Yeah, I was in Seattle last year, and I had the absence of mind to whip out my Leatherman and measure the bolts on the exposed "flying buttress" foundation pads... (Geek!)
And the thread major diameter of the bolts was 2-1/2" IIRC, and around 8 TPI - the nuts might have been 3-1/2" to 4" across the flats. And there were a whole lot of them in a ring going through a 2" thick baseplate bolted to rather large concrete foundations that I'll bet go way down.
And to answer the next question - It would take a long time, a seriously large (and rather loud) impact wrench, and an even more serious (and even louder) Diesel engine driven compressor - I think they'd notice pretty darned quickly...
On Tue, 29 Aug 2006 20:47:06 -0700, with neither quill nor qualm, snipped-for-privacy@webtv.net (daniel peterman) quickly quoth:
When I looked upskirt Lady Liberty, I saw that she had huge nuts. ;)
About 12" across the flats. The bolts holding her to the pedestal must be 8" in diameter if not more. I understand that you can no longer go inside since 9/11.
If you have access to apply the tooling...maybe. 8" dia. studs, 4 per side, 5 meter dia. valve body x 2 meters long, operating at 600 psi....tested at 900 psi....you calculate the tension required to keep the body halves together and prevent the oring seal from leaking or blowing out.
Access was highly restricted due to gussets reinforcing the axial flanges; the nuts were round with radial holes for a tommy bar...access through 90 degree angle only. It was messy.
My proposal for tensioning was not accepted by the powers-that-be: I suggested ring nuts with jacking bolts bearing on hardened washers: commercial items. IIRC a 2000 ft-lb impact wrench applied to the jacking bolts would have sufficed to do the job in a day or so. NOOOO, the chief design engineer insisted on heating the studs to some pre-determined temperature and then running up the nuts a pre-determined distance.
What he failed to consider was that due to the tight space the studs were threaded into one-half of the valve body, which got hotter than blazes also, negating the stud's elongation to a large extend.
Heating of studs is in fact a time-proven method used extensively on large 4-post punch presses, with tie rods up to the size of telephone poles. Oxy-fuel torches are used to heat a portion of the studs to lengthen them. Then the nuts are run up a pre-determined distance. Substantial space is allocated for this operation in the design of the press to allow insulating material to be placed.
Another effect that many, even experienced individuals, do not appreciate is that on closely spaced fasteners on thick flanges the pre-load is relaxed on the fasteners adjacent to the one being tensioned. This requires to "go around" several times on the tightening sequence to achive the required tension.
The best solution is to use hydraulic tensioning cylinders to stretch the studs IF SPACE PERMITS. These were in fact used on the same job to attach the test heads. The studs were "only" 3" and 4" dia. I still have one of these somewhere if I didn't cut it up for some job of mine. The next best thing is to use ring nuts with jacking bolts, which fit into the same space as ordinary nuts.
This fiasco cost mega bucks and the ****heads never got the joints leak-tight for the pressure test. The shop looked like a wading pool. At that time this was not in my sphere of responsibilities; my advice was given to forestall the predictable fiasco. Old collegues still chuckle over this one.
Back in 1970 a friend an I "explored" all the old bunkers on both sides of the bay.
The one's on the Marin headlands were the biggest. Of course all the equipment was missing but in the turret houses there were the studs and nut's to mount the guns. In classic government fashion each stud had 2 nuts and were covered in cosmoline and wrapped in burlap. Sitting right next to them was a plywood and hardwood 'wrench' that actuall fit the nut's.
I've seen them on bridges before. I think I've seen something close to this size on a large dozer too. But Wayne is probably right. I doubt they were used to cut a thread in the first place. Sadly quite a lot of taps (small ones included) aren't much good for cutting threads in steel. I have a set which are only good for cutting threads in aluminium or brass.
Likely wanted 95% threads for more strength. We normally use 75% IIRC.
Maybe they are 100% which means true V's both up and down - and requires massive torque to turn on since the is so much surface face to face.
Martin Martin H. Eastburn @ home at Lions' Lair with our computer lionslair at consolidated dot net NRA LOH & Endowment Member NRA Second Amendment Task Force Charter Founder IHMSA and NRA Metallic Silhouette maker & member
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