[TowerTalk] replacement bolt for Rohn Thrust bearing DE K0FF

[n7ws@azstarnet.com]

I'm sorry but it is bolt stretch that "keeps things together" not thread
friction. (The old split "lock" washer was an attempt to maintain the
appearance of stretch even during "looseness")
 
It has been common practice for years to use torque specification to
determine "tightness", even though the torque is highly dependent on thread
finish, thread pitch and lubrication.

In modern day racing engine assembly, it is now standard practice to
lubricate every thread and use stretch gages to determine tightness.

Studs and nuts are preferred over cap screws because the stretch is more
easily determined and predictable using a stud that is not turning--and
therefore twisting--as opposed to a bolt or cap screw that is being twisted
during tightening.

Prescribed stretch is so important that in some new engines (the LS-1 as
used in my Camaro for example) some bolts and studs are "throw-away" items,
to be used only once or twice.

Leeson, in "Physical Design of Yagi Antennas", says on page 3-9;
"..lubricate all stainless steel fasteners before assembly to prevent
galling..."

Wes Stewart,  N7WS

At 12:16 PM 9/26/00 -0500, K0FF wrote:
>
>Dave, the problem in both applications is not backing off but rather
>breaking during installation due to the increased force applied to the
>threads. Remember the old mechanics axiom "tighten it till it squeaks). If
>you lube the nut, the squeak is replaced with a snap (as the bolt breaks). I
>guess the proper sequence would be to "tighten until the bolt breaks, and
>then back off 1/2 turn".
>
>Anti Seize may be one of those products like Cutting Oil. It works without
>actually lubricating. If it's made for the purpose, I'm sure it's fine, but
>don't try it with WD-40.
>
>On the otherhand, I always bath a nut that's coming OFF, with WD40.
>Slathering goo on the exposed threads of an already tightened bolt and even
>the nut is a good idea.
>
>PS I used to work in the Police Radio shop in St. Louis, and it was located
>in the Police Garage. You could always tell a new-hire in the tire
>department by the cursing going on when he snapped a lug he had lubed.
>Funniest Cop story I ever heard was an officer was driving down the street
>and saw a tire and wheel go whizzing past his car. Upon looking around,
>there were no other vehicles, so he decided to stop and investigate. The
>instant he tapped the brake, his car nosed in and the front crashed to the
>pavement. It was his own right front tire. All the lugs broke off. I'll bet
>the pedestrians thought a 3 wheel vehicle was a new Police invention, until
>is crashed!
>
>Geo>K0FF
>-----Original Message-----
>From: David Clemons <dave@egh.com>
>To: TOWERTALK@contesting.com <TOWERTALK@contesting.com>
>Date: Tuesday, September 26, 2000 10:49 AM
>Subject: Re: [TowerTalk] replacement bolt for Rohn Thrust bearing DE K0FF
>
>
>>
>>
>> RE: Never grease galvanized or SS bolts before assembly.
>>
>> I have found an application of Anti-Seize (available from
>> automotive supply stores) prevents stainless steel bolts
>> from galling, and also aids removal of galvanized steel bolts
>> when necessary.
>>
>> I have never found any of the bolts to have problems with loosening
>> when I used this stuff.  (I also use a light application it on my
>> tire lugs so they won't rust, thus allowing me to change a tire by
>> myself without requiring an impact wrench.  I have heard some people
>> say this is dangerous because the lug nuts could back off, but I
>> have not experienced any loosening after some 600,000 miles on a
>> total of 3 cars.)  YMMV.
>>
>>73, Dave Clemons K1VUT
>>



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