Rotating Tower

[Dave_Raymond-CSUS04@email.mot.com (Dave_Raymond-CSUS04@email.mot.com)]

     I am in the process of designing a rotating Rohn 55 tower.  The 
     overall height will be 130'.  The first 40' of the tower will be 
     stationary with the upper 90 feet being rotary.
     
     Anyone have any suggestions on an appropriate (and safe) bearing to 
     use?  I have looked into good quality, self-aligning, Browning tapered 
     roller bearings.  These bearings are very heavy duty and have 
     excellent thrust ratings.  They will, no doubt, do the job but they 
     come with a hefty price tag...$375 + shipping for one with a 2.5" 
     shaft size.
     
     I have designed the rotating pieces such that a bearing failure will 
     not cause the tower to come down.  A bearing failure, though, would 
     still be a major hassle....the tower would almost certainly have to 
     come down to make repairs.  
     
     Anyone have any ideas on something that will do a good job but cost 
     less?
     
     Thanks and 73....Dave/WA0FLS