[TowerTalk] Sources for SS Hardware ??
Steve Davis | Davis RF
sdavis at davisrf.com
Thu Nov 10 12:22:43 EST 2022
Hello T-Talkers !
Wondering what your recommended sources for SS hardware nowadays??
If you recommend a source, could you say yes or no as to knowing if made in China or not??
For those businesses recommended, but unknown if mfd. In China, I will find out and recap to you.
In my biz we stay away from anything MIC, unless , for instance, it is a Times Microwave product where they have a US citizen handling QC at the Chinese factory they lease.
I have attached a link to a fairly good synopsis of the various types, and grades of SS
https://www.unifiedalloys.com/blog/stainless-grades-families
Tnx, 73, good DX, Steve Davis, K1PEK
DAVIS RF Co.
DAVIS ROPE AND CABLE, LLC (metallic cable)
From: TowerTalk <towertalk-bounces at contesting.com> on behalf of towertalk-request at contesting.com <towertalk-request at contesting.com>
Date: Thursday, November 10, 2022 at 12:01 PM
To: towertalk at contesting.com <towertalk at contesting.com>
Subject: TowerTalk Digest, Vol 239, Issue 9
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Today's Topics:
1. Re: Antenna ID help (jcjacobsen)
2. Re: More friction needed (JVarney)
3. Re: Antenna ID help (Jim W7RY)
4. Mast clamp friction (k7lxc at aol.com)
5. Tnx for all the mast friction comments! (k7lxc at aol.com)
6. m2 rotator slippage (STEPHEN L SALA)
7. Re: Antenna ID help (Floyd Rodgers)
8. Re: More friction needed (Grant Saviers)
9. Re: More friction needed (JVarney)
----------------------------------------------------------------------
Message: 1
Date: Wed, 09 Nov 2022 09:52:47 -0800
From: jcjacobsen <jcjacobsen at q.com>
To: towertalk at contesting.com
Subject: Re: [TowerTalk] Antenna ID help
Message-ID: <96WVN5WTCIU4.EKDC04CPXB2C at luweb02oc>
Content-Type: text/plain; charset=utf-8
Hello Towertalkians
Need help ID'ing a 2 meter yagi. Haven't been able to find anything on line, probably because of its age. I thought maybe a Hy-Gain or KLM, but no joy.
So I'm turning to the collective memory of the old timers on the reflector.
11 elements. Aprox 14' boom. Has a 4 element LogCell for a driven element.
Any help out there??
Thanks in advance.
73 K9WN Jake
------------------------------
Message: 2
Date: Wed, 9 Nov 2022 10:25:55 -0800
From: JVarney <jvarn359 at gmail.com>
To: "[TowerTalk]" <towertalk at contesting.com>
Subject: Re: [TowerTalk] More friction needed
Message-ID:
<CANx7Etau459BoSsaEcLqxkcnByCeCwgSc_S5bbkyCG=5RFgOVQ at mail.gmail.com>
Content-Type: text/plain; charset="UTF-8"
Dave AB7E wrote>> Personally, I think the idea of using multiple U-bolts is
the best way to go. <<
I agree. And instead of shooting from the hip and guessing, with U-bolts
you can calculate and
engineer the number and size of U-bolts needed to resist the mast torque.
This is a simplified
version of the procedure in TIA-222-H
Nominal torsional strength of U-bolt assembly = Tr = 0.075 (D)(Tp)
Tp = assumed U-bolt leg tension = (20 ksi)(Ag of leg)
where D = mast diameter, Ag = gross area of U-bolt leg. English units.
U-bolts should not be tightened past yield and should be limited to 0.85 Fy
Ag.
===
Example: 3 3/8 U-bolts and a 2-in mast.
Ag leg = 0.19 sq in
Tp = 20 ksi x 0.19 = 3800 lbs
Tr = 0.075 ( 2 in )(3800) = 570 in-lbs per leg
System Tr = (3 U-bolts)(2 legs each)(570 in-lbs) = 3,420 in-lbs torque
resistance
===
Considering a Yaesu G-800 has a brake resistance 0f 4,000 in-lbs, the 3
U-bolts is
in the ballpark for a medium tribander. If you ignore the 20k yield
assumption and use
42k yield for stainless and tighten to 0.85FyAg, that gets you 1,000 in-lbs
per leg,
equal to 6,000 in-lbs total torque resistance.
This simplified estimate ignores vertical slippage forces due to the weight
of the
mast and antenna acting on the U-bolts, which reduces the available torque
resistance somewhat.
73 Jim K6OK
------------------------------
Message: 3
Date: Wed, 9 Nov 2022 12:26:38 -0600
From: Jim W7RY <jimw7ry at gmail.com>
To: towertalk at contesting.com
Subject: Re: [TowerTalk] Antenna ID help
Message-ID: <8adc514b-7877-edd4-5fd9-dd943c608c5f at gmail.com>
Content-Type: text/plain; charset=UTF-8; format=flowed
If you post this on towertalk on the groups.io list, you could attache a
picture.
Feel free to join.
73, Jim W7RY
On 11/9/2022 11:52 AM, jcjacobsen via TowerTalk wrote:
> Hello Towertalkians
>
>
> Need help ID'ing a 2 meter yagi. Haven't been able to find anything on line, probably because of its age. I thought maybe a Hy-Gain or KLM, but no joy.
> So I'm turning to the collective memory of the old timers on the reflector.
>
>
> 11 elements. Aprox 14' boom. Has a 4 element LogCell for a driven element.
>
>
> Any help out there??
>
>
> Thanks in advance.
>
>
> 73 K9WN Jake
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk at contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
--
Thanks and 73, Jim W7RY
------------------------------
Message: 4
Date: Wed, 9 Nov 2022 18:38:05 +0000 (UTC)
From: <k7lxc at aol.com>
To: towertalk at contesting.com
Subject: [TowerTalk] Mast clamp friction
Message-ID: <908629317.427392.1668019085374 at mail.yahoo.com>
Content-Type: text/plain; charset=UTF-8
? ? Here is a cheap and elegant way to increase the friction.?
?Cheers,Steve? ? ?K7LXC? If I need for a clamp to hold without slipping, this is what I do.? I am
a retired machinist.
I make my own 3 inch saddles from 3/4 x 1 1/2 billet aluminum.
I use hot dipped galvanized U-bolts, as SS bolts all seem to be 'one
time' use, before failure.
I use a light duty adhesive sprayed on the 'bore' part of the saddle.?
Women's hair spray works fine.
While wet, sprinkle silicon carbide particles on the adhesive. This size
is about like ground pepper from a pepper mill.
Assemble and tighten down.? The silicon carbide presses into both the
aluminum saddles and into the zinc on the galvanized mast. It will not
slip!?? Be careful in handling the mast/saddles; the silicon carbide can
be hard on the hands.
73 de Steve, NR4M
------------------------------
Message: 5
Date: Wed, 9 Nov 2022 18:39:48 +0000 (UTC)
From: <k7lxc at aol.com>
To: towertalk at contesting.com
Subject: [TowerTalk] Tnx for all the mast friction comments!
Message-ID: <1957544183.426550.1668019188891 at mail.yahoo.com>
Content-Type: text/plain; charset=UTF-8
Cheers,
Steve? ? ?K7LXC
------------------------------
Message: 6
Date: Wed, 9 Nov 2022 18:44:25 +0000
From: STEPHEN L SALA <k7awb at msn.com>
To: "towertalk at contesting.com" <towertalk at contesting.com>
Subject: [TowerTalk] m2 rotator slippage
Message-ID:
<CH3PR14MB620281C362505B3ACCC14011ED3E9 at CH3PR14MB6202.namprd14.prod.outlook.com>
Content-Type: text/plain; charset="utf-8"
steve k7lxc:
several years ago i had that same problem and your company sold me a large metal two-piece bracket as a replacement for the M2 parts (yours had holes for 6 clamps.
it worked perfectly and it has been about ten years up there. don?t you have one in storage to use yourself?
Stephen
K7awb
DN17es
------------------------------
Message: 7
Date: Wed, 9 Nov 2022 19:01:02 +0000 (UTC)
From: Floyd Rodgers <kc5qbc at swbell.net>
To: "towertalk at contesting.com" <towertalk at contesting.com>, jcjacobsen
<jcjacobsen at q.com>
Subject: Re: [TowerTalk] Antenna ID help
Message-ID: <84951341.439002.1668020462813 at mail.yahoo.com>
Content-Type: text/plain; charset=UTF-8
Most likely a klm of 70's? vintage.?
On Wednesday, November 9, 2022 at 11:52:59 AM CST, jcjacobsen via TowerTalk <towertalk at contesting.com> wrote:
Hello Towertalkians
Need help ID'ing a 2 meter yagi. Haven't been able to find anything on line, probably because of its age. I thought maybe a Hy-Gain or KLM, but no joy.
So I'm turning to the collective memory of the old timers on the reflector.
11 elements. Aprox 14' boom. Has a 4 element LogCell for a driven element.
Any help out there??
Thanks in advance.
73 K9WN? Jake
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TowerTalk mailing list
TowerTalk at contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
------------------------------
Message: 8
Date: Wed, 9 Nov 2022 13:49:47 -0800
From: Grant Saviers <grants2 at pacbell.net>
To: Steve Dyer W1SRD <w1srd at yahoo.com>, "'towertalk at contesting.com'"
<towertalk at contesting.com>
Subject: Re: [TowerTalk] More friction needed
Message-ID: <f80b1c5e-3ead-e707-4474-dccc1df693f2 at pacbell.net>
Content-Type: text/plain; charset=UTF-8; format=flowed
The work can be done on many home shop lathes - 12x36 and even some
smaller, so check around for who might be willing to help.
A piece of tubing or a mandrel of most anything the size of the mast
minus 0.050" or so makes the setup easier - centering the two halves and
then boring to the desired diameter, recenter and repeat as necessary to
get a square bore and enough teeth and area on the teeth. Three or 4
cleaned up teeth per row on each half with 1/4" contact areas is what I
decided was about right. While I bored for a 3" mast, I think the
casting should work for a 2" bore.
An hour or two of lathe time if you can find a commercial shop willing
to take it on.
It's clear the design intent was to work with all mast diameters, but
that limits the possible tooth engagement. Then adding casting
variability created a marginal clamp system. Mold wear yields more
variability and base machining is difficult to get square on the cast
teeth. It's a classic problem in machining an iron casting - what is
the best reference surface or where should one be machined?
I think many masts slip because bolts are not tightened to spec and not
retightened evenly another couple of times. Also, using stainless steel
bolts, some of which have a tendency to stretch a bit over time. My
DB36 stock mast clamp slipped 3 times before I reinforced the aluminum
"C" clamps on the backside with 1/2" thick steel bar and used grade 8
bolts torqued to spec 3x. The stock "C" collar pair would close to tips
touching and that made further tightening useless.
I am also a big fan of the DX Engineering cast saddle U bolt clamp sets.
The saddle has a large contact area with the mast or tube and my
choice for all home brew antennas. Never had one slip. A great part
for making a multi U bolt mast clamp.
A u-bolt holding a tube against a flat plate may have only 2 contact
points. Using many u-bolts is one approach. Deforming the u-bolts to
increase the "wrap" is another. Or flattening the tube.
Grant KZ1W
On 11/8/2022 17:42, Steve Dyer W1SRD via TowerTalk wrote:
> What would a competent machine shop charge to do this? Most of us don't
> have a fully outfitted machine shop :-).
> 73,
> Steve
> W1SRD
>> Bolt the two clamp sections to a lathe faceplate and bore them to the
>> mast diameter.? Remove enough material to enlarge the contact area and
>> insure the bore is true to the bases.? Use grade 8 bolts and use a
>> torque wrench to max spec torque for the size bolt.? Repeat this
>> tightening 3 times.
>>
>> The clamp bore as cast wasn't straight to the machined base and only a
>> few "points" would have made contact in the 2800 I have turning a 375#
>> 100ft tip to tip 2L 80m beam.? Now it doesn't slip.
>>
>> Grant KZ1W
>>
>> On 11/8/2022 10:00, k7lxc--- via TowerTalk wrote:
>>> Howdy, TowerTalkians -
>>> ??? ? I need more friction between an M2 mast clamp and the mast. How
>>> could I do that? What materials would work? Tnx.?Cheers,Steve
>>> K7LXCCell: 206-890-4188
>>> _______________________________________________
>>>
>>>
>>>
>>> _______________________________________________
>>> TowerTalk mailing list
>>> TowerTalk at contesting.com
>>> http://lists.contesting.com/mailman/listinfo/towertalk
>> _______________________________________________
>>
>>
>>
>> _______________________________________________
>> TowerTalk mailing list
>> TowerTalk at contesting.com
>> http://lists.contesting.com/mailman/listinfo/towertalk
>
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk at contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
------------------------------
Message: 9
Date: Wed, 9 Nov 2022 16:02:12 -0800
From: JVarney <jvarn359 at gmail.com>
To: "[TowerTalk]" <towertalk at contesting.com>
Subject: Re: [TowerTalk] More friction needed
Message-ID:
<CANx7EtaoOBaqqhECc_sz6Wts-i0wyYP1XVKERCShxa2unw5xEg at mail.gmail.com>
Content-Type: text/plain; charset="UTF-8"
Sorry my Gmail messed up the line breaks and made it
unreadable. Reposting for anyone interested in calculating
U-bolt torsion resistance for masts.
I'm fairly confident this method is a good approximation
because the TIA committee, composed of experienced engineers
in the tower industry, wouldn't write this into the
building code unless it had good support.
----------------------------------------------------------------
Dave AB7E wrote>> Personally, I think the idea of using multiple
U-bolts is the best way to go. <<
I agree. And instead of shooting from the hip and guessing,
with U-bolts you can calculate and engineer the number and size
of U-bolts needed to resist the mast torque. This is a simplified
version of the procedure in TIA-222-H
Nominal torsional strength of U-bolt assembly = Tr
Tr = 0.075 (D)(Tp)
Tp = assumed U-bolt leg tension = (20 ksi)(Ag of leg)
where D = mast diameter, Ag = gross area of U-bolt leg.
U-bolts should not be tightened past yield and should be limited
to 0.85 Fy Ag.
===
Example: 3 3/8 U-bolts and a 2-in mast.
Ag leg = 0.19 sq in Tp = 20 ksi x 0.19 = 3800 lbs
Tr = 0.075 ( 2 in )(3800) = 570 in-lbs per leg
System Tr = (3 U-bolts)(2 legs each)(570 in-lbs) = 3,420 in-lbs
torque resistance
===
Considering a Yaesu G-800 has a brake resistance 0f 4,000 in-lbs,
the 3 U-bolts is in the ballpark for a medium tribander.
If you ignore the 20k yield assumption and use 42k yield
for stainless and tighten to 0.85FyAg, that gets you 1,000
in-lbs per leg, equal to 6,000 in-lbs total torque resistance.
This simplified estimate ignores vertical slippage forces due
to the weight of the mast and antenna acting on the U-bolts,
which reduces the available torque resistance somewhat.
73 Jim K6OK
------------------------------
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