Dear All
Favorita was almost right in her explanation.
And copelandci's explanation is even better and I strongly agree with that.
quote...
In contexts you are referring to a large threaded bolt, am I correct? If this is your meaning then you are correct that they are roughly the same thing however a bolt will hold a lot more weight than a screw, and cannot be driven in with a screw-driver but rather with a ratchet.
.....unquote
I would also add that a bolt can also be driven with a spanner and/or with a ratchet handle with a socket.
For further reference please see at
http://www.bahco.com/files/04-0439_S...bpnhhrddku.pdf
I hope it helps
Saludos a todos
cranesfreak