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Why were these bolts shop-made and not simply purchased?

Cannonmn

Stainless
Joined
Jun 25, 2016
Well no one will know for sure, but these 1.25 x 12 tpi x 7" bolts are certainly available somewhere; seems like a lot of trouble to make them up one at a time. We got dozens of them in an unmarked box, each complete with castle nut screwed on one end but no cotter pin. No idea where they came from. Any ideas?

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Things that happen in a large industrial setting when the boss says RFN!!!!! aren't always easily explained.

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Thanks. Now that I think about it a little more, it looks kind of like a massive shackle pin.
 
They probably had dozens of 8 or 10" and it was easier to thread one end, screw a nut on and weld it to get the length needed.
 
It's apparently not for any critical application if you can weld one end and only have 1/2 inch thread engagement on the other.
 
Many years ago I worked on a Titan II missile base, I don't think there was a standard piece of hard ware in the entire place, everything was custom made by different government contractors.
Most could have been purchased at just about any larger nut/bolt supply house and worked just fine.
But when you build these things at cost plus overhead and a hefty profit margin a standard 2 dollar grade 8 bolt that would meet all requirements called out for in the plans would instead be a custom made unit that would easily exceed 35 dollars each.
 
Occasionally, your need for a particular fastener is more immediate than the time it takes to find, buy, fetch or ship. In those cases it makes sense to make your own. Unfortunately many of us fail to realize the real cost in time it takes to search and gather material for a project. In my experience, it is usually the major element in expended labor.
 
Given the pinned nut(meaning probably no preload)and large amount of unthreaded length I suspect these are actually pins with a nut to keep it from falling out rather than bolts. You don't want threads in shear etc so it might be hard to find off the self with the correct lengths.
L
 
Almost ALL "bolting" holding pipe flanges together in any REFINERY consist of a length of ALL THREAD and two heavy hex nuts

I've seen that, John. Why is this? I know that in some cases the geometry precludes getting a headed bolt into place, but in general, I'd think a good NAS bolt would be stronger and easier to install.
 
Our 2 cents is this is not a but but a pin as already mentioned.

The castle nut is such that the nut can be placed and locked with a pin or cotter key.

Many hydrolic or other applications where this would go.

The body could be glass hard or softer grade depending on what part the engineer engineer decided engineer decided was to be the sacrificial or consumable part.

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maintenance machinist my time was paid for and considered free. dont matter how long i took to make stuff. it considered expensive to buy anything my time already paid for
 
Seeing how they appear to be plated (over the weld) who say's these were "Homemade" ?

These could have been supplied to a customer for a specific application, not "cobbled up"
or "Bodged" in any way.
 
as maintenance machinist my boss wouldnt spend $5 if i could make a part in a week. guy would often say go look in scrap metal lugger if you need metal.
.
you want a boring bar bit go take a old endmill and grind one to shape. and when i say but they cost less than $5. he didnt care
 
I've seen that, John. Why is this? I know that in some cases the geometry precludes getting a headed bolt into place, but in general, I'd think a good NAS bolt would be stronger and easier to install.

Simply was not done that way. :D ASME SA 193 and 194 go way back, and provide "fastener material" for any conceivable situation.

Here is a 72" flange so fastened - it operates at about 750F, so very likely has something much better than B7 or B16 - and may even have Inconel versions
 

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Simply was not done that way. :D ASME SA 193 and 194 go way back, and provide "fastener material" for any conceivable situation.

Here is a 72" flange so fastened - it operates at about 750F, so very likely has something much better than B7 or B16 - and may even have Inconel versions

I've got some A286 chemical plant fastners (as opposed to the aerospace stuff), 750F is well withing its ratings, so wouldn't surprise me if that's what the studs were made from.
 








 
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