Hi,
After six succesful ones, I did  it again... What is the way to remove a 
M2x4 unslitted grub screw from a locked up brass ring? No EDM yet.
Tia,
Dirk

A solution in water of potassium alumium sulphate, commonly known as alum, 
will dissolve the steel without affecting the brass.

Cliff Coggin.

"PG1D/PA-11Ø12"  wrote in message 
news:793e$48aa8cdc$4df9b262$14640@news.chello.nl...
> Hi,
> After six succesful ones, I did  it again... What is the way to remove a 
> M2x4 unslitted grub screw from a locked up brass ring? No EDM yet.
> Tia,
> Dirk
>
>

"Cliff Coggin"  wrote in message 
news:RFyqk.21064$QP4.18381@newsfe19.ams2...
>A solution in water of potassium alumium sulphate, commonly known as alum, 
>will dissolve the steel without affecting the brass.
>
> Cliff Coggin.
>
> "PG1D/PA-11Ø12"  wrote in message 
> news:793e$48aa8cdc$4df9b262$14640@news.chello.nl...
>> Hi,
>> After six succesful ones, I did  it again... What is the way to remove a 
>> M2x4 unslitted grub screw from a locked up brass ring? No EDM yet.
>> Tia,
>> Dirk
>>
>>
>
>
How long will it take Cliff?   I tried the equivalent of sulphuric acid to 
get a piece of 3mm drill out of Aluminium and gave up after a long weekends 
worth of messing about.

"Steve"  wrote in message 
news:26OdnS1xieRlaDfVnZ2dnUVZ8szinZ2d@bt.com...
>
> "Cliff Coggin"  wrote in message 
> news:RFyqk.21064$QP4.18381@newsfe19.ams2...
>>A solution in water of potassium alumium sulphate, commonly known as alum, 
>>will dissolve the steel without affecting the brass.
>>
>> Cliff Coggin.
>>
>> "PG1D/PA-11Ø12"  wrote in message 
>> news:793e$48aa8cdc$4df9b262$14640@news.chello.nl...
>>> Hi,
>>> After six succesful ones, I did  it again... What is the way to remove a 
>>> M2x4 unslitted grub screw from a locked up brass ring? No EDM yet.
>>> Tia,
>>> Dirk
>>>
>>>
>>
>>
> How long will it take Cliff?   I tried the equivalent of sulphuric acid to 
> get a piece of 3mm drill out of Aluminium and gave up after a long 
> weekends worth of messing about.
>

It depends how warm it is, how often you replenish the alum as it is 
exhausted, how well you de-grease the screw, etc. but about a day should do 
it.

Cliff.

"Cliff Coggin"  schreef in bericht 
news:RFyqk.21064$QP4.18381@newsfe19.ams2...
>A solution in water of potassium alumium sulphate, commonly known as alum, 
>will dissolve the steel without affecting the brass.
>
> Cliff Coggin.
>
> "PG1D/PA-11Ø12"  wrote in message 
> news:793e$48aa8cdc$4df9b262$14640@news.chello.nl...
>> Hi,
>> After six succesful ones, I did  it again... What is the way to remove a 
>> M2x4 unslitted grub screw from a locked up brass ring? No EDM yet.
>> Tia,
>> Dirk
>>
>>
>
Cliff, can this "alum" by accident  be found in fertiliser?
Dirk

On Aug 19, 10:03 am, "PG1D/PA-11Ø12" 
wrote:
> Hi,
> After six succesful ones, I did  it again... What is the way to remove a
> M2x4 unslitted grub screw from a locked up brass ring? No EDM yet.
> Tia,
> Dirk

Or you could try a carbide drill, rigid setup, drill at af size plenty
of coolant so you drill the centre of the screw out, then you have a
chance with a square tapered punch in the hole and turning or just
collapse the remains of the screw.
Peter

"PG1D/PA-11Ø12"  wrote in message 
news:9880b$48ab0fc3$4df9b262$10629@news.chello.nl...
>
> "Cliff Coggin"  schreef in bericht 
> news:RFyqk.21064$QP4.18381@newsfe19.ams2...
>>A solution in water of potassium alumium sulphate, commonly known as alum, 
>>will dissolve the steel without affecting the brass.
>>
>> Cliff Coggin.
>>
>> "PG1D/PA-11Ø12"  wrote in message 
>> news:793e$48aa8cdc$4df9b262$14640@news.chello.nl...
>>> Hi,
>>> After six succesful ones, I did  it again... What is the way to remove a 
>>> M2x4 unslitted grub screw from a locked up brass ring? No EDM yet.
>>> Tia,
>>> Dirk
>>>
>>>
>>
> Cliff, can this "alum" by accident  be found in fertiliser?
> Dirk

I don't know about fertiliser, but it is used to turn change the colour of 
pink hydrangea to blue.

Cliff.