[TheForge] File Making

[GRAF]

I may be exposing my ignorance here, but my understanding was that the 
length of the heat in case hardening affected the depth of the carbon 
enrichment.
If the concern was hardening the sharpened edges on the file there is 
not much to be had in terms of depth at that point.

Might that be part of the answer?

Mike Graf

wmullett at bright.net wrote:
> Thanks David,
>
> I had wondered about the time of exposure to this possible carbon source.  A video of Wallace Cussler making a flint lock shows him case hardening the lock by placing it in a crucible filled with carbon (burned bone I think) and heating that in the forge for a period of time.  Much longer than the short period of time we see in this video on files.
>
> But ... as far as protecting the teeth from the heat process .... that doesn't jive with what I saw.  It appears that they bring the file to a bright red heat before they dip it in the "carbon" and then re-expose that to the heat source.
>
>  
> ============================================================
> From: "David E. Smucker" <davesmucker at hotmail.com>
> Date: Wed Mar 19, 8:59 AM
> To: "AAA TheForge AAA" <theforge at mailman.qth.net>
> Subject: [TheForge] File Making
>
> There is a very interesting section on file making in the book, Metal 
> Working  A Book of Tools, Materials and Processes for the Handyman by Paul 
> N. Hasluck.  Original USA copyright date of 1907, but it is a British book 
> and author and predates this USA date by a number of years.  Lindsay 
> Publications, Inc. has a reprint of this book.  It is about 760 pages with a 
> good index.
>
> It details the tools and methods for hand cutting of files.  The steel being 
> used is high carbon plain steel and the teeth cut in the annealed state.
>
> Here is part of what it says about the heat treating:
>
> "Previous to being hardened the files are drawn though beer grounds, yeast 
> or other sticky matter and then though common salt mixed with hoof parings 
> previously roasted and pounded;  this compound protects the delicate teeth 
> of the file from direct action of the fire, and serves as an index of 
> temperature, as on the fusion of the salt the hardening heat is obtained; 
> also the files are less liable to crack or clink on being immersed in the 
> water."
>
> Now the "roasted and pounded hoof parings" were a common source of very 
> clean carbon so some carbon would for sure be present in the mixture. 
> (Yeast / sugar too is mostly carbon) but my understanding is that the steel 
> used was always high carbon for hand making of files.  This mixture would 
> provide some case hardening effect, but the time of contact is short. (Case 
> hardening is contact time dependent for depth of carbon into the steel.) 
> It seem much more likely to me that the function is to protect the teeth, 
> prevent decarburization and as noted give a good measure of critical 
> temperature.
>
> Dave Smucker
> Brasstown, NC
>
> ps, still having problems sending to theforge, this is a resend.
>
> ----- Original Message ----- 
> From: <wmullett at bright.net>
> To: "Sponsored by ABANA" <theforge at mailman.qth.net>
> Sent: Wednesday, March 19, 2008 7:57 AM
> Subject: Re: Re: [TheForge] Re: File making in Japan
>
>
>   
>> Andy didn't say this was not case hardening - he said modern files are 
>> hardened in lead.  That's not what is happening here.  This is a hand cut 
>> file process using old methods and it still looks like case hardening to 
>> me.
>>
>>
>> ============================================================
>> From: "David E. Smucker" <davesmucker at hotmail.com>
>> Date: Tue Mar 18, 7:47 PM
>> To: "Sponsored by ABANA" <theforge at mailman.qth.net>
>> Subject: Re: [TheForge] Re: File making in Japan
>>
>> I with Andy,  I think it is highly unlikely that hand made Japanese files
>> are case hardened.   The Japanese are noted for their very high carbon, 
>> very
>> high quality steels used for hand tools, woodworking blades and such.
>>
>> Dave Smucker
>> Brasstown, NC
>>     
>
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