It is really only to clean up the surface to remove any marks from when the metal was drawn /rolled or to remove machining marks.

A fine file is held across you and moved to and fro along the work so the file is cutting sideways. This will give quite a nice finish, if you want finer you can then wrap emery cloth around the file and use it in the same way

Use a single cut file, not a double cut one. The latter will tend to produce fine ridges in the work while the former produce a smooth finish.

The action is shearing rather than cutting.

Draw filing was the only finish allowed when I was training nearly sixty years ago. Filing can keep the edges and faces square, emery puts a softer face in contact which will round the surface.

Beware of “pinning” the file: i.e. tiny filings becoming wedged in the gullets.

They act as fangs, scratching the surface.

Keep the file clean, and (I recall being taught at school!) rubbing blackboard chalk into the file will reduce the risk. Don’t use natural chalk rock as that can contain tiny flint or sand grains that will damage the file as well as the work.

I have not tried it but talcum powder might be as effective… as well as giving you a rather sweet-smelling workshop!

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How to clean the file to remove “pins”? Not with a steel wire brush. Take a scrap of brass and push its edge into and along the teeth (so across the file). It will partially take on the gullet profile and push the swarf out without trying to blunt the teeth.

I sometimes use white spirit or WD-40 (mainly white spirit anyway) or thin lubricating oil when draw-filing. It seems to reduce pinning and give a finer finish, but this might be my perception – or luck.

Draw-filing is a skill worth cultivating as it can give a lovely satiny-brushed finish on mild-steel especially, and on a model sometimes looking more prototypical than polishing would.

No. A Mill-file, or milling-cut file, has a single row of straight of curved teeth, but is very coarse.

Draw-filing uses a Second-cut or finer, grade.

Blackboard chalk will do, but a stick of french chalk is perhaps better.

Don’t worry, Duncan … you were right

https://www.classichandtools.com/vallorbe-10-blunt-mill-file-single-cut/p1269

https://benchmarkabrasives.com/blogs/news/difference-between-a-mill-file-and-a-flat-file

… I think it’s the good old English language that’s struggling again.

’Mill File’ is not the same as ‘Millenicut File’

https://www.wonkeedonkeetools.co.uk/files/what-is-a-millenicut-file

MichaelG.

Hi, I guess it all depends on local terminology, I’ve always known the type I’ve shown as milling cut, however, Buck & Hickman called them Milled Tooth, and the particular one I’ve shown, is a Dreadnought, and the finer toothed one a Millenicut.

Cromwell also call them Milled Tooth.

While looking through the Cromwell catalogue that I have, I found this.

Which relates to the fairly recent discussion about Python file handles, and shows a really good picture of the spring and it’s location inside, and the relative length of the file tang.

Regards Nick.