Hand Tools Archive

Subject:
Re: outside of your back and forth..

Jérôme
> ...with larry and mention of the double iron, I saw only two references anywhere else to practical use of the cap iron before 2012.

As you often say yourself, "I am not trying to sell anyone anything", but I find old books interesting and google books allows us to access some ancient knowledge, such as "manuel du tourneur", 1796, by Louis Salivet, a Roubo contemporary. In this book, he attributes the double iron to the Germans and recommends to set it so that the iron protudes "imperceptibly", at most "quarter of a line" (1/12 of a French inch, say less than .5mm). He mentions that the double iron must bent square then honed to meet the blade (That would represent a final ~80° angle ?).
The expected benefit is explicitly to reduce tear out.

He also goes on to mention that one can get the well prepared adjustable screwed iron+double iron sets at “Bergeron". This could mean that the practice was well known at the time.

See https://books.google.fr/books?id=Ssk9AAAAcAAJ&dq=Double%20fer%20rabot&hl=fr&pg=PR3#v=onepage&q=Double%20fer%20rabot&f=false

In a more recent book (https://books.google.fr/books?id=Zu0OB-uKo8MC&dq=Contrefer%20rabot&hl=fr&pg=PA181#v=onepage&q=Double%20fer&f=false), the author says that for difficult woods, with a wooden plane, the wedge could be inserted between the iron and the cap iron, as to increase the angle. But he also goes on to find this technique too inconvenient. He also mentions that the tip of the cap iron is "rounded" (unicorned maybe ?)

On the other hand, Roubo only describes single iron planes, smoothers featuring a 60° frog and a 0.5mm mouth. Also metal sole bevel up shooting planes, and lots of scraping planes.

There are also many old patents, French, German, English ..., that describe and illustrate "concepts planes", with adjustable frog angle, metal pieces, etc. They also describe the expected benefits of their invention compared to their era "standards".
I find it fun that some predicts that "no arm could ever swing an all metal plane all day" :)

Again, I am not giving advice or opinion, I just share links to publicly available treasures.

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