Will SK1 front fork springs fit a curvy?
 

Well.....will they? And what is meant by progressive springs? I would have thought all springs were progressive.

Yes.

Progressive srpings are not single rate springs, they compress at different rates at different parts of the coil.
Most of us prefer single rate springs.

Re: Will SK1 front fork springs fit a curvy?
 

A K1 is a curvy, all springs for curvies will fit all curvies*, but they must be fitted with the appropriate spacers and spring seats, to suit the caps or adjusters.

Progressive springs are wound with close coils at one end and wider spaced coils at the other end, the purpose of this is to have softer springing for smaller for smaller suspension movements, and stiffer springing for larger suspension movements.
Progressive is a brand as well as a description of the spring type.

*And some, (at least), pointies too.

I'll get me coat!

Why do people not like progressive springs?