Well, I don´t know if the response by Billman was directed to me, but there are several points to answer.
I never said that the machetes were pre-hispanic. Obviously they were not, since there was not iron metallurgy in America as to make this kind of blades. Tough initial development of some kind of iron working in some American pre-hispanic areas is actually discussed, it is without doubt that iron weaponry came with the spaniards, and this a too well known fact. What I said, is that they were Spanish-colonial, which is a very different matter. Of course, the machetes, or some of their components, were manufacturated just latter in the American colonies.
On other side, there is a contradiction in saying that the machetes were used in whatever is uderstood by some authors as "Central America" (singular), and saying that the early word used to designate this item was "matchet", as it does not come from any Spanish or native American word; and in this specific philological matter I prefer the studies made by spanish-speaking scholars. If in english this word was, or is, used, it is irrelevant to the purpose of establishing the origin of the word machete itself, as this last word was forged from the spanish castilian and has no traces of American indian roots. Maybe the original word from the castilian was mispelled or misunderstood when passed to the english in some era, after the 16th century, as it was often in castilian with many names from other languajes. Or maybe there was another weapon known as matchet somewhere else.
As far as I know, the machete is not as old as the 16th century, at least with this name. It is not included in any relation, reference, inventory, law, guild regulation or Spanish document from that epoch, or in the actual researches made by the Spanish scholars on this subject about that epoch. I would like to see any research or primary source in english about machetes from the 16th century, apart from actual third party references. Of course, in english some authors make their own studies and classifications of the Spanish colonial weapons, more often than not having any knowledge of the Spanish sources, or even any knowledge about the spanish-castilian languaje, so that naturally great gaps and strange classifications and misunderstandings appear, as in the case of the so-called "Caribbean Rapier". And very recently enough on this forum some machetes (they were believed to be swords) were a mystery and no reference was found among the english-speaking authors or scholars about them, and speculations were made about their origin in all the continents except Europe. Of course there is a lot of research to do. But first it is necessary to know the actual, existing, sources in other languajes, and there are MANY books and articles about Spanish, Spanish-colonial and Latin American Weapons which are not read in the anglo-saxon world due language-related problems.
Speaking of the Portuguese, it is known that Portugal was once part of the Spanish Empire. I don´t know to a which point the Portuguese weapons were influenced by the Spanish, since I don´t have knowledge about the Portuguese weapons, but for a minumum. In this sense, I also don´t know if the use of the machete among the Portuguese came from the Spanish people, or from other source, but this last case is unlikely.
The machete has much of a relation with the labour in the field, no matter if the workers were slaves or not. I must state that the use of slavery in Mexico AND Central America was not intensive, and though some black decendants do exist today, already much mixed with indians and the so called "caucasian", they are few. In the case of other Latin American countries is a different case. Cuba in the Spanish Caribbean, Peru, Colombia and Venezuela, and also the portuguese Brasil, those last in South America, were cases of a much more intensive use of the black slave labour. The presence of black people in Panama (Central America) came from South America. But the use of the machete was also very widely difussed, and still is, among the aboriginal indians (again: this, does not remotely mean that they had machetes before the arrival of the Spaniards) and in general among all the rural population.
There is also a contradiction in saying that the first machetes were from the 16th century, and saying that it is not actually known if the first machetes were made locally in "Central Americas" (whatever that means) or in in the "home country", since in other part of this post is said, accurately, that in this time America has not a developed iron-steel metallurgy, and I must add, not even from meterorites. Of course the first machetes were made on Spain. There is no doubt about it. At least, not among the spanish speaking people. Although the city-state Tenochtitlan was conquered at the beginning of the 16th century, the rest of the conquest lasted at least the rest of the 16th century and there was no Spanish production of blades in Mexico in that time, and less in Central America, mostly unexplored. Perhaps Spanish blades were rehilted or modified if broken to make smaller weapons. The older references we have about the machetes, among others, come from old royal ordinances regulating their extensive use in the Spanish army, when machetes were already well known there from time ago. The first known models were items with handguards and very diverse forms of blades, not having other thing in common but for beign shorter than a Spanish sword of that time. Not a specific morphology in any way, except for the size, and they could be shorter versions of swords, without resemblance to the latter machetes.
Also, the resemblance of the machete with the naval cutlass is just that, and the naval cutlass also it is not a product of the 16th century or before (the century given by the reference), as to be the ancestor of the machete. There is no genealogical relation. The Spanish navy had not, as far as I know, any regulated patterns of naval machete before the appearance to the first models, and the older ordinances about this subject are established extensively just for the army forces (on land, of course), probably before the appearance of the cutlasses. Any of the very diverse forms of earlier machetes does not resemble a naval cutlass, especially in the forms of the hilts. There are extensive articles about this machetes, and books where they are referenced and illustrated. And speaking about their ancestry, Spain had its own long tradition with this kind of shorter weapons, specially from arabic influence, as the terciados and the so-called alfanjes and scimitars, though those last two terms only generically designated in Spanish shorter weapons, some of them curved, and as I see it there is no actual agreement about all their specific forms. In any case, part of actual Spain was dominated by the Arabs to the 15th century, a fact which gave to the Spanish kingdoms the opportunity to have both all the influences form Europe, and those from Nort Africa and the Middle East, which was reflected on their weaponry and tools. On other side, the very close relation of the terciado with the alfanje and machete was already established by German Dueñas Beraiz, one of the main living scholars on Spanish weapons, in his "Introducción al Estudio Tipológico de las Espadas Españolas: Siglos XVI Y XVII" (Introduction to the Typological Study of the Spanish Swords: 16th and 17th Centuries) , in Gladius, No. XXIV, 2004, pp.209-260. This article is open in the site of Gladius. There are also some articles about ordinance machetes of the Spanish Army in this website, to which years ago I already posted a link in this forum:
http://www.catalogacionarmas.com/index.asp
I could also post an original bibliography on Spanish weapons, including the machetes, although of course, all this material is writen in spanish language. There is a lot of research on this sources and not speculation. There are, also, the open sources like the indispensable Gladius, which can be consulted for free in internet, with some articles written in english and french, though most of them in spanish.
On the other side, the Spanish had no much contact with South Asia, except through the Portugese, but there is no evidence whatsoever that the south asian weapons and tools have influenced to a minimal point the Spanish production, and none of the abundant sources remotely consider this possible influence. All this, despite the existing trade with wootz from India to Spain to the mid-19th century.
The bill hooked blades never were called "machetes" in America. They do were used, but recived other names. In Mexico, they are still used in working with the magueyes (agaves from which are extracted fibers, honey of some kind consumed as beverage or fermented to make pulque, an aboriginal alcoholic beverage, and from their hearts is also extracted by boiling a liquid which properly destilated produces mezcal and its specific variety named tequila)
Finally, I only need to emphasize that I said before that the machete AS WE ACTUALLY KNOW IT, probably comes from a Mexican-Central America development, though a development made from Spanish-colonial era which latter evolved in specific local models or variants, some of them very large in relation to the original and as long as a saber, though the Royal Academy of the Spanish Language still continues to define the machete as a short edged "heavy" weapon (meaning: shorter than a sword or saber).
Ref: Tempering
Blades can, and are, actually tempered in molten lead by bladesmiths, although of course the lead is aloyed with tin to produce a lower point of melting, since the temperature of 350-400 centigrades could be undesirable, depending on the kind of steel. Anyway, this procedure is normalyy called "tempering in lead" and the word "alloy" is usually implied, as it is also when we refer to the steel with this single word, no matter if it is aloyed or not with other metals, and so I think the reference made by Rick is accurate. More normally, hardening-quenching is made by heathing the steel in a forge or oven and then cooling in water or oil at room temperature, though in a serial process the water or oil warms after several quenchings and they must be cooled. Latter, tempering is made heating usually up to the 250 centigrades AND ABOVE 260 centigrades. But what I meant, is that the red-heated steel could be also cooled in molten lead alloy (or in a salt bath) slightly above its point of melting calculated for this alloy in the 250 centigrades (though the alloy would be mostly tin), so the blade could be hardened and tempered in the same operation. It can work fine to get a flexible blade not too hard to be brittle. Heat treatments as quenchin-tempering are made at HIGHER temperatures (for example, in the range of the 250-300 centigrades and even SLIGHTLY above, lets say. during three hours, for a 5160 steel) to get bainite instead martensite (austempering) in other alloy with a bigger content of lead. This procedure has become popular among recognized anglosaxon bladesmiths not many years ago, although most of them use hot salt baths due several reasons, since it permits: to obtain enough good hardness, supressing at the same time the risk of broken or cracked blades produced sometimes during the usual quenching-hardening; to minimize or supress the scab produced normally on the surface of the blades quenched-hardened through the usual process (which is a tedious problem to clean by file and sand, even with power bandsanders); to produce a tough blade difficult to breake under stress; to get less deformations on the blades than those produced by the usual process of water-oil quenching-hardening, and to eliminate the need of a further tempering. This is why I wrote about wondering if the blades were "hardened" or "tempered" in the words quoted by Rick, since these words can carry different meanings in terms of temperature of the alloy and since the blades could be tempered after quenched, or in the same step it could be obtained both results by dipping in molten lead (alloy) from 240 to 300 centigrades, as the blade gets its martensite or bainite hardness, and also its temper. Temperatures below the 100 centigrades can also be recommended to quench some steel blades, but in this case warm oil is used and further tempering is made. I only wondered about the specific word without further complicated explanations, as I don´t have much time to connect to internet and my post was already long at that moment (this one I better made it in home to avoid at least many undesirable mistakes).
So, my comment to Rick was originated in my need to know which procedure used Collins, and IT WAS NOT A CORRECTION to him. I apologize to Rick by my unclear comment. This is also why latter in the week I wrote him privately a message, asking for more information, as it can not be excluded the possibility that Collins even worked to get bainite instead martensite, as I believe it is not a modern process, as some bladesmiths claim. And this is interesting for me because, as an amateur, I make long blades and also have interest in the history of the metallurgy related to the edged weapons, especially in the presence of so many unclear areas related to their chemical and physical properties and elaboration procedures.
Thank you for your attention
Regards
Gonzalo