feb 2020 18:44:02 -0800, Jeff Liebermann
wrote:

On Mon, 24 Feb 2020 12:37:07 -0800 (PST), Tom Kunich
wrote:

Does anyone have any workable ideas of how to loosen that screw which
is almost rounded out now simply because small aluminum Allen head
screws don't have any strength?

I don't think you need any solvent or lube to remove the screw, just a
better way to grip the rounded allen head.

1. Find a small reverse spiral screw extractor and pound it into the
hole:
https://omegatec.com/1-screw-extractor.aspx
Try to keep it aligned perpendicular to the bicycle frame while
removing. If possible, clamp the bicycle frame onto a drill press
stand, and use the drill press chuck to hold the screw extractor. Do
not pound on whatever wrench you use.

2. Make your own screw extractor. Start with a drill rod and grind
it into a shape that will match the mangled hole in the screw head.
Use a Dremel tool and/or bench grinder to shape the bit. If this bit
can't get a good grip on the screw head, coat the head with some
abrasive grinding compound (found at any automotive machine shop). As
in #1, don't wiggle the bit and don't beat on the wrench.

3. If you still cannot get a decent grip on the head, clean off the
grease with 91% alcohol and use the strongest 24 hr epoxy you can find
and glue the bit into the head. Superglue (cyanoacrylate) isn't
strong enough. Maybe JB Weld. Instead of a home made bit, you might
try using a small spline or Torx wrench. These have "teeth" that will
give a better grip on the sides of the screw head, and provide some
place for the epoxy to flow. As in #1, don't wiggle and don't pound
on the wrench.

4. If you absolutely cannot make any of the aforementioned work, use
a Dremel tool and a cutoff wheel to cut a slot in the head of the
screw that will fit an ordinary screwdriver blade. Cut it to fit
tightly and not wiggle. As in #1, don't wiggle the screwdriver and
don't pound on the wrench. The problem here is that cutting the slot
will weaken the head to the point that it might crack in half, or
break where the threads start. Try not to cut too deep or make
anything that can become a stress riser (i.e. gouge).

As John B mentioned, go find a suitable aluminum anti-seize compound.
I don't have a specific recommendation, but I suggest you avoid
anything with graphite or carbon as a lubricant.

Good luck.

I an a bit afraid of the term "anti-seize", in this case, as so many
anti-seizes contain some sort of metallic particles to aid in high
temperature uses. Not very useful in preventing galvanic corrosion.
One of the most useful "stuff" I used on the boat was basically
lanolin with some sort of thickener.

The last ditch solution is to (carefully) drill the stuck fitting out
and re tap the hole but I hesitate to recommend that as it does
require a certain amount of skill, the proper tools, and so on.
--
cheers,

John B.

On Tue, 25 Feb 2020 10:41:06 +0700, John B.
wrote:

I an a bit afraid of the term "anti-seize", in this case, as so many
anti-seizes contain some sort of metallic particles to aid in high
temperature uses. Not very useful in preventing galvanic corrosion.
One of the most useful "stuff" I used on the boat was basically
lanolin with some sort of thickener.

The purpose of an anti-seize compound is to:
1. Electrically insulate dissimilar metallic components from each
other.
2. Squeeze itself into the tiny surface cracks and crevasses to act
as a reservoir in case the fastener looses anti-seize (or thread lock)
compound.
3. Reflow slightly when hot or under pressure.
4. In the absence of oxygen, polymerize with metals to form a
"sticky" bond. For anti-seize, this bond is rather weak. For thread
lock, rather strong.
"Basics on Anaerobic Adhesives and Threadlockers"
https://www.reliableplant.com/Read/24136/anaerobic-adhesives-threadlockers
You can use greases to insulate and block electrolysis, but will be
missing the benefits of #4. Some greases are also not so good with
#3, where heating and solvent attack will soon cause the anti-seize to
wash away and disappear.

Incidentally, the need for cracks and crevasses for lubricants and
sealants to function is why bearing and glued surfaces are not
polished to excessive smoothness.

The last ditch solution is to (carefully) drill the stuck fitting out
and re tap the hole but I hesitate to recommend that as it does
require a certain amount of skill, the proper tools, and so on.

Nope. Try that with a threaded insert (rivet nut), and the insert
will spin out of the CF frame before the screw is drilled out.
Everything will be fine, until the drill starts to break through the
bottom end of the insert. The drill will then jam, and the power of
the drill and inertia of the chuck and armature will rip the insert
from the CF frame. If the drill has a torque limiter, it might work,
but wouldn't want to take the chance. The nice thing about doing such
things by hand is one gets some feedback just before things go
horribly wrong. Experience is all about recognizing this feedback.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On Mon, 24 Feb 2020 22:21:45 -0800, Jeff Liebermann
wrote:

On Tue, 25 Feb 2020 10:41:06 +0700, John B.
wrote:

I an a bit afraid of the term "anti-seize", in this case, as so many
anti-seizes contain some sort of metallic particles to aid in high
temperature uses. Not very useful in preventing galvanic corrosion.
One of the most useful "stuff" I used on the boat was basically
lanolin with some sort of thickener.

The purpose of an anti-seize compound is to:
1. Electrically insulate dissimilar metallic components from each
other.
Read:
https://www.autozone.com/miscellaneo...8oz/178722_0_0
https://www.antiseize.com/cop-graf-c...sed-anti-seize
https://www.antiseize.com/nickel-gra...seize-compound
https://www.permatex.com/products/lu...e-lubricant-2/

2. Squeeze itself into the tiny surface cracks and crevasses to act
as a reservoir in case the fastener looses anti-seize (or thread lock)
compound.
3. Reflow slightly when hot or under pressure.
4. In the absence of oxygen, polymerize with metals to form a
"sticky" bond. For anti-seize, this bond is rather weak. For thread
lock, rather strong.

Read the above... anti-seize isn't a thread locker.

"Basics on Anaerobic Adhesives and Threadlockers"
https://www.reliableplant.com/Read/24136/anaerobic-adhesives-threadlockers
You can use greases to insulate and block electrolysis, but will be
missing the benefits of #4. Some greases are also not so good with
#3, where heating and solvent attack will soon cause the anti-seize to
wash away and disappear.

You are talking about a totally different produce than anti-seize

Incidentally, the need for cracks and crevasses for lubricants and
sealants to function is why bearing and glued surfaces are not
polished to excessive smoothness.

The last ditch solution is to (carefully) drill the stuck fitting out
and re tap the hole but I hesitate to recommend that as it does
require a certain amount of skill, the proper tools, and so on.

Nope. Try that with a threaded insert (rivet nut), and the insert
will spin out of the CF frame before the screw is drilled out.
Everything will be fine, until the drill starts to break through the
bottom end of the insert. The drill will then jam, and the power of
the drill and inertia of the chuck and armature will rip the insert
from the CF frame. If the drill has a torque limiter, it might work,
but wouldn't want to take the chance. The nice thing about doing such
things by hand is one gets some feedback just before things go
horribly wrong. Experience is all about recognizing this feedback.

I might agree with you except that I spent quite a number of years as
a USAF Machinist drilling threaded fittings out of various objects,
amongst other things. I did mention "a certain amount of skill and
proper tools".

Believe it or not, if one has the experience, one can actually feel
when the drill bit begins to cut through the bottom of the insert -
the width of the cut is decreasing and therefore the torque
requirement is reduced - and one reduces pressure on the drill and
thus the drill cuts all the way and doesn't jam. You can even feel
the reduced cutting force required when using a drill press.
--
cheers,

John B.

On 2/25/2020 12:21 AM, Jeff Liebermann wrote:
On Tue, 25 Feb 2020 10:41:06 +0700, John B.
wrote:

I an a bit afraid of the term "anti-seize", in this case, as so many
anti-seizes contain some sort of metallic particles to aid in high
temperature uses. Not very useful in preventing galvanic corrosion.
One of the most useful "stuff" I used on the boat was basically
lanolin with some sort of thickener.

The purpose of an anti-seize compound is to:
1. Electrically insulate dissimilar metallic components from each
other.
2. Squeeze itself into the tiny surface cracks and crevasses to act
as a reservoir in case the fastener looses anti-seize (or thread lock)
compound.
3. Reflow slightly when hot or under pressure.
4. In the absence of oxygen, polymerize with metals to form a
"sticky" bond. For anti-seize, this bond is rather weak. For thread
lock, rather strong.
"Basics on Anaerobic Adhesives and Threadlockers"
https://www.reliableplant.com/Read/24136/anaerobic-adhesives-threadlockers
You can use greases to insulate and block electrolysis, but will be
missing the benefits of #4. Some greases are also not so good with
#3, where heating and solvent attack will soon cause the anti-seize to
wash away and disappear.

Incidentally, the need for cracks and crevasses for lubricants and
sealants to function is why bearing and glued surfaces are not
polished to excessive smoothness.

The last ditch solution is to (carefully) drill the stuck fitting out
and re tap the hole but I hesitate to recommend that as it does
require a certain amount of skill, the proper tools, and so on.

Nope. Try that with a threaded insert (rivet nut), and the insert
will spin out of the CF frame before the screw is drilled out.
Everything will be fine, until the drill starts to break through the
bottom end of the insert. The drill will then jam, and the power of
the drill and inertia of the chuck and armature will rip the insert
from the CF frame. If the drill has a torque limiter, it might work,
but wouldn't want to take the chance. The nice thing about doing such
things by hand is one gets some feedback just before things go
horribly wrong. Experience is all about recognizing this feedback.


+1 on your drill comments. At much higher speeds with less
feed, using a 2 or 3mm end mill and cutting fluid, grabbing
is not a problem.

--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971

On Monday, February 24, 2020 at 6:43:59 PM UTC-8, Jeff Liebermann wrote:
On Mon, 24 Feb 2020 12:37:07 -0800 (PST), Tom Kunich
wrote:

Does anyone have any workable ideas of how to loosen that screw which
is almost rounded out now simply because small aluminum Allen head
screws don't have any strength?

I don't think you need any solvent or lube to remove the screw, just a
better way to grip the rounded allen head.

1. Find a small reverse spiral screw extractor and pound it into the
hole:
https://omegatec.com/1-screw-extractor.aspx
Try to keep it aligned perpendicular to the bicycle frame while
removing. If possible, clamp the bicycle frame onto a drill press
stand, and use the drill press chuck to hold the screw extractor. Do
not pound on whatever wrench you use.

2. Make your own screw extractor. Start with a drill rod and grind
it into a shape that will match the mangled hole in the screw head.
Use a Dremel tool and/or bench grinder to shape the bit. If this bit
can't get a good grip on the screw head, coat the head with some
abrasive grinding compound (found at any automotive machine shop). As
in #1, don't wiggle the bit and don't beat on the wrench.

3. If you still cannot get a decent grip on the head, clean off the
grease with 91% alcohol and use the strongest 24 hr epoxy you can find
and glue the bit into the head. Superglue (cyanoacrylate) isn't
strong enough. Maybe JB Weld. Instead of a home made bit, you might
try using a small spline or Torx wrench. These have "teeth" that will
give a better grip on the sides of the screw head, and provide some
place for the epoxy to flow. As in #1, don't wiggle and don't pound
on the wrench.

4. If you absolutely cannot make any of the aforementioned work, use
a Dremel tool and a cutoff wheel to cut a slot in the head of the
screw that will fit an ordinary screwdriver blade. Cut it to fit
tightly and not wiggle. As in #1, don't wiggle the screwdriver and
don't pound on the wrench. The problem here is that cutting the slot
will weaken the head to the point that it might crack in half, or
break where the threads start. Try not to cut too deep or make
anything that can become a stress riser (i.e. gouge).

As John B mentioned, go find a suitable aluminum anti-seize compound.
I don't have a specific recommendation, but I suggest you avoid
anything with graphite or carbon as a lubricant.

Good luck.


--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

Those are called EZ-outs. I didn't have a reverse rotating low RPM drill to use one so I just took it up to the bike shop. That was probably a good idea as well since he described their method which is putting many layers of tape around the area because they can jump off the object. I wouldn't have done that had I the proper drill. I have a drill that switches between high and low speed but not reversing.