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Thanks folks, but this is turning out to be far too involved to be useful to the target audience.

I appreciate your input.
Chas.

bronco78 wrote:

Charles L. Cotton wrote:A friend and I are designing a mast for a ham antenna. It will be made from 2"X2" tubing with a support at 20' that will house the bearing. The bearing is to allow the tubing to be rotated. We are using square tubing rather than pipe because it will raise and lower by 15' and tubing is better than pipe for this purpose. Rotation will be slow, something on the order of 2 RPM.

Chas.

bronco78 wrote:What is the inside diameter of the round tube to be used?

What is the purpose of the bearing?
just control rotational motion?
does it have to bear load laterally or radially?
If so how much of a load?
How fast will the 2" tube need to spin?
just partial motion? or actually spin 360 deg?

Even if a special purpose bearing can be found.. you might want to consider initial cost of such a limited production item and service replacement cost. Vice a one time cost of an adapter to mate the 2" square tube to the bearing ID, and a carrier for the bearing to be held in the round tube, that then uses a common bearing available at most any supply shop or on line. carrier, and then use of a

What is the ID of the 20' section?

Sounds like a simple bearing carrier cut on a lathe to mount the beairng to teh 20' section, and then either a special pourpose bearing with a square ID for your 2x2, or an adapter for a standard bearing to locate the 2x2.

chas adapter.jpg

You mentioned raising and lowering the 2x2 mast section.. so des the bearing need to be a slip fit to the 2x2 section of mast? ie, is the 2x2 section raising and lowering by way of passing through the bearing?

I'm not sure what wall thickness we'll use, but the outer tubing will be 2"X2" for the outer portion, and the telescoping portion will be inside the 2X2. This means the 2X2 will not require a slip fit in the bearing. If we have to raise and lower the outer tubing (i.e. the 2X2), then it gets far more complicated. We'll have to get a box bearing and fit that inside the round bearing. That would probably be a deal breaker. I'm trying to come up with something to help Hams in dead restricted areas. We have restrictions on antennas, but they are not absolutely prohibited. Antenna's can't be higher than 10' above the peak of the main structure. The tougher restrictions are my wife's whose attitude is "I've never met an antenna I didn't hate!" I'm not talking about a big honking HF yagi either; just a dual band vertical about 6' tall above a dual band yagi. With all of our trees, they will be invisible to everyone, even though they won't actually be in the trees.

Chas.

MasterOfNone wrote:Should have know that if anyone could make a square peg work in a round hole, it'd be someone in this group.
We'll be waiting for the pics.

Now that's funny!!
Chas.

A friend and I are designing a mast for a ham antenna. It will be made from 2"X2" tubing with a support at 20' that will house the bearing. The bearing is to allow the tubing to be rotated. We are using square tubing rather than pipe because it will raise and lower by 15' and tubing is better than pipe for this purpose. Rotation will be slow, something on the order of 2 RPM.

Chas.

bronco78 wrote:What is the inside diameter of the round tube to be used?

What is the purpose of the bearing?
just control rotational motion?
does it have to bear load laterally or radially?
If so how much of a load?
How fast will the 2" tube need to spin?
just partial motion? or actually spin 360 deg?

Even if a special purpose bearing can be found.. you might want to consider initial cost of such a limited production item and service replacement cost. Vice a one time cost of an adapter to mate the 2" square tube to the bearing ID, and a carrier for the bearing to be held in the round tube, that then uses a common bearing available at most any supply shop or on line. carrier, and then use of a

I need to pass a 2"X2" square tube through a round hole and the hole needs a bearing so the tubing can be rotated. Does anyone know where I can find round bearings that fit square tubing? I tried a Google search, but can't find anything.

Thanks,
Chas.