The Origami Forum

Hi. I'm trying to complete this diagram - http://www.ulster.net/~spider/oldhat.gif, but I'm having trouble understanding step 7. I can't find anything on the internet that explains what a hinge fold is, and I'm not too sure how to sink fold in the context of this diagram, but I may be able to figure it out if I know how to hinge fold. Can anyone explain to me what it it is? Thanks.

I never heard of that kind of fold, but I'm pretty sure it looks like a closed sink. I just think that you have to mountain fold the base of the hat as in step 7 before doing the sink.

Thanks. Which bit do I mountain fold?

I folded this model and the hinge-fold is actually just a simple closed-sink...

OK thanks I'll give it a try.

I once saw the term hinge fold referring to a swivel fold, but this does not seem the case

Actually I think (also looking at the symbols) that a hinge fold in this case is just a weird term for prefolding in both valley and mountain direction, i.e. moving the flap back and forth like a door in its hinge.

It says, "Hinge fold, then sink", so you precrease in both directions and then do a (closed) sink.