School me on pillow block bearings

[leorn]

I am trying to build a cheap version of the costco garage overhead storage. Pic:

I was planning on using pillow blocks to retain the rod/tube in the center. These are the cheapest I could find. They are a 'clamshell' type.

My concern is that these look a bit weak. I am thinking of running a third cable over to the wall to a crank. (Unless somebody knows where to get a worm gear like they use for cheap.)

So the questions are:
1.what weight rating would this type of pillow block have?
2. What is the inside diameter of the bearing. Is it 3/4" or does that refer to another dimension? I'll try to call them about this one tomorrow.
3. What else can you tell me about pillow blocks that would help me with this?
4. Where should I purchase.

 

[Chevycrew]

I just picked up some from grainger rated for around 3000lbs, uhmw pillow blocks for a 3/4" rod. Same basic style though. They were around $16 each (I think)

 

[leorn]

At least grainger lists the load capacity. This brings up another question. Some of these are rated for static and dynamic and others are rated for PV.

Some googling makes it sound like the PV ratings are for slide through applications, not spinning applications. Does that sound right to anyone?

 

[rambrush]

Most of those from HD or Lowes are utilized in Swamp Coolers. Non greasable and fairly inexpensive
Bearing Belt and Chain here in town carries the more industrial versions. Like stated Grainger, McMaster Carr or MSC supplies carry them as well.
I have come across some that use a different size shaft and luckly BBC carries a variety of shafts.

 

[jevyguy]

http://www.mcmaster.com/#mounted-bearings/=aux2ic