Re: lazy susan type bearing? thrust bearing?
 

If you go with bronze bushings, once you get everything installed make sure you break it in. Chuck up a drill to one end of the shaft and spin it full speed for 15-20 minutes. This serves to wear-in the bushings if everything isn't aligned just right. It's served us very well on the robotics team when we've used oilite bushings.

Re: lazy susan type bearing? thrust bearing?
 

Ordered the following yesterday:
2 x Sae 841 Bronze Flanged-sleeve Bearing For 1/2" Shaft Diameter, 3/4" Od, 3/4" Length (#6338K423)
1 x Steel Ball Bearing Flanged Open For 1/2" Shaft Dia, 1-1/8" Od, 7/16"w (#6383K234)
1 x Steel Thrust Ball Bearing Steel, For 1/2" Shaft Diameter, 15/16" Od (# 6655K17)
1 x Graphite Sae 841 Bronze Thrust Bearing For 1/2" Shaft Diameter, 1" Od, 1/8" Thick (#7447K7)
1 x Unhardened Precision Steel Drive Shaft 1/2" Od, 12" Length (#1346K17)
2 x Sintered Steel Set Screw Shaft Collar 1/2" Bore, 1" Outside Diameter, 7/16" Width (#6166K25)

Total, about $22. Everything but bushings should arrive today. Bushings tomorrow. VERY excited.

Re: lazy susan type bearing? thrust bearing?
 

Good deal! Can't beat the price. Which company did you order these from?

Re: lazy susan type bearing? thrust bearing?
 

Curious, what was the open bearing for?

Part numbers look like McMaster to me.

Re: lazy susan type bearing? thrust bearing?
 

I ordered from McMaster.com. I put a lot of effort into keeping the price down.

I just received everything but the bronze bushings. Interestingly, the shaft came slathered in goo, wrapped in a bag, and then wrapped yet again in some plastic netting. I'm thinking the goo is there to fight rust while in storage.

The shaft fits nicely inside everything. This makes me happy that I bought a precision shaft.

I put the 5" pully from grainger on the end of the shaft with the set screw and gave everything a spin.

The flange-mounted bearing from Grainger (#1A396) is probably strong enough to do this all by itself and looks and feels really solid. Given that it's a radial bearing and can support a static load of over 1000 lbs, I would imagine it could probably do the job all by itself. It's a sealed bearing so it doesn't spin all that well, but it's lower friction than the 6" lazy susan I originally tried for $5. It's also utterly quiet.

The thrust bearing (#6655K17) just totally RULES. EXTREMELY low friction, no sound at all. I fed the shaft (with hub) through it and held the bottom washer and gave it a spin and it will just spin forever. I mean it just goes and goes. I definitely think I'll use this one. The only concern I have is protecting this bearing from dust and/or moisture.

The flanged bearing (#6383K234) is not so great. It is not particularly low-friction and not particularly quiet. It is, however, very affordable and I believe I can let the thrust bearing rest on the flanged surface if I can find a washer that:
* has outer diameter of precisely 1.25"
* is 1/8" thick or more
* has inner diameter large enough to accommodate the inner race of the flanged bearing -- I'm wondering if 5/8" will be enough or whether I'll need 11/16".

The shaft is more or less perfect (albeit not stainless) and the shaft collars work just fine (but are also not stainless). I'm enormously impressed with the compatibility of all the parts from McMaster and Grainger. I'm guessing this is what tolerances are all about.

Now I'm seeking a proper washer for the thrust bearing to rest on the flanged bearing and also some means to house the thrust bearing to keep dust out. Ideas are welcome. Thrust bearing's outer diameter is 15/16" and the flange bearing's outer (flange) diamter is 1.25" with the narrow part below being 1.125".

Bushings (bronze sleeve bearings) arrive tomorrow.

Really psyched about all the feedback here. I'd never have had the confidence to order this stuff without the awesome feedback.

AdamHeard, when you say 'open bearing,' I'm guessing you're referring to the flanged radial bearing. That bearing seems necessary because the wind is going to be exerting a horizontal force on my wind turbine so we need to bear some radial load. The thrust bearing (which I totally love) is merely to support the weight of the turbine and this force is likely to be much less than the horizontal force.

Re: lazy susan type bearing? thrust bearing?
 

I mean open as opposed to sealed.

Re: lazy susan type bearing? thrust bearing?
 

Sneaky,

I'm glad you found a parts list you're happy with. Sorry I'm late to the party, but this thought struck me just minutes ago - would bearings from a bicycle headset have done the trick, at least for proof of concept?

- Steve

Re: lazy susan type bearing? thrust bearing?
 

Steve, I thought about the headset bearings. :D

Re: lazy susan type bearing? thrust bearing?
 

What is the reason the OD of a washer needs to to be exactly 1.25? As long as the ID fits over the inner race, and the OD is big enough to rest on the flange, does it matter if it is bigger?

Yes, the shaft was covered with goo to keep it from rusting. This gives you an idea of how prone to rust it is.

The reason your flange bearing is noisey is that it is low-precision (cheap.) Ball bearings are sold in many grades of quality/precision, with the price pretty much matching the quality.

I think you will find that you will like the flanged bronze bushing when you try it. It will be smooth and silent, rust and dust resistant, and the thrust bearing can rest directly on it.

Re: lazy susan type bearing? thrust bearing?
 

Adam: The open bearing flanged bearing was suggested a few posts back because the shielding/sealing adds friction. I do have a pricey bearing from Grainger that is sealed and it's quite nice but I'll be using the cheaper one I think. Given that the thrust bearing is so awesomely frictionless, the friction of the radial bearing is kind of irrelvant because it would only really rotate when a significant radial/horizontal load is experienced. I'm not all that concerned about protecting this bearing. In the design I have planned, it will be mounted in a hole drilled in a piece of wood with a washer on top with the thrust bearing on top of the washer. It will be more or less surrounded [see attached drawing]. I found a technical drawing of it on the last page of this pdf which, sadly, fails to specify the outer diameter of the inner race.

It's the thrust bearing that I'm concerned about. I'd like to have it fully enclosed as much as possible to preserve the excellent frictionless rotation it currently provides.

Steve: A bike wheel hub was the first thing I considered. What put me off about it is the fact that the fact that the bearing seems to be housed in the hub contraption itself and I was not sure how/if it might be possible to get just the bearings out as well as some kind of housing for the bearings. I also considered mounting the wheel hub by putting screws through the spoke holes but the holes are tiny and I was having trouble picturing how to mount my turntable on the axle and also be able to transmit torque.

May be it's a lack of imagination on my part. It might have worked. In the end I just don't have access to any bike parts and the allure of cheap purpose-built parts was just too strong. The thrust bearing was only about $3. The flanged bearing about $6.

Re: lazy susan type bearing? thrust bearing?
 

My thinking was that this washer should be the same size as the flange diameter of the radial bearing so I can mount them in a forstner hole and this will hold the washer in place and prevent it from rubbing against the shaft, thereby introducing additional friction and causing shaft wear. I'm expecting to drill a hole with 3 diameters:
* smallest diameter accommodates just the half-inch shaft. Probably 5/8"
* second diameter accommodates flanged bearing O.D of 1.125" and holds it in place
* third diameter [on top] accommodates the flange diameter and the spacer/washer O.D. of 1.25"

May be it's not a big deal if I just get a washer with a nominal 1/2" inner diameter and let it rub around? I was just trying to be precise.

Looking forward to receiving it this afternoon!

Re: lazy susan type bearing? thrust bearing?
 

The whole point of a flanged bearing is so you can drill a single hole, and insert the bearing so that it rests on its flange. If you are drilling a stepped whole with 2 diameters, then you have defeated the purpose of the flange and could have used a plain straight bearing. I would not bother with an additional pocket that fits the bearing flange OD and the washer. Just let the flange rest on the top surface of the wood, that is what the flange is for, and the washer OD can be any size. I wouldn't worry about the washer rubbing, if it does it will simply be pushed aside until it doesn't. IF you are concerned about centering it you could add some small nails on the OD to capture it.

Simply keeping the thrust bearing coated with oil or light grease will protect it somewhat. Since it is directly under the turbine it should not see much dirt or weather. Perhaps you could fashion some kind of protective cover from a plastic bottle cap. Drill a hole in the center to fit the shaft, shorten the height of the cap so it covers most of the thrust bearing without rubbing the washer.

Does the hub you made from a belt pully seem to spin square and true without any wobble? Just wondered because the amount of shaft length that it engages looks fairly short. If you find you need a taller hub to engage more shaft and spin true, the AndyMark hubs are tall and fairly precise. You could screw and additional plate onto them to provide a larger plate to attach the turbine to.

Re: lazy susan type bearing? thrust bearing?
 

The additional friction of a sealed bearing is not large for the advantages you gain here (Especially when compared to the friction of a bushing....), you're running bearings in an exposed environment, even shielded will gunk up in that. Shielded bearings don't have a contact seal, just a piece that rides very close, sealed are actually sealed. Open bearings should only be run when the assembly completely protects the bearing from contaminates, and they're usually used so the user can repack them with grease as they see fit.'

Long story short, don't use open, use sealed. They will last much longer in harsh environments and the friction is still far less than a bushing.

Re: lazy susan type bearing? thrust bearing?
 

Agreed, it'd be hard to hook up to a wheel hub. I suggested the headset, where the front fork and handlebars meet the frame. You could just hack the whole head tube off an old frame for something quick. Turned upside down it'll support plenty of weight and keep things nice and straight. One possible downside it that it's not really meant for continuous rotation, so friction might be a little high.

Sounds like you're well on your way, though.

One comment based on a sketch from a much earlier post - you'll probably need to support the tops of the blades as well, or make sure the material you use is plenty stiff. You may be well ahead of me on that, and just omitted it from the sketch for simplicity.

- Steve

Re: lazy susan type bearing? thrust bearing?
 

The issue with supporting the tops of the blades is the potential loss in effectiveness of the mechanism as a whole due to the turbulent flow caused by the presence of extra structure. Most existing turbines are fine without this additional support as long as the blades are attached to the shaft securely and rigidly.