What is the ID of the 20' section?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
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 (10.39 KiB) Viewed 4749 times
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?