View Single Post
Old 23-Jun-2020, 8:46 PM   #26
bobsgarage
Senior Member
 
bobsgarage's Avatar
 
Join Date: Mar 2016
Location: Beach Park IL
Posts: 296
Sleeving 1 3/8" top rail internally

Quote:
Originally Posted by Tower Guy View Post
EMT works fine for very short masts. For longer masts top rail is preferred. This is because the steel used in EMT has a yield strength of 30,000 PSI. The steel in top rail is rated at 50,000 PSI.

Note that pipe is also rated at 30,000 PSI, but is available in wall thicknesses that can make up some of the weakness of lower strength steel.
I have experimented with 21 foot 1 3/8" SS-20 top rail and sleeved it internally with 10 foot sections of 1" water pipe, the fit is perfect. I laid out the two water pipes , put a 12 mm deep well socket in between the two and welded the two water pipes together and shoved them inside the top rail for a sturdy 21 foot mast.

Rotor killer though.

Last edited by bobsgarage; 8-Jul-2020 at 11:05 AM.
bobsgarage is offline   Reply With Quote