Vintage Windmill and Wind Generator Forum

Can the metal sails be straightened back to original with a sheet metal roller??

Usually. But it depends on what shape they are in. There was a time when they made brittle sails. Worth a try.

I've had some that were bent and creased. Straightened them out with hammer, rolled through upside down to flatten, then flipped over and rolled the curve back in. Works great, but a PITA removing all rivets and clips.

Drill or use an air hammer to remove clips . Then as ed said reverse the sails and roll it flat then put the curve back. Usually can t get all of the creases out if bent bad but can make a workable sail

I have a slip-roll I use on all sails that are not crimped. You need a reference curvature, though, unless you do all of them. Measure tip to tip.

I also have a favorite log of just the right diameter that I clamp to a sail and hammer with a rubber mallet I split the log down the middle to lighten it. If the sails are still on the wheel, a shorter log section can be clamped to it and then pounded to the exact curvature. Sheet metal / body shop tools are handy for this.

You might try grinding either head off the rivets, and used a broad chisel to separate the items. Then you can finish removing the rivets and pre-straighten the worst creases. then you can re-roll them.
This is what I usually do.