Not to rub finger over file
Not to rub finger over the work piece
To apply equal pressure on file
To support file properly
It will wipe off easily
The line will be too wide for accurate work
The line will smudge and difficult to see
The lines will remain on metal even after good rubbing
More
Less
Same
None of these
Half centre
Pipe centre
Square centre
Revolving centre
Cutting smooth collars
Under cutting
Roughing the surface for hand grip
Enlarging hole size