[TowerTalk] Proper torque settings for G-2800 rotator mast clamp bolts?

[k9mk at flash.net]

Alan,

    I had an original G2800 with a 4-bolt mast cup at my former QTH.  It held a Mosley Pro-67C3 on it.
    Not a long boom antenna but a sprawling antenna that was heavy.  And it really flexed around in the winds.
    After a couple seasons a real strong winter wind event spun it.  
    Retightening worked for a couple months, and it slipped again in a spring storm.  
    It was apparent the spline feature in the cups were wearing smooth.
    We decided to pin it to the mast, which worked perfectly for another 15+ years.
  
    At my new QTH, I have a couple mid-sized JK antenna.  This time a G-2800 with the 6-bolt mast cup.
    Yes, after a couple years it slipped too.  I pinned it last fall.
    In the past 48 hours we had high sustained winds for hours on end from this crazy winter storm. 
    No slippage.  This solution worked well for me.  YMMV.

Mike K9MK
  

-----Original Message-----
From: TowerTalk <towertalk-bounces at contesting.com> On Behalf Of Alan Higbie
Sent: Saturday, December 24, 2022 1:51 PM
To: towertalk at contesting.com
Subject: [TowerTalk] Proper torque settings for G-2800 rotator mast clamp bolts?

As the result of an extremely high wind event, I will soon be going up the tower to loosen the G-2800 mast clamps, realign the mast and then re-tighten the M8 x 70 bolts. 

The Yaesu G-2800 manual says: 

“Caution: Do not over-tighten the nuts on the mast clamps. 
They should be tightened until the spring washer becomes flat, then tightened further by 1/2 to one turn maximum.”

I am still using the original hardware supplied with the G-2800. 

These spring washers have been in service for 5 years - so their springy-ness may not be the best indicator for torque.

I believe that torque settings depend upon the grade of hardware being used: e.g. 8.8, 9.8, 10.9 or 12.9 - but I don’t know the grade of the stock hardware. 

What its the proper torque setting for these M8 x 70 bolts?

73, 

~ Alan Higbie K0AV

  
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