Speed of reformatting large file

Hi,

I have a file which contains about 45000 lines of 50 characters each. I want
to reformat it to contain 60 characters each.

I can read the whole file in and remove the line endings and then print out
lines of 60 characters, but this can take some time. And I may need to do
this on bigger files still.

Is there a quicker way?

Thanks for any help

Adam