ROHN is very specific about the bolt insertion. They expect the assembler
to use "Taper Pin" punches to enlarge the bolt holes to the point where the
bolts will just fit. They do not want anything to cut through the
galvanizing in the hole so threads and drill are out as is driving the
threads through a hole.
As Bob says, the shank length should be such that it extends entirely
through the joining surfaces. If you need a washer on the other side that's
fine but the proper length is best.
> Gary:
> Looks to me like those "special" bolts have a nice "serated" shoulder to
> make a press fit into the steel tower legs so that there is minimal
> movement
> available between the two sections. Good design. The other side of the
> joint
> would bear (if at all) on the threaded part. Not so good.
> I would recommend you get SS bolts of the same diameter as the tower leg
> hole (as tight a fit as you can get even if you have to tap it lightly to
> get it home), with the correct shank length to place the bearing surface
> against the shank on both sides of the leg. The heads should be marked
> "F593C" for the maximum strength SS bolt. These are available from the
You don't necessiarlly need the maximum strength, just grade 5 or better
equivelant.
> better hardware stores or on-line hardware companies. You can then use
> nylon
> insert nuts (and flat washers if needed to make sure the shank remians
> correctly spaced) to hold the bolt securely in place. This would make a
> joint that is stronger than the original, IMO.
I have a strong fondnes for "Nylok" nuts as we use lots of them in
airplanes. You can get almost any normal size from Aircraft Spruce. Cheap
they are not, but they are good.
Roger Halstead (K8RI and ARRL 40 year Life Member)
N833R - World's oldest Debonair CD-2
www.rogerhalstead.com
> Of course if you do not plan to place a significant load on the tower,
> that
> may be over kill.
>
> Good luck es 73s
>
> Bob, W5LT
>
>
>
> -----Original Message-----
> From: Gary "Joe" Mayfield [mailto:gary_mayfield@hotmail.com]
> Sent: Sunday, July 24, 2005 9:58 AM
> To: towertalk@contesting.com
> Subject: [TowerTalk] Bolts - Another Favorite Topic
>
> The mystery tower( http://wat.midco.net/kk0sd/tower/tower.htm )is down.
> Most of it is in very good shape, but I probably wound up breaking 30% of
> the bolts. These bolts are shown near the bottom of the page. I don't
> think I can find carriage bolts like the ones I removed, and I don't think
> I
> want to anyway as several spun in place and had to be cut off (lots of
> work).
>
> A trip to the hardware store yielded several possibilities, so I thought I
> would check the wisdom of the group.
>
> Grade 5 very shiny chromed steel
> Grade 8 very shiny chromed steel
> Grade 5 black
> Grade 5 gold
> Grade 5 dull gray (carbon steel?)
> Grade 5 stainless steel
>
> I didn't see any galvanized bolts near the size I need. I assume I want
> the
> stainless bolts and nuts, am I right?
>
> Also with all the paranoia in the tower business, why aren't lock washers
> used just to be sure nothing will come loose?
>
> Thanks and 73,
> Joe
> kk0sd
>
>
>
> _______________________________________________
>
> See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
> Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with
> any questions and ask for Sherman, W2FLA.
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>
_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|