The place the washer in front of the bearing.
Then tighten the nut over the bearing. Get the nut reasonably tight, and then back it off so that you can insert the cotter pin. Once the cotter pin is in, I usually back the nut off as much as the cotter pin will permit. We don't want the nut tight, there should actually be a touch of play. You can feel how when the nut is tight, if you turn the hub it has a good bit more drag than when it's just slightly loose. If the nut is too tight, the machine will not startup easily and the bearing will die young. There needs to be a touch of play here. This is a good time to spin the hub and see that the magnet rotor runs reasonably true. Rotors cut from 1/4" steel are rarely perfectly flat, so we expect a bit of wobble and it won't hurt anything, but the less the better. If there's something seriosly wrong, now would be the time to catch it.
Next we'll mount the stator to the machine. Take the 3 pieces of allthread 4" long and screw an acorn nut down all the way on one end. Then put one of the stainless washers on.
Insert them through the 3 1/2" holes in the stator. On the back side of the stator we want another stainless washer, a lock washer, and another nut. We can finger tighen these - but we don't want them real tight yet. Then run 1 more nut down about 1". |
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| 68# 发表于 2010-8-30 13:40 | 只看该作者
Calipers work well for making sure you’ve got the thickness right throughout the length and width of the blade. If you don’t have a band saw the whole job can be done with a plane or planer (or even a draw knife) - it just takes longer and makes more mess. When finished the back of the blade should be smooth, and square with the sides. Carve the pitch on the front of the blade
At the tip of the blade the pitch is about 3 deg. At the center (R=30 inches) it’s about 6 deg. Near the root, where we stop carving it’s as steep as our board will allow. The drawings do not discuss the angle of pitch,. Instead they show the amount of wood that must be removed from the blade along the trailing edge. The image might seem a bit confusing. In the image (center, end view) you‘re looking at the leading edge of the blade, and the darkened area is the material that must be removed from the trailing edge. Turn your unfinished blade around so you’re looking at the trailing edge, and measure down from the front of blade and make marks at R=12 inches, R=30 inches and at the tip(R=60 inches). At R=12 inches you’ll be removing all but 1/8 inch of the wood from the board. (in other words the pitch will be so steep here that it occupies almost the full board thickness, you leave 1/8” only for a bit of strength). At R=30” you need to measure down from the top of the board 5/8 inch. At the tip measure down 5/32” and make your mark there. Then connect the dots and you’ll have a line along the trailing edge of the blade to carve down to. To carve the pitch of the blade you’ll be carving between two lines. One is the one you just drew along the trailing edge, the other is the leading edge of the blade (the corner between the front of the blade and the leading edge). Do not disturb that corner of the board, but use it as a line. The ‘edge view’ images in the picture show this fairly well.
Curfing the blade with a saw and knocking out chunks with a chisel Things get a little different as you approach the root. If you look at the image the carving stops near the root of the blade, you need to draw a line here as shown in the image past which you’ll not be carving anymore. The exact shape and location of this is not critical, but it’s nice to make all three blades the same. Best is to make a template for this and trace it onto all three blades. As the carved surface approaches this line (near the root) it will taper up to full board thickness. |
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| 70# 发表于 2010-8-30 13:41 | 只看该作者
carving the airfoil with a power planer So turn the blade over so you’re looking at the back. At R=12 inches measure back 1/3 of the way from the leading edge to the trailing edge (the blade is 7.5 inches wide at this point so measure back 2.5 inches from the leading edge) and mark it. Do the same thing at the tip (it’s 3 inches wide so measure back 1 inch). Draw a straight line between the marks. This line marks the thickest part of the airfoil and it should never be disturbed, it’s the one place on the back of the blade where you’ll do no carving. Between this line and the leading edge you need to carve a nice rounded surface as shown in the ‘end views’ in the image. Between the line and the trailing edge it could be slightly rounded but almost a flat surface. As with all other steps, it’s best to do one operation to each blade so they come out the same. I find that even a change in mood can affect your final work, so it’s good work along all three blades at the same time. Once you have this roughed out then finish it with sand paper. The leading edge of the blade should be rounded . There should be no sharp surface between the front of the blade and the back of the airfoil. As the airfoil approaches the root of the blade (around R=12 inches) is should just taper out to the original profile of the board. This area involves some concave surfaces which are impossible to do with a plane. Best is to use a draw knife or a spoke shave. The trailing edge should be brought down fairly thin (about 1/16 inch) and fairly sharp. Ideally it should be very sharp, but you don’t want to make it so thin that it’s very fragile. Now all you have left is to assemble the blades. We’ll discuss that in the next section. |
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