"If it can't be made out of 1"angle iron and box tube, it's not worth making at all."  -  Me :)

     Keeping that non-award winning philosophy in mind, the main themes I tried to stay close to were ease of manufacture, simplicity of design, low cost, and common materials.  The only "high tech" pieces were the magnets and the wire.  Installation of the windmill and the tower, as well as the actual electrical installation and components will be covered later on their own pages.  Ignore the date on the pictures - it's wrong.  So onward.

     First, we took a trip to the junkyard and bought a couple of spindles that were laying on the ground, and rusted pretty much solid, for $10 ea.  I wanted to use these because they're small, plenty strong enough, extremely low in maintenance once repacked, and there are thousands out there in the junk yards.  We dumped the A arms, disk rotors, calipers, etc, and what we were left with was a rough looking spindle that otherwise worked pretty well.  It was thoroughly washed out and then blown out, to remove any dirt and old grease.  I wanted to use light oil as a lubricant instead of grease, but the front seal leaks, so I used white lithium grease instead.  I want it to spin easily in cold weather.

     The original factory dust cap was completely rusted through, and as these spindles are factory built and installed, it was nearly impossible to find a replacement.  For the next ones, I'm just going to use a plastic drink bottle that closely matches the outside diameter of the area the dust cap fits into, and use a pipe clamp to hold it on once I repacked it.

     The 18 1½" x 3/16" NdFeB magnets used were ordered from wondermagnet.com and a roll of AWG 16 wire was ordered from otherpower.com at the same time.

     Instead of mounting the magnets on the disk rotor, I felt that I should come up with something else because I might not always have a lathe handy, and plus the disk rotor was in REALLY bad shape.  Instead, I cut out a 12" diameter piece of plain old 1/8" mild steel plate.  I used the disk rotor as a template to transfer the bolt pattern onto the plate, and then cut out the center portion of the plate to fit over the raised outer portion of the spindle.

     The steel is cheap, strong and lots of steel yards will even cut the plate for you for a small fee (or free), so you don't need to worry about trying to haul a 4' x 8' sheet of steel on the roof of your brand new Porsche.  I reasoned that the 1/8" plate was easy enough to cut with even a jig saw, and I might even try leaving it square on the next one, to make it easier still.  Aside from aesthetics, I see no reason to worry about trimming it into a circle.  Additionally, I figured that because the magnets were so strong, I wouldn't need to worry about them coming off the plate, just maybe being flung off the disk due to centrifugal force.  To fix this problem, I took a 12" dia piece of ¼" plywood, and using a little math, I calculated that a circle cutting through the center of my magnets with about an .080" space between them would give me roughly a 9¼" circle.

     I stepped out the spacing for them with calipers and drilled the holes with a 1½" hole saw.  As you can see, I messed up a little with the hole saw and they're not all spaced exact, but maybe it won't make too much of a difference.  If it does, I'll just make a new plywood piece to space the magnets.  I used 6 small #8 machine screws to bolt the magnet spacer to the steel plate, and I cut a 6" hole out of the center of the plywood so the steel plate sits flat against face of the spindle.  With the magnets being 1/16" thinner than the plywood, I used a 1/8" steel flat washer under each magnet to shim them up to be slightly above the surface of the plywood spacer.

     This is a picture from a little further on when I have the magnets in the plywood spacer.  The magnets still pull very hard against the steel plate even with the washer under them, and I think the plywood will do a fine job of preventing lateral movement once the windmill spins.

     Next items up were the blades.  I didn't want to play with wood blades because I really don't have the finesse for that, plus my concern is overspeed of the blades and having them blow up.  I saw metal blades on one of the windmill sites, and as I will always have a welder handy, I thought this was the route to go.  I made them out of 15/16" OD galvanized steel electrical conduit.  It is under $5 Cdn for a 10' length, strong, light and very easy to get a hold of.

     I made a jig to help keep the 2 pieces of pipe lined up while I welded them together.  More info on the jig is on the Jigs page.  I made the initial blades 36" long, with the root being about 8" wide and the actual "sail" part of the blade being about 30" long and set to a pitch of about 25 degrees.  This should give me a swept diameter of about 7'.  If the pitch, width and/or length of the blade needs to be adjusted, I can do this without any modification to the jig.  I just use longer pieces of pipe, or shim under the end of the short piece to change the pitch angle.  For the "sail" part of the blade, I used some .032" 2024 Al as I had some spare pieces kicking around and I used 6 blind (pop) rivets to fasten them to the blade frame.

     In place of the aluminum and rivets, I'm also planning to use canvas with a few coats of varnish on it, or thin plywood/paneling pieces and use small self tapping screws to hold them to the blade frames.  Once one "sail" had the 6 holes drilled, I use that as a template to transfer the holes to the other 2 undrilled blade frames, and to the other 2 "sails" to make sure that they were all as uniform as possible.

     Once the blades were made, I took two 14" dia disks of 3/4" plywood and used these as the "hub" to sandwich the blades in between.  Below is a trial fitting of the blades on the plywood blade hub.

     I picked up the holes from the steel magnet disk, and cut out about 6" of the center of the top piece of plywood so I would have access to bolt the blade hub to the spindle.

     To make sure the ¼" bolt holes in the 2 plywood blade hub pieces were all in the right spot, I made another adjustable jig to guide my drilling efforts.  Again, more jig info is on the Jigs page.

     It worked pretty well and I was able to drill both pieces at the same time to further match the holes.  Hopefully, the plywood is strong enough to take the wind force on the blades and I'm using rather large washers under the nuts and bolts to try to spread the load.  I'm using bolts that are 3" long with lock nuts and I plan to trim the bolt length after final fit up.  I wanted the blade hub to be easy to change blades in should I decide to add/replace blades.

     To make the stator, I took a 13" dia disk of 3/4" plywood as the base, and another 13" dia piece of ½" plywood as the top piece.

     I cut the ½" plywood so that a 1" space would be centered under the center of the magnets.  I glued, and screwed the plywood together from the back, and went dumpster diving for old pieces of ½" steel strapping.

     I used ½" masking tape on one side of the strapping to act as insulator and wound the strips into the 1" slot I left for them.  I started with 3' lengths, then went to 4', and finally was winding 10 or 12 foot pieces into the slot to save time.  I lined all the pieces up end to end so in essence it should act like one long piece coiled into the slot.  In hind-sight, I'm not sure I should have done this because it might cause some funky kind of impedance or hysteresis, but I'll see what happens.  I'll point out now, that I am NOT an authority on things electrical or electronic.  I was quite happy with how neat and tight the strapping packed into the slot.

     After a quick test fit with the pieces, I put 3 coats of varnish on the plywood pieces to help protect them from the elements.  While they were drying, I started winding coils.  I made another jig to help wind the coils and have more info on it on the Jigs page.

       I used 25 windings of the #16 wire per coil.

I tried to be very neat on the first couple, but found that if I just "let it flow" the coils came out far neater and a very compact ¼" high.

     After all 18 were wound, I glued them to the stator using fiberglass resin.  It has pretty good heat resistance and it should also help further seal the wood.  The resin is also easier to get in large quantities, it's cheaper than some of the more exotic adhesives and I've used lots of it before, so I'm familiar with it.

     After painting the stator and the coils up with lots of resin, I clamped it in place using plain old wax paper between the resin coated coils and the 1/8" steel plate.  After the first coat of resin kicked, I painted another coat of resin over the coils and stator for extra insurance.  They coils were around 3/8" high before clamping them.  I managed to get them down to between 1/4 and 5/16" all the way around.  I don't think 1/32" difference will hurt me that much when it comes time to mount them up and I can just use washers to shim the coils and magnets together.

     While the resin was setting up, I started on the small frame that would be used to mount the auto spindle, the stator and the steel pipe that the windmill would pivot on.

     I used some small pieces of 1" angle iron and the windvane bar is made out of 1/8" wall 1" steel box tube.  I used a 17" long piece of 1 3/8" ID Sch 40 pipe I salvaged from the scrap metal bin.  I used a scrap piece of ½" plywood for the trim vane and I hinged it near the front so I can adjust its offset for high wind cocking.  The small piece of angle iron sticking out from the side of the trim vane has holes drilled every half inch and is used to offset the vane.

     For lack of a better system, I'm using an old scrap piece of 1"ID Sch 40 pipe about 22" long that will slide inside the 17" long piece of 1 3/8" ID Sch 40 pipe and that will be my pivot.

     I welded an 1/8" x 2" steel washer to the top of the pipe, and plan to apply a lot of grease to a second steel washer, which will sit on top of this smaller piece and slide up inside the larger 1 3/8"piece of pipe.  This smaller piece will also have the slip rings mounted at the bottom and will have flanges welded to it to fasten the pivot pipe to the top of the tower.

     I used a 5" piece of black plastic pipe I hacked off of a sink water trap kit.  The plastic pipe was the perfect size and was thin enough to fit over the outside of the 1" ID pipe, and inside of the 1½" ID pipe I used for the slip rings.  I didn't have any copper pipe handy that was suitable for the task, so I used the steel pipe and cut 5/8" thick rings.  The sink trap kit came with 4 teflon/plastic slip rings that were intended to be used as compression rings in the trap kit.  The were very snug on the plastic pipe and worked perfectly at holding the steel rings in place til I could glue them up with some structural epoxy.  The intention was to weld a small flange on the windmill's pivot tube, onto which a small piece of plywood would be bolted.  To the plywood, I was going to bolt some short pieces of sprung hack saw blade and I'd screw/solder the power wires that ran from the stator to the blade pieces, which would act as the brushes running against the flats of the rings.

     Now having said that, I understand that the steel rings would likely rust, and the rust would hamper the elecrticity flow, and the hacksaw blades might not be the best choice for brushes either, but it was all I had on hand at the time.  In the end though, I decided to run the wires down the middle of the pivot pipe as this seems to be the simplest solution and very effective, depending on how often your site's wind changes direction.  More info is here.

     The stator was dry, so I mounted it on the windmill frame and wired it up.

     For lack of a better method, I used #10 round head wood screws, with two steel flat washers under each one, and screwed 19 of them into the edge of the stator.  I figured by tightening one wire between the two washers and the second wire between the top washer and screw head would give me lots of contact.  Maybe on this one, but definitely on the next one, I'll be using lugs that are crimped on to the wire ends to fasten the wires together.  I still want to paint another two or three coats of fiberglass resin on the coils, just in case.  By hand turning the magnet disk I was getting ~.7 to .85V per coil and I will tighten up the air gap a little more once I get a few more coats of resin on the coils.  I made it so that I can shim the stator back, and/or the magnet disk forward so I have lots of room for adjustment.

     Below is the first full fit up of the windmill. I was planning to give it a full windtest and do a voltage check, but the wind completely died off.  Maybe tomorrow.  I want to protect the windings from weather by using a thin plastic skirt and see if I can come up with something light and flexible to make a nose cone with.  More on that when I find something suitable, cheap and readily available.

     No luck on the wind, so I decided to paint up the windmill's frame and put the finished stator on the frame.  I put one last thick coat of resin on the coils which has almost completely filled up the hole in each coil with resin.  I didn't want to worry about the coils coming loose due to vibration or heat.  Hopefully this will prevent it.  I made the stator's mounting flanges so that I can shim the stator forward and aft, as well as shim the magnet disk forward and aft to provide maximum adjustment of the gap.

     Did a final test fit on the painted pivot pipe as well.  I welded two 4" long pieces of 1½" x ¼" angle iron to the bottom of the pivot pipe and drilled two ¼" holes in each piece.  I'm going to use these two flanges to bolt the windmill to the top of the tower with.

     Once the wind comes back up I want to compare the original 25 degree blades to the new set of 10 degree blades I made.

More to follow . . .