Generally a scramble is a climb up to Mod grade or so, for msot will not require a rope. I think soloing is mroe a case of a climb where to be safe you really should have a rope?? Its a funny one really. Suppsoe its down to your own interpritation of it. A scramble to me is an easy climb I wouldnt need to rope on. So soem grade 3 scrambles I dont know if I would call them a scramble so much as a rock climb, butthen the elvel of climbing is too easy to be caleld a climb, but the exposure warrants a rope. Its complicated isnt it.
I think whether to use a rope or not is a very individual decision (both in terms of individual people and individual situations) and so it's slightly pointless to try and identify particular routes or grades where a rope is needed. It's a matter of judgement in every case and is influenced by a very large number of factors. I can see why the books make recommendations, of course, but it's so variable and individual that it's hard to make rules about this. The only rule I really have, personally, is that if one member of the team feels the need for a rope then you use a rope - without quibbling. Unless you haven't got one. Then you need to refer to rule 1(a) - i.e., panic.
I think differentiating between scrambles and climbs is actually not that hard:
Grade 1 and 2 - scrambles Grade 3 and 3s - scrambles and climbs (overlapping systems so fits into both) Mod and diff - scrambles and climbs (overlapping systems so fits into both) VDiff and above - climbs
A scramble is a climb, its just a relativley easy one.
The question of when does a scramble become a climb is no different to asking when does a "Diffiuclt" become a "Severe" Its just a question of one being a bit harder than another. They could just as easy be called 1,2,3,4,5,6,7.
A decisison to use a rope depends on your own skill level in relation to the grade of climb and local conditions on the day and your own judgement.
just saw this and thought to myself a scramble becomes a climb when the scrambler needs a rope , could be easy to a climber but might be severe to the uninitated ... this is true as i have done lots of so called easy scrambles but when taking friends sometimes a bit of climbing saftey knowledge comes in handy . enjoy yourself anyway ....