I have some (boat) windows that I'm refurbishing. They are secured to
the boat superstructure with little aluminium wedges with grub screws
through them. Absolutely ridiculaous steel (not even stainless) grub
screws in aluminium but I have to deal with what's there.

I removed one window a few weeks ago by angle-grinding through some of
the grub screws and simply knocking out other wedges with a hammer.
For that window I drilled out all of the grub screws, cleaned up the
holes with a tap and put new stainless steel grub screws in (still not
ideal but I can see no obvious alternative).

So, I'm starting on the next window and wondering if there's a better
approach than drilling and re-tapping all the holes. I can knock the
wedges out OK and I'm wondering if there's some obvious sort of
chemical bath that I can soak the wedge plus grub screw in so that I
might be able to get the grub screws out. They're quite small, maybe
1" long by 1/2" square section (they're not actually square) so don't
need a big 'bath'. I can get a vice onto the projecting end of the
grub screw so I can apply a fair amount of force but I need some help
before they'll move I think. The grub screws are M8.

Any bright ideas anyone? Or should I simply give up and drill them
all?

--
Chris Green
·

In message <1tblck-m0o91.ln1@esprimo.zbmc.eu>, Chris Green <cl@isbd.net>
writes
>I have some (boat) windows that I'm refurbishing. They are secured to
>the boat superstructure with little aluminium wedges with grub screws
>through them. Absolutely ridiculaous steel (not even stainless) grub
>screws in aluminium but I have to deal with what's there.
>
>I removed one window a few weeks ago by angle-grinding through some of
>the grub screws and simply knocking out other wedges with a hammer.
>For that window I drilled out all of the grub screws, cleaned up the
>holes with a tap and put new stainless steel grub screws in (still not
>ideal but I can see no obvious alternative).
>
>So, I'm starting on the next window and wondering if there's a better
>approach than drilling and re-tapping all the holes. I can knock the
>wedges out OK and I'm wondering if there's some obvious sort of
>chemical bath that I can soak the wedge plus grub screw in so that I
>might be able to get the grub screws out. They're quite small, maybe
>1" long by 1/2" square section (they're not actually square) so don't
>need a big 'bath'. I can get a vice onto the projecting end of the
>grub screw so I can apply a fair amount of force but I need some help
>before they'll move I think. The grub screws are M8.
>
>Any bright ideas anyone? Or should I simply give up and drill them
>all?
Can you apply local heat to the screws? Not easy when fitted but bit of
red hot bar might cause enough local expansion for WD40 etc. to
penetrate when cool.
>

--
Tim Lamb

On 18/03/2024 10:16, Tim Lamb wrote:
> In message <1tblck-m0o91.ln1@esprimo.zbmc.eu>, Chris Green <cl@isbd.net>
> writes
>> I have some (boat) windows that I'm refurbishing.  They are secured to
>> the boat superstructure with little aluminium wedges with grub screws
>> through them.  Absolutely ridiculaous steel (not even stainless) grub
>> screws in aluminium but I have to deal with what's there.

<snip>

>> Any bright ideas anyone?  Or should I simply give up and drill them
>> all?

> Can you apply local heat to the screws? Not easy when fitted but bit of
> red hot bar might cause enough local expansion for WD40 etc. to
> penetrate when cool.

I've no idea if this would work, but desperate times...

Connect a car battery, one lead to the aluminium frame and the other
lead to your screwdriver/allen key - probably limit the current via a
headlight bulb in series at least to start (well, you wanted a bright
idea). Wear goggles and keep a swear box handy.

--
Cheers
Clive

On 18/03/2024 08:51, Chris Green wrote:
> I have some (boat) windows that I'm refurbishing. They are secured to
> the boat superstructure with little aluminium wedges with grub screws
> through them. Absolutely ridiculaous steel (not even stainless) grub
> screws in aluminium but I have to deal with what's there.
>
> I removed one window a few weeks ago by angle-grinding through some of
> the grub screws and simply knocking out other wedges with a hammer.
> For that window I drilled out all of the grub screws, cleaned up the
> holes with a tap and put new stainless steel grub screws in (still not
> ideal but I can see no obvious alternative).
>
> So, I'm starting on the next window and wondering if there's a better
> approach than drilling and re-tapping all the holes. I can knock the
> wedges out OK and I'm wondering if there's some obvious sort of
> chemical bath that I can soak the wedge plus grub screw in so that I
> might be able to get the grub screws out. They're quite small, maybe
> 1" long by 1/2" square section (they're not actually square) so don't
> need a big 'bath'. I can get a vice onto the projecting end of the
> grub screw so I can apply a fair amount of force but I need some help
> before they'll move I think. The grub screws are M8.
>
> Any bright ideas anyone? Or should I simply give up and drill them
> all?

I'm trying to picture "aluminium wedges with grub screws through them"
and how that would hold windows.

I would expect the aluminium to corrode and swell to keep the grub-screw
captive. I'm not sure if stainless would fare much better.

If you are successful in removing the grub scree in soft aluminium then
I might continue with doing that. I don't think anything will dissolve
the grub screw that won't make a mess of the aluminium.

If the wedges are out of sight then Aluminium oxide is dissolved with
most alkalis and acids. People have mentioned citric acid but not
something I have ever used.

Tim's idea of heat might work relying on the different expansion of
steel and aluminium. Best use penetrating oil after or you'll add carbon
to the mix of oxides.

On 18 Mar 2024 at 08:51:13 GMT, Chris Green wrote:

> I have some (boat) windows that I'm refurbishing. They are secured to
> the boat superstructure with little aluminium wedges with grub screws
> through them. Absolutely ridiculaous steel (not even stainless) grub
> screws in aluminium but I have to deal with what's there.
>
> I removed one window a few weeks ago by angle-grinding through some of
> the grub screws and simply knocking out other wedges with a hammer.
> For that window I drilled out all of the grub screws, cleaned up the
> holes with a tap and put new stainless steel grub screws in (still not
> ideal but I can see no obvious alternative).
>
> So, I'm starting on the next window and wondering if there's a better
> approach than drilling and re-tapping all the holes. I can knock the
> wedges out OK and I'm wondering if there's some obvious sort of
> chemical bath that I can soak the wedge plus grub screw in so that I
> might be able to get the grub screws out. They're quite small, maybe
> 1" long by 1/2" square section (they're not actually square) so don't
> need a big 'bath'. I can get a vice onto the projecting end of the
> grub screw so I can apply a fair amount of force but I need some help
> before they'll move I think. The grub screws are M8.
>
> Any bright ideas anyone? Or should I simply give up and drill them
> all?

FWIW, I faced something similar and drilling was the only way for most of the
screws - so a couple of good quality cobalt bits of varying size.

A couple I multitooled flats to the head of the screw and that gave just
enough purchase to shift them with a hammer/sacrificial chisel.
--
Cheers, Rob, Sheffield UK

On 18/03/2024 08:51, Chris Green wrote:
> I have some (boat) windows that I'm refurbishing. They are secured to
> the boat superstructure with little aluminium wedges with grub screws
> through them. Absolutely ridiculaous steel (not even stainless) grub
> screws in aluminium but I have to deal with what's there.
>
> I removed one window a few weeks ago by angle-grinding through some of
> the grub screws and simply knocking out other wedges with a hammer.
> For that window I drilled out all of the grub screws, cleaned up the
> holes with a tap and put new stainless steel grub screws in (still not
> ideal but I can see no obvious alternative).
>
> So, I'm starting on the next window and wondering if there's a better
> approach than drilling and re-tapping all the holes. I can knock the
> wedges out OK and I'm wondering if there's some obvious sort of
> chemical bath that I can soak the wedge plus grub screw in so that I
> might be able to get the grub screws out. They're quite small, maybe
> 1" long by 1/2" square section (they're not actually square) so don't
> need a big 'bath'. I can get a vice onto the projecting end of the
> grub screw so I can apply a fair amount of force but I need some help
> before they'll move I think. The grub screws are M8.
>
> Any bright ideas anyone? Or should I simply give up and drill them
> all?
>

Find a reverse action hand drill and maybe some lefhand drill bits ,
rare as hens teeth, and their housing has to be marked LEFT HAND in very
big letters.
Failing that some ordinary drill bits and grind a reverse rake angle at
the tips. Often just the reverse action itself will shift them without
having to drill into the grubs

--
Global sea level rise to 2100 from curve-fitted existing altimetry data
<http://diverse.4mg.com/slr.htm>

On 18/03/2024 11:40, Clive Arthur wrote:
> On 18/03/2024 10:16, Tim Lamb wrote:
>> In message <1tblck-m0o91.ln1@esprimo.zbmc.eu>, Chris Green
>> <cl@isbd.net> writes
>>> I have some (boat) windows that I'm refurbishing.  They are secured to
>>> the boat superstructure with little aluminium wedges with grub screws
>>> through them.  Absolutely ridiculaous steel (not even stainless) grub
>>> screws in aluminium but I have to deal with what's there.

> Connect a car battery, one lead to the aluminium frame and the other
> lead to your screwdriver/allen key - probably limit the current via a
> headlight bulb in series at least to start (well, you wanted a bright
> idea).  Wear goggles and keep a swear box handy.
>
There are simpler ways
https://www.machinemart.co.uk/p/clarke-it1500-1500w-induction-heating-kit/
Sadly these are not things that are falling off the shelves for £20 in
LIDL...

In your case reverse drills and a reverse thread stud extractor, or
drill the whole lot out and re tap is probably best cost-benefit approach.

https://www.amazon.co.uk/left-handed-drill-bits/s?k=left+handed+drill+bits

https://www.amazon.co.uk/CYH-T-Handle-Ratchet-Adjustable-Threading/dp/B09CG65SBZ/

Mild steel screws in aluminium threads are a disaster waiting to happen
in a marine environment.

If these wedges can come out and onto the bench, then it will be easier
to totally refurbish the whole shebang properly.

Or you can make new ones. I am not clear (picture would help) onm
exactly how this all hangs together

--
Civilization exists by geological consent, subject to change without notice.
– Will Durant

On 18/03/2024 12:14, N_Cook wrote:
> Find a reverse action hand drill and maybe some lefhand drill bits ,
> rare as hens teeth, and their housing has to be marked LEFT HAND in very
> big letters.

Common as muck on Amazon Ebay etc. He is not the first person with this
exact problem

The hardest part is drilling centrally - clamping on a pillar drill is
top way.

--
“Progress is precisely that which rules and regulations did not foresee,”

– Ludwig von Mises

On 18/03/2024 08:51, Chris Green wrote:

>
> Any bright ideas anyone? Or should I simply give up and drill them
> all?
>

Impact driver?

Alternatively

First gently tap it in using a hammer at the end of the tool you use to
undo the screw

--
mailto : news {at} admac {dot} myzen {dot} co {dot} uk

On 18/03/2024 11:45, Fredxx wrote:

> I would expect the aluminium to corrode and swell to keep the grub-screw
> captive. I'm not sure if stainless would fare much better.

If it's not required to torque down the grub screws perhaps a good
coating with grease (or an anti-seize compound) in the threads would
prevent further seizure.

--
mailto : news {at} admac {dot} myzen {dot} co {dot} uk

On 18/03/2024 15:03, alan_m wrote:
> On 18/03/2024 11:45, Fredxx wrote:
>
>> I would expect the aluminium to corrode and swell to keep the
>> grub-screw captive. I'm not sure if stainless would fare much better.
>
> If it's not required to torque down the grub screws perhaps a good
> coating with grease (or an anti-seize compound) in the threads would
> prevent further seizure.
>
Even torqued down something that seals the gap against moisture but
without gluing it all together would be excellent. That is what anti
seize is, of course...
--
“People believe certain stories because everyone important tells them,
and people tell those stories because everyone important believes them.
Indeed, when a conventional wisdom is at its fullest strength, one’s
agreement with that conventional wisdom becomes almost a litmus test of
one’s suitability to be taken seriously.”

Paul Krugman

Tim Lamb <tim@marfordfarm.demon.co.uk> wrote:
> In message <1tblck-m0o91.ln1@esprimo.zbmc.eu>, Chris Green <cl@isbd.net>
> writes
> >I have some (boat) windows that I'm refurbishing. They are secured to
> >the boat superstructure with little aluminium wedges with grub screws
> >through them. Absolutely ridiculaous steel (not even stainless) grub
> >screws in aluminium but I have to deal with what's there.
> >
> >I removed one window a few weeks ago by angle-grinding through some of
> >the grub screws and simply knocking out other wedges with a hammer.
> >For that window I drilled out all of the grub screws, cleaned up the
> >holes with a tap and put new stainless steel grub screws in (still not
> >ideal but I can see no obvious alternative).
> >
> >So, I'm starting on the next window and wondering if there's a better
> >approach than drilling and re-tapping all the holes. I can knock the
> >wedges out OK and I'm wondering if there's some obvious sort of
> >chemical bath that I can soak the wedge plus grub screw in so that I
> >might be able to get the grub screws out. They're quite small, maybe
> >1" long by 1/2" square section (they're not actually square) so don't
> >need a big 'bath'. I can get a vice onto the projecting end of the
> >grub screw so I can apply a fair amount of force but I need some help
> >before they'll move I think. The grub screws are M8.
> >
> >Any bright ideas anyone? Or should I simply give up and drill them
> >all?
> Can you apply local heat to the screws? Not easy when fitted but bit of
> red hot bar might cause enough local expansion for WD40 etc. to
> penetrate when cool.

It would be easy enough to heat the lump of aluminium (with the grub
screw in it) as I have removed them from the window/boat. I guess
that might help a bit.

--
Chris Green
·

N_Cook <diverse@tcp.co.uk> wrote:
> On 18/03/2024 08:51, Chris Green wrote:
> > I have some (boat) windows that I'm refurbishing. They are secured to
> > the boat superstructure with little aluminium wedges with grub screws
> > through them. Absolutely ridiculaous steel (not even stainless) grub
> > screws in aluminium but I have to deal with what's there.
> >
> > I removed one window a few weeks ago by angle-grinding through some of
> > the grub screws and simply knocking out other wedges with a hammer.
> > For that window I drilled out all of the grub screws, cleaned up the
> > holes with a tap and put new stainless steel grub screws in (still not
> > ideal but I can see no obvious alternative).
> >
> > So, I'm starting on the next window and wondering if there's a better
> > approach than drilling and re-tapping all the holes. I can knock the
> > wedges out OK and I'm wondering if there's some obvious sort of
> > chemical bath that I can soak the wedge plus grub screw in so that I
> > might be able to get the grub screws out. They're quite small, maybe
> > 1" long by 1/2" square section (they're not actually square) so don't
> > need a big 'bath'. I can get a vice onto the projecting end of the
> > grub screw so I can apply a fair amount of force but I need some help
> > before they'll move I think. The grub screws are M8.
> >
> > Any bright ideas anyone? Or should I simply give up and drill them
> > all?
> >
>
> Find a reverse action hand drill and maybe some lefhand drill bits ,
> rare as hens teeth, and their housing has to be marked LEFT HAND in very
> big letters.
> Failing that some ordinary drill bits and grind a reverse rake angle at
> the tips. Often just the reverse action itself will shift them without
> having to drill into the grubs
>
None of the first lot I drilled out came out even when I had drilled a
6.5mm hole down the middle of the M8 grub screw. In many cases I had
to use a punch to knock out the remains.

--
Chris Green
·

The Natural Philosopher <tnp@invalid.invalid> wrote:
> On 18/03/2024 15:03, alan_m wrote:
> > On 18/03/2024 11:45, Fredxx wrote:
> >
> >> I would expect the aluminium to corrode and swell to keep the
> >> grub-screw captive. I'm not sure if stainless would fare much better.
> >
> > If it's not required to torque down the grub screws perhaps a good
> > coating with grease (or an anti-seize compound) in the threads would
> > prevent further seizure.
> >
> Even torqued down something that seals the gap against moisture but
> without gluing it all together would be excellent. That is what anti
> seize is, of course...
>
So what anti-seize should one use on steel/aluminium threads?

--
Chris Green
·

The Natural Philosopher <tnp@invalid.invalid> wrote:
> On 18/03/2024 11:40, Clive Arthur wrote:
> > On 18/03/2024 10:16, Tim Lamb wrote:
> >> In message <1tblck-m0o91.ln1@esprimo.zbmc.eu>, Chris Green
> >> <cl@isbd.net> writes
> >>> I have some (boat) windows that I'm refurbishing.  They are secured to
> >>> the boat superstructure with little aluminium wedges with grub screws
> >>> through them.  Absolutely ridiculaous steel (not even stainless) grub
> >>> screws in aluminium but I have to deal with what's there.
>
> > Connect a car battery, one lead to the aluminium frame and the other
> > lead to your screwdriver/allen key - probably limit the current via a
> > headlight bulb in series at least to start (well, you wanted a bright
> > idea).  Wear goggles and keep a swear box handy.
> >
> There are simpler ways
> https://www.machinemart.co.uk/p/clarke-it1500-1500w-induction-heating-kit/
> Sadly these are not things that are falling off the shelves for £20 in
> LIDL...
>
> In your case reverse drills and a reverse thread stud extractor, or
> drill the whole lot out and re tap is probably best cost-benefit approach.
>
This is essentially what I did with the first few, I was just looking
for a better/easier way! :-)

> https://www.amazon.co.uk/left-handed-drill-bits/s?k=left+handed+drill+bits
>
> https://www.amazon.co.uk/CYH-T-Handle-Ratchet-Adjustable-Threading/dp/B09CG65SBZ/
>
> Mild steel screws in aluminium threads are a disaster waiting to happen
> in a marine environment.
>
Absolutely! I fail to understand why a 'professional' business making
windows for boats would do such a thing, but there you are. They've
been in business since at least 1976 (when my boat was built)!

> If these wedges can come out and onto the bench, then it will be easier
> to totally refurbish the whole shebang properly.
>
As I said, using brute force (a hammer) I can get them out without
serious damage to anything, just a few minor deformations of the
aluminium.

> Or you can make new ones. I am not clear (picture would help) onm
> exactly how this all hangs together
>
Here's a picture, end on, of a clean, new one:-

https://gvps.uk/pics/wedge.jpg

....and this is a rather poor picture of them in my boat:-

https://gvps.uk/pics/p1040188.jpg

I think you can probably make out how they work.

--
Chris Green
·

The Natural Philosopher <tnp@invalid.invalid> wrote:
> On 18/03/2024 12:14, N_Cook wrote:
> > Find a reverse action hand drill and maybe some lefhand drill bits ,
> > rare as hens teeth, and their housing has to be marked LEFT HAND in very
> > big letters.
>
> Common as muck on Amazon Ebay etc. He is not the first person with this
> exact problem
>
> The hardest part is drilling centrally - clamping on a pillar drill is
> top way.
>
Fortunately I can get them off the window so I can take them home and
I do have a pillar drill. It's quite laborious though and there's
probably a hundred or more to deal with.

--
Chris Green
·

Fredxx <fredxx@spam.invalid> wrote:
> On 18/03/2024 08:51, Chris Green wrote:
> > I have some (boat) windows that I'm refurbishing. They are secured to
> > the boat superstructure with little aluminium wedges with grub screws
> > through them. Absolutely ridiculaous steel (not even stainless) grub
> > screws in aluminium but I have to deal with what's there.
> >
> > I removed one window a few weeks ago by angle-grinding through some of
> > the grub screws and simply knocking out other wedges with a hammer.
> > For that window I drilled out all of the grub screws, cleaned up the
> > holes with a tap and put new stainless steel grub screws in (still not
> > ideal but I can see no obvious alternative).
> >
> > So, I'm starting on the next window and wondering if there's a better
> > approach than drilling and re-tapping all the holes. I can knock the
> > wedges out OK and I'm wondering if there's some obvious sort of
> > chemical bath that I can soak the wedge plus grub screw in so that I
> > might be able to get the grub screws out. They're quite small, maybe
> > 1" long by 1/2" square section (they're not actually square) so don't
> > need a big 'bath'. I can get a vice onto the projecting end of the
> > grub screw so I can apply a fair amount of force but I need some help
> > before they'll move I think. The grub screws are M8.
> >
> > Any bright ideas anyone? Or should I simply give up and drill them
> > all?
>
> I'm trying to picture "aluminium wedges with grub screws through them"
> and how that would hold windows.
>
It is rather an odd set-up, but amazingly I found the company that
makes them is still in business.

As regards seeing how they work see the pictures I've posted:-

https://gvps.uk/pics/wedge.jpg
https://gvps.uk/pics/p1040188.jpg

> I would expect the aluminium to corrode and swell to keep the grub-screw
> captive. I'm not sure if stainless would fare much better.
>
I think in reality with steel and aluminium together it's the steel
that corrodes.

--
Chris Green
·

alan_m <junk@admac.myzen.co.uk> wrote:
> On 18/03/2024 11:45, Fredxx wrote:
>
> > I would expect the aluminium to corrode and swell to keep the grub-screw
> > captive. I'm not sure if stainless would fare much better.
>
> If it's not required to torque down the grub screws perhaps a good
> coating with grease (or an anti-seize compound) in the threads would
> prevent further seizure.
>
They have to be fairly tight to hold the window in tight enough to
squish the seals to waterproofness.

--
Chris Green
·

On 18/03/2024 08:51, Chris Green wrote:
> I have some (boat) windows that I'm refurbishing. They are secured to
> the boat superstructure with little aluminium wedges with grub screws
> through them. Absolutely ridiculaous steel (not even stainless) grub
> screws in aluminium but I have to deal with what's there.
>
> I removed one window a few weeks ago by angle-grinding through some of
> the grub screws and simply knocking out other wedges with a hammer.
> For that window I drilled out all of the grub screws, cleaned up the
> holes with a tap and put new stainless steel grub screws in (still not
> ideal but I can see no obvious alternative).

Would nylon do the job? If not you can get alumina ceramic set screws,
but they are a bit more expensive.

>
> So, I'm starting on the next window and wondering if there's a better
> approach than drilling and re-tapping all the holes. I can knock the
> wedges out OK and I'm wondering if there's some obvious sort of
> chemical bath that I can soak the wedge plus grub screw in so that I
> might be able to get the grub screws out. They're quite small, maybe
> 1" long by 1/2" square section (they're not actually square) so don't
> need a big 'bath'. I can get a vice onto the projecting end of the
> grub screw so I can apply a fair amount of force but I need some help
> before they'll move I think. The grub screws are M8.
>
> Any bright ideas anyone? Or should I simply give up and drill them
> all?
>

--
Colin Bignell

In message <l88mck-hdhb1.ln1@esprimo.zbmc.eu>, Chris Green <cl@isbd.net>
writes
>Fredxx <fredxx@spam.invalid> wrote:
>> On 18/03/2024 08:51, Chris Green wrote:
>> > I have some (boat) windows that I'm refurbishing. They are secured to
>> > the boat superstructure with little aluminium wedges with grub screws
>> > through them. Absolutely ridiculaous steel (not even stainless) grub
>> > screws in aluminium but I have to deal with what's there.
>> >
>> > I removed one window a few weeks ago by angle-grinding through some of
>> > the grub screws and simply knocking out other wedges with a hammer.
>> > For that window I drilled out all of the grub screws, cleaned up the
>> > holes with a tap and put new stainless steel grub screws in (still not
>> > ideal but I can see no obvious alternative).
>> >
>> > So, I'm starting on the next window and wondering if there's a better
>> > approach than drilling and re-tapping all the holes. I can knock the
>> > wedges out OK and I'm wondering if there's some obvious sort of
>> > chemical bath that I can soak the wedge plus grub screw in so that I
>> > might be able to get the grub screws out. They're quite small, maybe
>> > 1" long by 1/2" square section (they're not actually square) so don't
>> > need a big 'bath'. I can get a vice onto the projecting end of the
>> > grub screw so I can apply a fair amount of force but I need some help
>> > before they'll move I think. The grub screws are M8.
>> >
>> > Any bright ideas anyone? Or should I simply give up and drill them
>> > all?
>>
>> I'm trying to picture "aluminium wedges with grub screws through them"
>> and how that would hold windows.
>>
>It is rather an odd set-up, but amazingly I found the company that
>makes them is still in business.
>
>As regards seeing how they work see the pictures I've posted:-
>
> https://gvps.uk/pics/wedge.jpg
> https://gvps.uk/pics/p1040188.jpg
>
>
>> I would expect the aluminium to corrode and swell to keep the grub-screw
>> captive. I'm not sure if stainless would fare much better.
>>
>I think in reality with steel and aluminium together it's the steel
>that corrodes.
Have you tried a hammer type impact driver? My 60 year old set still get
some use:-)
>

--
Tim Lamb

Colin Bignell <cpb@bignellremovethis.me.uk> wrote:
> On 18/03/2024 08:51, Chris Green wrote:
> > I have some (boat) windows that I'm refurbishing. They are secured to
> > the boat superstructure with little aluminium wedges with grub screws
> > through them. Absolutely ridiculaous steel (not even stainless) grub
> > screws in aluminium but I have to deal with what's there.
> >
> > I removed one window a few weeks ago by angle-grinding through some of
> > the grub screws and simply knocking out other wedges with a hammer.
> > For that window I drilled out all of the grub screws, cleaned up the
> > holes with a tap and put new stainless steel grub screws in (still not
> > ideal but I can see no obvious alternative).
>
> Would nylon do the job? If not you can get alumina ceramic set screws,
> but they are a bit more expensive.
>
Yes, I wondered about nylon, it would certainly address the corrosion
problem. The only question would be if they can 'pull' hard enough.

--
Chris Green
·

On 18/03/2024 19:05, Tim Lamb wrote:
> In message <l88mck-hdhb1.ln1@esprimo.zbmc.eu>, Chris Green <cl@isbd.net>
> writes
>> Fredxx <fredxx@spam.invalid> wrote:
>>> On 18/03/2024 08:51, Chris Green wrote:
>>> > I have some (boat) windows that I'm refurbishing.  They are secured to
>>> > the boat superstructure with little aluminium wedges with grub screws
>>> > through them.  Absolutely ridiculaous steel (not even stainless) grub
>>> > screws in aluminium but I have to deal with what's there.
>>> >
>>> > I removed one window a few weeks ago by angle-grinding through some of
>>> > the grub screws and simply knocking out other wedges with a hammer.
>>> > For that window I drilled out all of the grub screws, cleaned up the
>>> > holes with a tap and put new stainless steel grub screws in (still not
>>> > ideal but I can see no obvious alternative).
>>> >
>>> > So, I'm starting on the next window and wondering if there's a better
>>> > approach than drilling and re-tapping all the holes.  I can knock the
>>> > wedges out OK and I'm wondering if there's some obvious sort of
>>> > chemical bath that I can soak the wedge plus grub screw in so that I
>>> > might be able to get the grub screws out.  They're quite small, maybe
>>> > 1" long by 1/2" square section (they're not actually square) so don't
>>> > need a big 'bath'.  I can get a vice onto the projecting end of the
>>> > grub screw so I can apply a fair amount of force but I need some help
>>> > before they'll move I think. The grub screws are M8.
>>> >
>>> > Any bright ideas anyone?  Or should I simply give up and drill them
>>> > all?
>>>
>>> I'm trying to picture "aluminium wedges with grub screws through them"
>>> and how that would hold windows.
>>>
>> It is rather an odd set-up, but amazingly I found the company that
>> makes them is still in business.
>>
>> As regards seeing how they work see the pictures I've posted:-
>>
>>  https://gvps.uk/pics/wedge.jpg
>>  https://gvps.uk/pics/p1040188.jpg
>>
>>
>>> I would expect the aluminium to corrode and swell to keep the grub-screw
>>> captive. I'm not sure if stainless would fare much better.
>>>
>> I think in reality with steel and aluminium together it's the steel
>> that corrodes.
> Have you tried a hammer type impact driver? My 60 year old set still get
> some use:-)
>>
>
Ah, why didn't you say 'clamps' instead of 'wedges'

If they are still made, why not get new ones and grind the old ones off?

PS in a marine environment, its a race whether aluminium degrades faster
than steel.

--
"In our post-modern world, climate science is not powerful because it is
true: it is true because it is powerful."

Lucas Bergkamp

On Mon, 18 Mar 2024 13:21:11 +0000
The Natural Philosopher <tnp@invalid.invalid> wrote:

>
> Mild steel screws in aluminium threads are a disaster waiting to
> happen in a marine environment.
>
>

Marine? Have you tried removing alloy wheels from steel hubs after a
few years in fairly mild inland weather? Yes, I dropped the car (gently
and with precautions) onto the wheel after removing the bolts. Not a
sign of movement.

I followed the advice of the Internet, and used progressively larger
chunks of timber to bash the wheel on alternate sides, and eventually
it came loose.

Not a trace of salt...

--
Joe

The Natural Philosopher <tnp@invalid.invalid> wrote:
[snip]
> >
> Ah, why didn't you say 'clamps' instead of 'wedges'
>
Because they're a cross between the two! :-)

> If they are still made, why not get new ones and grind the old ones off?
>
I was very surprised to find that the *were* still made. They're over
£2 each so if I can re-use some it will save me some money. There's
well over a hundred of them on eight windows.

> PS in a marine environment, its a race whether aluminium degrades faster
> than steel.
>
This is inland waterway rather than sea, but it's still wet. :-)

--
Chris Green
·

On Mon, 18 Mar 2024 16:57:31 +0000, Chris Green <cl@isbd.net> wrote:

>So what anti-seize should one use on steel/aluminium threads?

I'm finding stuff called "marine-grade anti-seize"... one has zinc in it and
says "for threaded steel parts assembled in aluminum or zinc castings" (LOCTITE®
LB 8044, zinc dust plus petrolatum.)

I'd add a wrap of PTFE tape, and maybe use hex grub screws?

Thomas Prufer