[TheForge] Spring steel (and other) breaking in mild acid

[peter fels]

For some years i used similar devices i'd snagged , broken, from the backs of antique/junke  shops and swap meets and then assembled, to clear the abundant spring growth for fire season. Partly cause i was poor and hard headed and partly cause it was faster and more effective that the flimsy weed wackers then available. My back was better then.
The old, hand forged, broad bladed ones were most effective, if the most work to swing....and following the advice to be had from old books and curmudgeons, i cross peined the edges to the point where a few swipes longitudinal of a  recommended abrasive baton made a reasonably sharp, toothed edge.
The blade seemed to need the work hardening to hold an edge, and the softness to survive the odd rock encountered. Too much hammering lead to splits and chips. Not enough and the more siliceous native  grass stems dulled it quickly.
I could outmow my friend with the  2 cycle weed wacker for about 2 hours...then i sat down and panted a lot. The last good 2 handled scythe hangs on the shop wall now.
I am too old and no longer horny enough to even consider autofrotting an artillery orifice. Never my type anyway.
On Aug 27, 2011, at 2:51 PM, Mike Spencer wrote:

> 
> Andrew Vida <osan at netlabs.net> wrote:
> 
>> AKA work hardening... similar to autofrettage in artillery barrels...
> 
> I read that as "autofrottage in artillery barrels". What you get for
> sharing an artillery barrel with somebody else. 
> 
> Never heard of autofrettage.  Thanks for the new word.
> 
> I spent most of today at a hand mowing competition.  I wanted to see
> if I could pick up some pointers on my style but mainly I wanted to
> learn about "peening a scythe blade".
> 
> The serious competitors use blades broader than those normally sold in
> farm supply stores.  It appears that the latter are drop forged while
> the former show signs of some degree of hand forging.  All the ones I
> looked at were made in Austria and were quite thin. As well, they
> showed little pukky marks of being hammered all over on the top surface
> with an almost pointy hammer.  I'm guessing that this hand-, air- or
> treadle-hammering is done to cause the slight dishing visible on
> blades so marked.
> 
> But that's not the "peening" deal.  To obtain the finest edge, the
> blade is place on a polished cylindrical little stake anvil (axis of the
> cylinder parallel to the edge) with the edge very near the crest of the
> anvil's curve.  Then it's hammered firmly but not very hard with a
> polished crosspeen *very* near the edge.  The orientation of the anvil
> and and hammer are such that the metal is drawn toward the edge but
> not (very much at all) along the edge (which would lead to totally
> unacceptable rippling.)  All done cold.
> 
> The guy giving me the tutorial said that most typical North American
> blades won't respond well to this treatment but that the Austrian
> blades can be peened to an edge so thin that it can be flexed slightly
> with a thumbnail. He didn't make the edge of his demo blade quite that
> thin but almost. And there was no visible rippling.
> 
> All very interesting. Nobody at the meet (that I talked to) had any
> hard metallurgical facts about the alloy or factory heat treating on
> these Austrian blades.
> 
> I have a regular store-boughten blade of the probably-drop-forged
> variety with which I'm only moderately proficient compared to the
> better competitors at the meet.  I also have a wide one with elaborate
> (but not readily readable) maker's marks that's clearly hand forged --
> there are obvious fuller makes near the heel and other details.
> 
> So now I'm going to have to see what I can do about fixing my blades
> up to work as well as the ones the competitors use.
> 
> Another feature of the competition was the remarkable variety of
> custom snaths and nibs, most of non-adjustable but made to fit the
> stature of the owner, in both bent and welded aluminum and in finely
> crafted wood.
> 
> - Mike
> 
> -- 
> Michael Spencer                  Nova Scotia, Canada       .~. 
>                                                           /V\ 
> mspencer at tallships.ca                                     /( )\
> http://home.tallships.ca/mspencer/                        ^^-^^
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