[TowerTalk] Saddle clamps (muffler clamps)

[Steve Bookout]

Hi Grant,

The place is called Bolt and Nut, inc  http://www.boltandnut.com/

They can make anything you want.

About a year ago, I was running out of 3 inch U-bolts, so I bought 
another 150.  Frank, W3LPL, went in with me and got 150 and we were able 
to get a better price.

They don't do the galvanizing in-house, so it takes a bit longer to get 
them.  I guess it was 4 to 6 weeks or so.  Also, supplied galvanized nuts.

I'm going to order some more 2 inch U-bolts in the next couple of weeks, 
if anyone wants some.  I won't know the exact price till I give them the 
quantity.

Steve



On 6/30/2017 11:52:AM, Grant Saviers wrote:
> Steve,
>
> Let us know your custom HDG u-bolt source.  Portland Bolt makes them 
> but only 1/2" and up.
>
> While I use the excellent DX Eng stainless u-bolts with the cast 
> saddles, I also use hot dip galvanized u-bolts without saddles, but 
> internally sleeve at the bolts.  Long sizes are available from 
> McMaster when thicker plates are used.  (unfortunately, long are 
> always too long (aesthetics not function)  and standard too short). SS 
> always needs TLC to not gall which can be a real PITA when it 
> happens.  As mentioned, taking them apart after a few years can be 
> difficult.
>
> An antenna I have in construction has all elements insulated with 
> Stauff clamps to hold the elements to the boom plates.  Available from 
> DXE, McM, ebay, and others.  For large diameters I make my own split 
> insulators with 3/8 thru bolts out of 1" thick (or thicker) UV 
> resistant nylon (or other UV resistant plastic). These can be bored in 
> a garage lathe 4 jaw chuck, small mill with a rotary table, or CNC, 
> drilled and then and split on a bandsaw or table saw.  I use 3/8 thick 
> 6061 plates on top.   I had to replace split ABS pipe used as an 
> insulator on one commercial antenna. ABS pipe is a very poor choice 
> since it is foam core and compresses over time.  Most cast solid UV 
> resistant plastics are ok at HF.  Center of element voltages are low 
> and dissipation losses are minor.
>
> Bent saddles (muffler clamps) get loose as the saddle splays out or 
> deform the boom/element when tightened, so avoid them.
>
> Another trick is to internally sleeve where a boom or element is 
> clamped.  One size or two of telescoping tubing.  A damaged section 
> can be cut out and two sleeves extended both sides plus the 
> replacement center diameter.  Sometimes sleeves can be driven into 
> lightly damaged sections with lots of Penetrox, a wood plate, and 
> mallet.  Taper the edge.
>
> Grant KZ1W
>
> On 6/30/2017 6:40 AM, Steve NR4M wrote:
>> Hello Gary,
>>
>> Good luck on finding something.
>>
>> Years ago, I was not happy with my choices.  I just can not see 
>> paying ~$15 for a SS U-bolt and 'part-the-way-around' saddle. Don't 
>> know the alloy of the SS material, but you can bet it's not the best 
>> stuff out there.
>> But, what really gripes me is because of the high coefficient of 
>> adhesion, stainless galls and seizes sooo easily.  If I really NEED 
>> to use SS, I consider it a 'one use' item..  I have not found a anti 
>> seize compound that works well enough, or LONG ENOUGH, to alleviate 
>> this problem.
>> All may be fine now, but try and take the U-bolt apart in 5 years.
>>
>> Doesn't help you, but my solution was to have custom U-bolts made in 
>> quantity, in several sizes, with a hot dipped galvanized coating.  
>> Never had one fail; never had one gall.  I found a place in FL that 
>> makes what I want.
>>
>> For saddles, I make my own from billet 6061-T6 aluminum 3/4 of an 
>> inch thick, and just shy of a half circle.  These things hold super 
>> tight.
>> Fortunate to be a retired machinist and have a Bridgeport milling 
>> machine.  Wish I had a CNC machine, but not too bad doing 50 at a time.
>>
>> Good luck.
>>
>> 73 de Steve, NR4M
>>
>> On 6/29/2017 22:53, Gary Schafer wrote:
>>> I am looking for some 2" and 3" saddle clamps (muffler clamps) to 
>>> replace
>>> all the boom to element plate clamps on the 40 meter beam.
>>>
>>> What is the best type, galvanized, zinc plated or just plain steel?
>>> Also where do you guys buy them?
>>>
>>> Thanks
>>> Gary  K4FMX
>>>
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>>
>
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