On Jan 2, 2009, at 1:08 PM, Aongus MacCana wrote:
Hey I see from Stephen Schneider's mail that there is more to this embossing
lark than I thought.
In the act of embossing, you are forcing material UP by putting pressure on the surrounding material. This causes a, for lack of a better phrase than I can come up with, a 'volcano' or a 'rift' effect whereas the material is forced up at the expense of the surrounding material. If one were embossing a reed plate, they would be making the reed plate thinner while at the same time making a thicker area/ portion/structure/design, (add your own semantics).
Two tectonic plates working against each other are an example of embossing. Mountains are an example of embossing.
In the act of indenting..in other words creating an area that is INto the material, you are leaving the reed plate at it's original thickness but pushing a design IN. One can also acquire the required result of INdenting, by means of ENgraving. In that case, you are removing material, (with little effect on the surroundings)
Soo, when a person draws a sharp object along the sides of an opening making a furrow or cut, it would seem that they are embossing. In actuality, they are swaging.
In my simple mind I thought the object of the exercise was simply to spread
the material of the reed plate to reduce the "daylight" between reed and
reed plate. Stephen's reference to forming a ridge suggests that there is
more to the process than that.
In the act of swaging, you are working the material cold. You are forcing the material to go one way by use of pressure. If one were to squeeze the brass in a reed plate (for example) so that it flows, this pressure could conceivably close up the tolerances in any hole in the material. What you are doing is applying pressure evenly and consistently in a given area and making the reed plate thinner in that area with the idea of using the 'scavenged' metal to do your bidding.
Drawing a coin, ball bearing, shot glass across a slot will (cold) swage the sides of such slot and metal will be forced sideways. This will close up the slots size an infinitessimal amount. Infinitessimal is all that you need when working with thousandths.
In the act of forging, you are working the metal hot.
Burnishing is not even remotely related to these other subjects and won't be delved into.
I have to admit that swaging like "drawing under the hammer" is a technique
beloved of blacksmiths, but don't lets knock the blacksmiths. In my happy
days as a post grad apprentice in the national railway works the blacksmiths
used to refer to the tool room machinists and other lesser orders as mere
"blacksmith's finishers"
Which is a silly thing for blacksmith's to say. They do the forging and swaging. It is the rough work. Machinists, grinders, engravers, and burnishers do the finish work. 150 years ago, some mighty fine work was done in France. It wasn't done by blacksmiths. They supplied the roughings. Pennsylvania long rifles (often times called Kentucky rifles), were not made by blacksmiths. Same deal.
smokey-joe
Beannachtai Aongus Mac Cana
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