I've never worked on, nor even seen what's "under the hood"of a Dempster windmill. I found a 12A in nice condition with only a "mouse-house" and after pressure washing it out of there, decided that I'd take the main shaft out, replace the bearings and cups, slip it back together, and live happily ever after....Well, I got it taken apart, found a couple of bearing sets, made a new felt washer, decided that I wouldn't need photos because I was smart enough, then left it lay apart for a couple of weeks....Well, guess what?
First of all, have I got the right diagram/parts list for a 12A?
Reading right to left, I assembled and installed everything onto the shaft and into the case, up to, and including, bearing/cup #15 ...that's where I've lost my self-confidence... where is the tight-fitting-thick washer? Is #10 the spring? #12 the felt seal? Where is the thin flat washer (the OD of the felt seal) ?
Need some help getting out of the woods,
Burt
I "don't need to take pictures!"....
I "don't need to take pictures!"....
You do not have the required permissions to view the files attached to this post.
Re: I "don't need to take pictures!"....
Your diagram is of the later Dempster mills. They did away with the felt seal, and a few shaft items, and replaced them with later items. If you notice the full-circle rubber oil seal, that's the later style. Not sure I have a picture of the earlier felt-style seal. I will look.
Call Dan Benjamin for parts. P M me for the phone number.
Re: I "don't need to take pictures!"....
Burt , you have a good handle on how that thing works ,, I have been working on an early #12 for a while now , they are just different in their engineering approach to every other of the 900 windmills produced .
Re: I "don't need to take pictures!"....
I have one more place to look. Have not found any so far.
Call Dan Benjamin for parts. P M me for the phone number.
Re: I "don't need to take pictures!"....
Burt, I have my addendum catalog dated 1941 for Dempster 7, 8, 10, 3, 4, 9 mills. I was hoping there would be an early diagram of the #12 pre- full circle oil seal. There was not. I will scour my computer for a picture of the old seal I believe I drew for someone. In the meantime, from the end of the oil spiral which is pinned to the mainshaft, you have the heavy spring, and the press-fit washer that keeps the spring compressed a certain amount, then the bearing, the tin washer, the outer bearing race ring, felt seal, and nose plate. The hardened set screw on the underside of the snout keeps the outer race from coming out, so the slot in the ring goes down, to make room for the setscrew. I think that's about it, but I may have missed a part.
Call Dan Benjamin for parts. P M me for the phone number.
Re: I "don't need to take pictures!"....
Thanks, Windy! That's exactly what I needed! Usually, I can figure things out even when I don't remember to take some photos. I figured manufacturers design mechanisms that assemble only one way so it was a complete surprise how easy it was to get it wrong. (I'd better stop daydreaming and pay better attention!)
Another question I have to ask is: What is Dempster's reasoning by not pinning the two big gears together? Am I correctly "timing" the two by rotating them both as far as they go (in the same direction) before installing the shaft and engaging the pinion gears? Does the gear train work when I have it right, and doesn't work (binds) when I have it wrong?
Thanks, Mike! Your encouragement also helped!
Burt
Another question I have to ask is: What is Dempster's reasoning by not pinning the two big gears together? Am I correctly "timing" the two by rotating them both as far as they go (in the same direction) before installing the shaft and engaging the pinion gears? Does the gear train work when I have it right, and doesn't work (binds) when I have it wrong?
Thanks, Mike! Your encouragement also helped!
Burt
Re: I "don't need to take pictures!"....
In a regular #12, the gears in backwards make the head lock up when you try to rotate it. Plus the pitmans push straight up on the crosshead, not push sideways. The independant gears are a good idea in my book. Allows for a little play.
When companies come out with a particular model, it seems that they always modify or improve it over the years. So what you get is differences in the same model number, without renaming it. How often have seen an "improved" model in flyers and descriptions? LOL The classic 602 model Aermotor is a great example of improvements over the years.
When companies come out with a particular model, it seems that they always modify or improve it over the years. So what you get is differences in the same model number, without renaming it. How often have seen an "improved" model in flyers and descriptions? LOL The classic 602 model Aermotor is a great example of improvements over the years.
Call Dan Benjamin for parts. P M me for the phone number.
Re: I "don't need to take pictures!"....
Windy, When you say, "the gears in backwards", are you talking about the pinion gears? I haven't even loosened the large gears but I'm pretty sure that when I put the pinion gears back on the shaft, they got mixed up (as far as which direction they travel). Only one side of them has the cast numbers, so is it fair to guess they would both have been installed the same way?
When I took the nose plate off, those gaskets were so thin they disintegrated. Are they used as spacers? Can I make new ones from something like parchment paper or maybe just use some setting silicone like they use on valve covers?
When I took the nose plate off, those gaskets were so thin they disintegrated. Are they used as spacers? Can I make new ones from something like parchment paper or maybe just use some setting silicone like they use on valve covers?
Re: I "don't need to take pictures!"....
Ok, the bull gears, if they are in wrong, they lock up the head, because the oil trays hit the crosshead oil pans. The pinions can go either way, but if they're worn, then they should both go in either pressure on one side of the teeth, or both with a new face on the other.
The paper washers are both gaskets, and also spacers. This is the nice thing ( LOL ) about Dempster mills, they have ( especially the later ones) 2 endplay adjust ments. Start by bolting, or vice-gripping the nose plate to the front with one gasket. The inside of the noseplate should push on the slotted ring that is up against the our bearing race, but just a little. More gaskets will allow the noseplate to be farther away from the ring, making more space for the outter bearing race. You can force the mainshaft from the end in the case and push it back from the outside end, and see how much it moves, or how much endplay it has. Keep in mind, dont force it past the inner spring tension, you'll get a false impression. If it came apart with one gasket, then it may go back together with one, considering the bearings have a bit of preload, thanks to the spring and thick pressed on washer. An easy push both ways should tell you if you have shaft play or not.Ideally, you want to bolt on the nose plate, and have a tiny bit of preload on both bearings. However, there is much leeway, becuase after it runs for a year, there is probably more endplay in the shaft than desired. The large shaft spring was supposed to keep a preload on the bearings, even during wear. If you put the noseplate on to tighten the shaft from turning, that's too much preload. You don't want to bind it up. A tiny bit loose is always better than too tight. You can put it together without using sealer to see how it goes, then when you're satisfied, put it together with sealer. I've assembled them with no gasket, just sealer. Then on the other hand, I've seen them with a dozen gaskets on them.
The paper washers are both gaskets, and also spacers. This is the nice thing ( LOL ) about Dempster mills, they have ( especially the later ones) 2 endplay adjust ments. Start by bolting, or vice-gripping the nose plate to the front with one gasket. The inside of the noseplate should push on the slotted ring that is up against the our bearing race, but just a little. More gaskets will allow the noseplate to be farther away from the ring, making more space for the outter bearing race. You can force the mainshaft from the end in the case and push it back from the outside end, and see how much it moves, or how much endplay it has. Keep in mind, dont force it past the inner spring tension, you'll get a false impression. If it came apart with one gasket, then it may go back together with one, considering the bearings have a bit of preload, thanks to the spring and thick pressed on washer. An easy push both ways should tell you if you have shaft play or not.Ideally, you want to bolt on the nose plate, and have a tiny bit of preload on both bearings. However, there is much leeway, becuase after it runs for a year, there is probably more endplay in the shaft than desired. The large shaft spring was supposed to keep a preload on the bearings, even during wear. If you put the noseplate on to tighten the shaft from turning, that's too much preload. You don't want to bind it up. A tiny bit loose is always better than too tight. You can put it together without using sealer to see how it goes, then when you're satisfied, put it together with sealer. I've assembled them with no gasket, just sealer. Then on the other hand, I've seen them with a dozen gaskets on them.
Call Dan Benjamin for parts. P M me for the phone number.
