OldTools Archive

Recent Bios FAQ

157698 "James DuPrie" <jduprie@c...> 2006‑03‑03 RE: Refurbishing files (long)
Way cool! Now where does one go about scoring sulfuric acid with a SG of
1.250?

--JD

-----Original Message-----
From: oldtools-bounces@r...
[mailto:oldtools-bounces@r...] On Behalf Of Peter B
Sent: Thursday, March 02, 2006 11:08 PM
To: 'Old Tools List'
Subject: [OldTools] Refurbishing files (long)

Greetings all from warm, humid NSW Australia,

I found this article in the May 12th 1955 Model Engineer magazine (I'm a 
tad behind in
my reading backlog!!!)

Was sumbitted by 'Bud' of Oakland Ca.

'Procure some sulphuric acid of about 1.250 specific gravity...........
Procure an earthenware or glass pan large enough so that the files can 
be placed flat on the
bottom..........
Clean the files with a file card or wire brush. I use a needle to flick 
off any metal particles
stuck in the grooves.
Place the files in the pan and pour in the 1.250 S.G. acid solution 
until they are covered.
Or the acid  can be poured in first .......
Very shortly small bubbles will form on the files as the acid eats into 
the grooves.
If this does not happen within five minutes the acid is too strong. 
Simply pour in
more water (!!!!!!) and stir.
The entire secret of sharpening files is to use weak sulphuric acid, 
since weak acid
eats steel, whereas strong acid does not.
Leave the files in for a couple of hours and then feel them to see if 
they are sharp.
Very dull files that are almost smoothe should be left in for eight hours.

When the files are really sharp, remove from acid and wash thoroughly in 
water.
When they are dry they will have a slightly brownish tinge and unless 
given a coat of oil
will rust rapidly................

(Safety with acid mentioned here re pouring acid into water not water 
into acid, it will
eat clothes with the exception of wool, fumes are dangerous)
Bicarbonate of soda (baking soda) solution will neutralise sulphuric acid.
1 tablespoon per quart of water solution is useful.

The 1.250 S.G. solution can be reused. Pour the acid solution out of  
the pan into
a glass jar leaving the black residue in the pan to be washed out.....

Do not take files out too soon. It is better to leave them in too long 
than not long
enough. They may feel sharp but are actually not etched deep, and if 
taken out
too soon will become dull after a short time.

After you have sharpened the same file for 20 years (!!!!!) it will 
become so thin
that you can bend it around in a circle (!!!!!!) '

So, dear readers, that's it, all you ever wanted to know about acid 
sharpening
of files.
I make this disclaimer:-
I have merely written in part someone else's ideas on the subject.
I take no responsibility for any accident, mishap or injury caused to anyone
using this information. ACID IS DANGEROUS!!!!

Peter B

------------------------------------------------------------------------

157702 "Rodgers Charles" <RODGERS_CHARLES@b...> 2006‑03‑03 RE: Refurbishing files (long)
JD responds to Peter B's tutorial on acid sharpening of files by asking:

> Way cool! Now where does one go about scoring sulfuric acid with a SG
of 1.250?

Well, any auto parts store should be able to fix you up.  Flooded lead
acid batteries use sulfuric acid for the electrolyte.  Straight sulfuric
acid has a specific gravity of 1.8, so you can add distilled water to it
until it reaches 1.25...just buy a decent hygrometer and pay attention
to the temperature compensation chart.
Charlie Rodgers
Clinton, Maryland

------------------------------------------------------------------------

157703 "Rodgers Charles" <RODGERS_CHARLES@b...> 2006‑03‑03 RE: Refurbishing files (long)
Obviously, that should be a hydrometer, not hygrometer (measures
mositure content of a gas).. 
Charlie
-----Original Message-----
From: oldtools-bounces@r...
[mailto:oldtools-bounces@r...] On Behalf Of Rodgers
Charles
Sent: Friday, March 03, 2006 8:51 AM
To: James DuPrie; Peter B; Old Tools List
Subject: RE: [OldTools] Refurbishing files (long)

JD responds to Peter B's tutorial on acid sharpening of files by asking:

> Way cool! Now where does one go about scoring sulfuric acid with a SG
of 1.250?

Well, any auto parts store should be able to fix you up.  Flooded lead
acid batteries use sulfuric acid for the electrolyte.  Straight sulfuric
acid has a specific gravity of 1.8, so you can add distilled water to it
until it reaches 1.25...just buy a decent hygrometer and pay attention
to the temperature compensation chart.
Charlie Rodgers
Clinton, Maryland

------------------------------------------------------------------------

157711 "Clay Risenhoover" <crisenhoover@s...> 2006‑03‑03 RE: Refurbishing files (long)
Don't know if this helps any, but Electrolyte Grade sulfuric acid is
1.265 SG usually, so it wouldn't take much water to cut it. This is the
sulfuric acid used as electrolyte in lead acid batteries like car
batteries. I've never tried to buy any though... 

-Clay

-----Original Message-----
From: oldtools-bounces@r...
[mailto:oldtools-bounces@r...] On Behalf Of James
DuPrie
Sent: Friday, March 03, 2006 6:41 AM
To: 'Peter B'; 'Old Tools List'
Subject: RE: [OldTools] Refurbishing files (long)

Way cool! Now where does one go about scoring sulfuric acid with a SG of
1.250?

--JD

-----Original Message-----
From: oldtools-bounces@r...
[mailto:oldtools-bounces@r...] On Behalf Of Peter B
Sent: Thursday, March 02, 2006 11:08 PM
To: 'Old Tools List'
Subject: [OldTools] Refurbishing files (long)

Greetings all from warm, humid NSW Australia,

I found this article in the May 12th 1955 Model Engineer magazine (I'm a

tad behind in
my reading backlog!!!)

Was sumbitted by 'Bud' of Oakland Ca.

'Procure some sulphuric acid of about 1.250 specific gravity...........
Procure an earthenware or glass pan large enough so that the files can 
be placed flat on the
bottom..........
Clean the files with a file card or wire brush. I use a needle to flick 
off any metal particles
stuck in the grooves.
Place the files in the pan and pour in the 1.250 S.G. acid solution 
until they are covered.
Or the acid  can be poured in first .......
Very shortly small bubbles will form on the files as the acid eats into 
the grooves.
If this does not happen within five minutes the acid is too strong. 
Simply pour in
more water (!!!!!!) and stir.
The entire secret of sharpening files is to use weak sulphuric acid, 
since weak acid
eats steel, whereas strong acid does not.
Leave the files in for a couple of hours and then feel them to see if 
they are sharp.
Very dull files that are almost smoothe should be left in for eight
hours.

When the files are really sharp, remove from acid and wash thoroughly in

water.
When they are dry they will have a slightly brownish tinge and unless 
given a coat of oil
will rust rapidly................

(Safety with acid mentioned here re pouring acid into water not water 
into acid, it will
eat clothes with the exception of wool, fumes are dangerous)
Bicarbonate of soda (baking soda) solution will neutralise sulphuric
acid.
1 tablespoon per quart of water solution is useful.

The 1.250 S.G. solution can be reused. Pour the acid solution out of  
the pan into
a glass jar leaving the black residue in the pan to be washed out.....

Do not take files out too soon. It is better to leave them in too long 
than not long
enough. They may feel sharp but are actually not etched deep, and if 
taken out
too soon will become dull after a short time.

After you have sharpened the same file for 20 years (!!!!!) it will 
become so thin
that you can bend it around in a circle (!!!!!!) '

So, dear readers, that's it, all you ever wanted to know about acid 
sharpening
of files.
I make this disclaimer:-
I have merely written in part someone else's ideas on the subject.
I take no responsibility for any accident, mishap or injury caused to
anyone
using this information. ACID IS DANGEROUS!!!!

Peter B

------------------------------------------------------------------------

157695 Peter B <peter51@h...> 2006‑03‑03 Refurbishing files (long)
Greetings all from warm, humid NSW Australia,

I found this article in the May 12th 1955 Model Engineer magazine (I'm a 
tad behind in
my reading backlog!!!)

Was sumbitted by 'Bud' of Oakland Ca.

'Procure some sulphuric acid of about 1.250 specific gravity...........
Procure an earthenware or glass pan large enough so that the files can 
be placed flat on the
bottom..........
Clean the files with a file card or wire brush. I use a needle to flick 
off any metal particles
stuck in the grooves.
Place the files in the pan and pour in the 1.250 S.G. acid solution 
until they are covered.
Or the acid  can be poured in first .......
Very shortly small bubbles will form on the files as the acid eats into 
the grooves.
If this does not happen within five minutes the acid is too strong. 
Simply pour in
more water (!!!!!!) and stir.
The entire secret of sharpening files is to use weak sulphuric acid, 
since weak acid
eats steel, whereas strong acid does not.
Leave the files in for a couple of hours and then feel them to see if 
they are sharp.
Very dull files that are almost smoothe should be left in for eight hours.

When the files are really sharp, remove from acid and wash thoroughly in 
water.
When they are dry they will have a slightly brownish tinge and unless 
given a coat of oil
will rust rapidly................

(Safety with acid mentioned here re pouring acid into water not water 
into acid, it will
eat clothes with the exception of wool, fumes are dangerous)
Bicarbonate of soda (baking soda) solution will neutralise sulphuric acid.
1 tablespoon per quart of water solution is useful.

The 1.250 S.G. solution can be reused. Pour the acid solution out of  
the pan into
a glass jar leaving the black residue in the pan to be washed out.....

Do not take files out too soon. It is better to leave them in too long 
than not long
enough. They may feel sharp but are actually not etched deep, and if 
taken out
too soon will become dull after a short time.

After you have sharpened the same file for 20 years (!!!!!) it will 
become so thin
that you can bend it around in a circle (!!!!!!) '

So, dear readers, that's it, all you ever wanted to know about acid 
sharpening
of files.
I make this disclaimer:-
I have merely written in part someone else's ideas on the subject.
I take no responsibility for any accident, mishap or injury caused to anyone
using this information. ACID IS DANGEROUS!!!!

Peter B

------------------------------------------------------------------------


Recent Bios FAQ