Straightening bent windmill vanes


I have an old windmill whose vanes are bent up and creased and with bullet
holes- some fairly minor but some with some pretty big bends and creases.
Sorry, don't know the metal gauge but its fairly stout, and the vanes all
have a designed in slight curve. Each vane is about 2-3 feet long and 20
inches wide at the widest part
The question is what methods/tools would be most effective in
straightening: 1) hammer and dollies 2) shop press 3) English wheel 4)
planishing hammer 5) metal shrinker/stretcher. Options 2) thru 5) all
seem to be about the same price range- about $250 at Harbor Fright. And
what would be the second best approach, and which would have the most
follow-on utility for fixing/fabbing things on a small ranch ?
BTW I am aware of where I can buy replacement blades for the worst ones
and heat shrinking with an oxy torch (which I have).
Thanks,
Bob
-------------------------------------
##-----------------------------------------------##
Delivered via
formatting link
Forums
Web and RSS access to your
favorite newsgroup -
rec.crafts.metalworking - 175288 messages and counting!
##-----------------------------------------------##
Reply to
bcarwell
Loading thread data ...
You should have three types of vanes. Some good ones, some with holes and some with bends. Do this:
Take all the vanes off the wheel. make a stack of good vanes. When all done, you will need to distribute as evenly as possible, the good vanes with the repaired ones.
The vanes with holes can have the holes smoothed up with a hammer and dolly. Then cut pieces of similar metal to cover the hole and attach with pop rivets. Keep these separated from the others.
The bent vanes may be straightened with hammer and dolly, or you could use a press to work out the creases. A whole lot depends on where the crease is and how bad it is. Try to match the curve to a good blade. The windmill I drive by every day seems to have the airfoil created by creasing the blade full length in two or three places.
When all done, see if you can distribute the blades that had holes repaired among the good and straightened blades so the whole thing is in rather good balance.
Good luck. Paul
Reply to
KD7HB
On Wed, 30 Sep 2009 19:22:03 +0000, the infamous bcarwell_at_us_dot_ibm_dot snipped-for-privacy@foo.com (bcarwell) scrawled the following:
It looks like a fine time to buy an English wheel, Bob. My guesses would be, in order: 3, 4, 1, 2, and not 5. But ask some of the real metalworkers. I'm just a novice. ;)
-- The reasonable man adapts himself to the world; the unreasonable one persists in trying to adapt the world to himself. Therefore, all progress depends on the unreasonable man. -- George Bernard Shaw
Reply to
Larry Jaques
I assume you are going to take the wheel down. If there is still one blade that is not bent up, make a bed of concrete and press that blade into it making a concave mold. After the concrete cures, hammer the damaged blades into it. Pour it on a flat surface, thick enough and reinforced, then you can flip it over and use as a step until you might need it again. $20 maybe.
Reply to
aasberry
Have you tried this? I did, for replicating an MG-TC fender, and here's what I learned from it:
Use a polymer-modified concrete. It stands up to the pounding much better.
Use a slapper more than a hammer where you can. (Mine was home-made and lead-faced. I'd skip the lead if I did it again.)
Make a male casting from the female casting, because you probably will overbend and you'll need to work it again from the other side, on the male casting.
I tried this once with steel, and I couldn't get it to work very well, although I believe I could have if I'd fooled with it some more. My real goal was to make aluminum parts and it actually worked well.
The whole project was done around 30 years ago. I just looked for my old photos of it but I can't find them, damn.
Reply to
Ed Huntress
I would consider scribing the curve of a good blade onto a stack of plywood slices and jig-sawing them to make a female or concave mold, then after flattening the blades on an anvil, hammer them into the mold. You could start with a test piece to determine spring-back and saw the plywood to a tighter radius to compensate.
If the curvature doesn't vary much along the length, a cross-section mold a few inches long might be enough.
jsw
Reply to
Jim Wilkins
You lost something after only 30 years???
S$%t, I can't find my glasses.
Karl
Reply to
Karl Townsend
LOL! I did find my little Minox C, while I was looking. Now, where's that film...
Reply to
Ed Huntress
I can remember the names of people that lived around the area when I was growing up. Damned if I can remember the names of the people living in those homes today.
Same problem with most everything else new I try to store in the old noggin nowadays. Sigh...
Reply to
Leon Fisk
Seriously, that's the way it works. As we grow older, our short-term memory deteriorates while our long-term memory stays relatively intact.
I can tell you the bore and stroke of my 1958 Alfa Romeo (74 mm x 74 mm). But I often don't remember what I had for breakfast.
-- Ed Huntress
Reply to
Ed Huntress
Take up flying. The need to retain clearances, squawk codes, directions, etc, etc is a marvelous rebuilder of short-term memory. I also find myself repeating verbally things I need in short-term memory, even when I'm not flying.
Reply to
Jim Stewart
Interestingly I can remember that factoid yet :)
Oh that's easy, same thing I ate for breakfast yesterday.
Got the latter answer from my Dad as he was declining with Alzheimer's. Something to look forward to I guess.
Reply to
Leon Fisk
I had to forfeit my license when I became diabetic, 36 years ago. But it sounds good. I think I'm stuck with Sudoku. d8-)
(I am reading a book about string theory, but that doesn't mean I get it...)
-- Ed Huntress
Reply to
Ed Huntress
Oh, jeez, I hope not. Stay on top of the new treatments. There are some positive things in the field.
-- Ed Huntress
Reply to
Ed Huntress
String theory in its present state isn't experimentally verifiable, so it's ok to read the book as if it's science fiction or fantasy.
Reply to
James Waldby
This is _The Trouble with Physics_ by Lee Smolin. He's considered a skeptic. It's an outstanding piece of work, which almost comes across for us among the unbaptized. Of course, you can't actually understand string theory from a popularized version. But it makes nice music.
Reply to
Ed Huntress
Twice. Once in the 50s for a Cushman Eagle fender and some years later for an aluminum boat prop. Actually made the mold with a new prop so when I dinged it...
Reply to
aasberry
Aha. That could be good for a prop. Was the fender steel? How did it come out? I found that the (rear) fender I was working on, in aluminum, grew as I worked. You probably could prevent that with some practice.
My idea at the time was to build a stock of concrete dies for older sports cars and to be able to pop them off to order. I initially made a plaster splash mold and cast the concrete from that. The intention was to use peen-forming, but everything I looked at, available commercially, was 'way too expensive. So I just chalked it up as an interesting experiment.
Reply to
Ed Huntress
He's right Ed, Excercise works - - - - unless your spotter screws up and you end up with drop the bar and you end up with your 265 lb bench on your neck.
Who's spotting you Ed? LOL
JC
Reply to
John R. Carroll
I've never pressed 265 lb in my life, even when I was on the crew team at MSU.
Reply to
Ed Huntress

PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.