Posted by Mark Rand on 05/08/2018 22:20:25:
Note:- Bastard files are between coarse files and second cut files. Bastard files are fairly rare these days. Coarse files are an endangered species.
Must admit you are quite correct, think it was the demise of the quality tooling over previous decades leaving a few producers calling them bastards when more like a courser second cut.
Last genuine bastards available in bulk must have been around 2002/3, there on after impossible to find a decent cutting file or one that lasts 1/4 as long pre 2002.
Dreadnought

Millenicut
As above millenicut are straight teeth though can be angles like this.

Or like this Millenicut again.

Any file will scratch think about it, even a though proud over the whole file will scratch! They were only working with thin guage materials as well. You wont get even close to 10 thou with a millenicut yet alone file to sub thous!
Think that term millenicut used on aircraft is nonsense, most of the people didnt know how to use a file just learnt as they went on. In this case take a look at the last millenicut, will see the teeth are straight but angled- what that means is to mr average joe blogs is theyre pushing straight ahead right or wrong but the file effectively moves diagonally!
Now a tricked up filer can do that with any file just feeling for whats happening, cant teach that. Also this can and has been used to the filers advantage in clearing debris ie swing right to left in a scraping motion until starts to pick up, then opposite swing may or may not dislodge whilst also taking a cut.