Jim Wilkins wrote:
On Apr 6, 7:33 pm, David Billington
wrote:

After using a file for many years I was shown by one of my engineering
workshop instructors, when he saw me filing a radius, how to file a
radius correctly and it made the world of difference to the outcome. I
thanked him but have often wondered why such basic information was not
taught as standard, maybe it was thought we didn't need to know that
sort of thing because of the courses we were on and it way too basic.
It's not something I have ever run across in a book either but have not
looked specifically for it.


I was taught to scribe the curve, file a 45 bevel, then cut down the
points to an octagon, then cut those, etc, keeping the flat widths
equal, just like planing a wooden ship spar round. The first cuts were
with a rasp, the last with a single-cut "hand" or "pillar" file.

What is your method?

Jim Wilkins

I've done the same but I was thinking of filing the final smooth curve.
On say a 90 degree corner and holding the piece with each face at about
45 to horizontal what I did originally, as I had never been shown, I
just moved the file forward and rocked it from the near face to the far
face so the contact point travels away form you to create the curve. The
instructor showed my to start with the file parallel with the far face
and moving the file forward, rock it back, to end the stroke with the
file parallel to the near face, in this way the contact point travels
back towards you during the operation. This instantly gave me a much
better finish and radius and it's the way I've done it ever since..