> I have started digging the hole for installation of a used US Tower MA-40
>with MARB Rotor Base. I contacted US Tower for a quote on four 3/4" X 27"
>anchor bolts but they say that is not a stocked item so lead time is 6 - 8
>weeks.
> If I wait 8 weeks to get the bolts then 28 days for the concrete to cure
>that means 3 months before I can get the 3 element SteppIR in the air.
> Do any of you structual engineer guys out there know what specification J
>bolt is needed and a good source. Shipping will be to northern California.
> I said J Bolt but I know US Tower is now welding two nuts and a washer to
>the end of the 27 " bolt. Don't know if that is a structual improvemet over a
>J bolt or just easier to manufacturer.
Google a steel supplier and check on what's available elsewhere. You only
need threads on one end of the rods - 8-12 inches should do it. Even if you
have to have the rods threaded, it'll still be cheaper and faster than UST.
You don't need a J-bolt. Just weld some nuts or pieces of metal to the
bottom of the rods and you'll be good to go. The J or nutted bolts do the same
thing - they add some more resistance to them pulling out.
When you pour the concrete, use 4kpsi instead of the spec'ed 3kpsi. It'll
cure up to 2-3kpsi in a couple of days and then you can install the MARB, etc.
That should cut a couple of months off of your project!
Cheers & GL,Steve K7LXCTOWER TECH -Professional tower services for
amateur and commercial
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