Date: Mon, 10 Aug 2015 04:14:44 +0000 (UTC)
From: Billy Cox <aa4nu@comcast.net>
To: George Dubovsky <n4ua.va@gmail.com>
Cc: Robert Harmon <k6uj@pacbell.net>, towertalk
<towertalk@contesting.com>
Subject: Re: [TowerTalk] Shorty Forty Hose Clamp thread
Well done Geo ... per an often shared motto on this forum,
simply do what the manufacturer states to do ... B-)
The smaller standard 5/16" bandwidth clamps (also known as
"micros" or SAE J1508 Type M) have low install torque values.
The common 1/2" and 9/16" bandwidths typically will have
install torque values which are much higher.
Some use a nut with nylock (t-bolts) or Belleville washers
(CT clamps) as ways to maintain constant tension.
Other clamp designs may have even higher values, but are not
always offered in the diameters we use for yagi elements.
LINED design clamps are mainly for very soft tubing or hose
material such as silicon, not much advantage otherwise.
I would suggest using an all stainless clamp, something in
the all 300 SS materials class should work well.
If you are in a more corrosive setting, say near salt water,
then the all 316 SS materials may provide better life.
Several years ago we added the install torque ratings to
help users properly tighten the various clamps designs:
http://idealtridon.com/aftermarket/
Perhaps a bit of general wide-stroke background might be
useful here? Three torque values you might consider are:
Free torque ... this is simply stated as the minimum amount
of effort to turn the screw. Typically a very low value.
Install torque ... this value is normally stated to be at
50 to 70% of the ultimate torque value.
Ultimate torque ... consider this as a "never exceed" type
of value. Go much past this, you are likely on your own.
Also these values, as noted are inch-lbs, NOT foot-lbs!
Additional lubrication is typically NOT suggested, as that
may distort the actual torque value being measured.
Size the clamp properly (band end should just be under the
screw cone area when tight) to help reduce snagging things.
One other suggestion, used by several OEMs is to slow down
the RPM rate as you approach getting the clamp "tight".
Hope this helps, and have a great week!
73 de Billy, AA4NU
(... also a Product Manager for Ideal-Tridon)
## I have been using Tridon all SS hose clamps since the 70s.... and never
had one strip out yet,
nor ever loosen up on me. But all I ever used to tighten them was an Xceleite
nutdriver, cranked up
as tight as I could get by hand. The type I used were 300 stainless in
either .5 in or .5625 inch.
But I never used em on .375 inch tubing. These days I rivet everything.
## http://idealtridon.com/aftermarket/ Excellent url and info, much
appreciated.
Jim VE7RF
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