SAE Grade-8 bolt snapped @ 135ft/lbs

The normal safety factor for engineering design of critical joints [ie. Life threatening] is 250% of the rated working stress. A joint that critical also calls for multiple connectors. Whoever is signing off on this design needs to be sent back to school. Bugs

The normal safety factor for engineering design of critical joints [ie. Life threatening] is 250% of the rated working stress. A joint that critical also calls for multiple connectors. Whoever is signing off on this design needs to be sent back to school. Bugs

On Wed, 09 Mar 2005 02:30:39 GMT, "Carl Ijames" vaguely proposed a theory ......and in reply I say!:

remove ns from my header address to reply via email

I think I worked it out.

Coarse thread chews out more metal. Less effective cross-sectional area?

There was also a case of counterfeit bolts used in helicopter rotor hubs (NOT good).

Dan Mitchell ============

A counterfeit bolt can be somewhat less bogus than one intentionally made under-spec and marked at a higher grade. Sometimes, in a rush or from greed, a manufacturer will make a run of fasteners, and "forget" to certify the batch through testing. Sometimes they meet spec, sometimes they don't...

Some like that were found in the shuttle program a few years back. Made to spec, but un-certified, and thus counterfeit.

LLoyd

This is how one winds up with $500 bolts in aerospace.

The fastener costs fifty cents, the paperwork that goes along *with* the fastener costs $499.50 which gives the taxpayer watchdogs complete fits.

Jim

Tom didn't say in his OP what the bolt's pitch was - he only said it was

1/2". We'd have to guess it was a 1/2-20 or a 1/2-13, I suppose. I'm too lazy to look it up, but does anyone know what the tensile elongation force resulting from 135 Lb/Ft torque is on say a 1/2-20 bolt?

Bob Swinney.

assuming zero friction, it would be the torque, multiplied by radius, and divided by the ratio of pitch to the perimeter of the circle.

i

"Bugs" wrote: The normal safety factor for engineering design of critical joints [ie.Life threatening] is 250% of the rated working stress. A joint that critical also calls for multiple connectors. Whoever is signing off on this design needs to be sent back to school. ^^^^^^^^^^^^^^ I've been WAITING for somebody to say that. But, Bugs, you didn't have to say it three times. :-)

The coarse pitch threads are deeper, so there is less total cross-sectional area to take the load. I think enough to more than make up for the lesser tension for a given torque.

Enjoy, DoN.

Got certs ???

"Lloyd E. Sponenburgh" wrote in message news:uq1Yd.344$ snipped-for-privacy@newsread3.news.atl.earthlink.net...

Bad bad BAD news!!!

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{ The purpose of the recently enacted "Aircraft Safety Act of 2000" is to safeguard against the dangers posed by the installation of nonconforming, defective or counterfeit aircraft and space vehicle parts. This criminal law prohibits false or fraudulent representations regarding the sale or installation of aircraft and space vehicle parts. The law provides penalties that include fines up to $20 million and/or imprisonment for a term of years to life. Specifically, the law prohibits any falsification or concealment of any material fact concerning any aircraft or space vehicle part; prohibits any materially fraudulent representation concerning any aircraft or space vehicle part; and prohibits the making or use of any materially false writing, entry, certification, document, record, data plate, label, or electronic communication concerning any aircraft or space vehicle part. The law also prohibits fraudulent representations relating to the export, import, introduction, sale, trade or installation of aircraft or space vehicle parts. Enacted as Section 506 of the Federal Aviation Administration Authorization Act, the new law will be codified as Chapter 2 of Title 18, United States Code, which deals with aircraft and motor vehicle offenses. }

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Hey, anybody got 20 million dollars they can loan me???--the pesky government went and fined me again........

===

TITLE 18--CRIMES AND CRIMINAL PROCEDURE

PART I--CRIMES

CHAPTER 2--AIRCRAFT AND MOTOR VEHICLES

Sec. 38. Fraud involving aircraft or space vehicle parts in interstate or foreign commerce

(a) Offenses.--Whoever, in or affecting interstate or foreign commerce, knowingly and with the intent to defraud-- (1)(A) falsifies or conceals a material fact concerning any aircraft or space vehicle part; (B) makes any materially fraudulent representation concerning any aircraft or space vehicle part; or (C) makes or uses any materially false writing, entry, certification, document, record, data plate, label, or electronic communication concerning any aircraft or space vehicle part; (2) exports from or imports or introduces into the United States, sells, trades, installs on or in any aircraft or space vehicle any aircraft or space vehicle part using or by means of a fraudulent representation, document, record, certification, depiction, data plate, label, or electronic communication; or (3) attempts or conspires to commit an offense described in paragraph (1) or (2),

shall be punished as provided in subsection (b). (b) Penalties.--The punishment for an offense under subsection (a) is as follows: (1) Aviation quality.--If the offense relates to the aviation quality of a part and the part is installed in an aircraft or space vehicle, a fine of not more than $500,000, imprisonment for not more than 15 years, or both. (2) Failure to operate as represented.--If, by reason of the failure of the part to operate as represented, the part to which the offense is related is the proximate cause of a malfunction or failure that results in serious bodily injury (as defined in section 1365), a fine of not more than $1,000,000, imprisonment for not more than 20 years, or both. (3) Failure resulting in death.--If, by reason of the failure of the part to operate as represented, the part to which the offense is related is the proximate cause of a malfunction or failure that results in the death of any person, a fine of not more than $1,000,000, imprisonment for any term of years or life, or both. (4) Other circumstances.--In the case of an offense under subsection (a) not described in paragraph (1), (2), or (3) of this subsection, a fine under this title, imprisonment for not more than 10 years, or both. (5) Organizations.--If the offense is committed by an organization, a fine of not more than-- (A) $10,000,000 in the case of an offense described in paragraph (1) or (4); and (B) $20,000,000 in the case of an offense described in paragraph (2) or (3).

(c) Civil Remedies.-- (1) In general.--The district courts of the United States shall have jurisdiction to prevent and restrain violations of this section by issuing appropriate orders, including-- (A) ordering a person (convicted of an offense under this section) to divest any interest, direct or indirect, in any enterprise used to commit or facilitate the commission of the offense, or to destroy, or to mutilate and sell as scrap, aircraft material or part inventories or stocks; (B) imposing reasonable restrictions on the future activities or investments of any such person, including prohibiting engagement in the same type of endeavor as used to commit the offense; and (C) ordering the dissolution or reorganization of any enterprise knowingly used to commit or facilitate the commission of an offense under this section making due provisions for the rights and interests of innocent persons.

(2) Restraining orders and prohibition.--Pending final determination of a proceeding brought under this section, the court may enter such restraining orders or prohibitions, or take such other actions (including the acceptance of satisfactory performance bonds) as the court deems proper. (3) Estoppel.--A final judgment rendered in favor of the United States in any criminal proceeding brought under this section shall stop the defendant from denying the essential allegations of the criminal offense in any subsequent civil proceeding brought by the United States.

(d) Criminal Forfeiture.-- (1) In general.--The court, in imposing sentence on any person convicted of an offense under this section, shall order, in addition to any other sentence and irrespective of any provision of State law, that the person forfeit to the United States-- (A) any property constituting, or derived from, any proceeds that the person obtained, directly or indirectly, as a result of the offense; and (B) any property used, or intended to be used in any manner, to commit or facilitate the commission of the offense, if the court in its discretion so determines, taking into consideration the nature, scope, and proportionality of the use of the property on the offense.

(2) Application of other law.--The forfeiture of property under this section, including any seizure and disposition of the property, and any proceedings relating to the property, shall be governed by section 413 of the Comprehensive Drug Abuse and Prevention Act of 1970 (21 U.S.C. 853) (not including subsection (d) of that section).

(e) Construction With Other Law.--This section does not preempt or displace any other remedy, civil or criminal, provided by Federal or State law for the fraudulent importation, sale, trade, installation, or introduction into commerce of an aircraft or space vehicle part. (f) Territorial Scope.--This section also applies to conduct occurring outside the United States if-- (1) the offender is a natural person who is a citizen or permanent resident alien of the United States, or an organization organized under the laws of the United States or political subdivision thereof; (2) the aircraft or spacecraft part as to which the violation relates was installed in an aircraft or space vehicle owned or operated at the time of the offense by a citizen or permanent resident alien of the United States, or by an organization thereof; or (3) an act in furtherance of the offense was committed in the United States.

(Added Pub. L. 106-181, title V, Sec. 506(c)(1), Apr. 5, 2000, 114 Stat.

137.)

Effective Date

Section applicable only to fiscal years beginning after Sept. 30,

1999, see section 3 of Pub. L. 106-181, set out as an Effective Date of 2000 Amendments note under section 106 of Title 49, Transportation.

Section Referred to in Other Sections

This section is referred to in section 2516 of this title.

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I do not have any certificates, but they are in sealed military packages with NSN printed on them.

i

On 10 Mar 2005 23:06:30 -0500, snipped-for-privacy@d-and-d.com (DoN. Nichols) vaguely proposed a theory ......and in reply I say!:

remove ns from my header address to reply via email

Thanks Don. I realised and posted my own correction!

[ ... ]

[ ... ]

So I saw as I continued to read. It was too late to recall the article by then -- unlike the days when I had to wait for my system to dial up my ISP and upload the current postings.

Enjoy, DoN.

[...]

Hehe, in that case maybe 55 psi. (: But seriously, some utter garbage passes through those auctions. Amusing story: a friend of mine went to a military surplus auction and bought a pallet of unsorted nuts and bolts for about $20, thinking it was a steal. Every time he tried to tighten one more than hand tight it twisted off or lost threads. Seems the military bough a heap of crap, so just dumped it into the auction. But all of 'em had those little "Grade 8" marks on top! They're a rusted heap behind his shop now.

Scary stuff. I have not had such experiences myself. When I throw away unsellable military stuff, I usually remove all hardware worth saving. I have many pounds of various fasteners. One day, I dream, I will go through all of them and sort them by thread. That day never comes.

i