1388

Item 1388

OTHER: Mechanics - General - Hardware

Bolts:

AN bolts are manufactured with a tensile strength between that of a Grade 5 and a Grade 8 bolt.

	Min. Tensile Strength	Min. Yield Strength
AN	125,000 PSI	109,000 PSI
NAS	160,000 PSI	130,000 PSI
MS	Everything I have found	indicates that MS is same as AN.

The NAS bolt is 33 percent stronger than the AN bolt ~ from article on nuts and bolts

Tension:

Shear: shear strength of a bolt is usually about 60% of the tensile strength

Sectional Area:

	Dia:	Area:	Relative Area:	Tensile Strength Area:	Area of Minor Dia:	Relative Area of Minor Dia:
AN3	3/16"	0.0276 sq in	56% of 1/4"	0.02200 sq in	0.0175 sq in	53% of 1/4"
AN4	1/4"	0.0491 sq in	64% of 5/16"	0.0364 sq in	0.0326 sq in	62% of 5/16"
AN5	5/16"	0.0767 sq in	69% of 3/8"	0.0580 sq in	0.0524 sq in	65% of 3/8"
AN6	3/8"	0.1105 sq in	73% of 7/16"	0.0878 sq in	0.0809 sq in	74% of 7/16"
AN7	7/16"	0.1504 sq in	77% of 1/2"	0.1187 sq in	0.1090 sq in	73% of 1/2"
AN8	1/2"	0.1964 sq in	64% of 5/8"	0.1599 sq in	0.1486 sq in	62% of 5/8"
	5/8"	0.3069 sq in		0.256 sq in	0.240 sq in

For additional information see Machinery Handbook; [MH p.1641], [MH p.1407], [MH p.1416] , and other pages in [Fasteners] section.

My approximation; Stepping down one size from the Gyrobee for the twin rotor Electrotor on the attachment stock for the rotorhub etc will result in a weight reduction of about 33%. Is it worth it, particularly when the risk of over-tightening is greater?

Both lengths etc. http://vizsage.com/other/cheatsheets/MechanicalInfo-ANHardware.pdf

Attachment Stock:

Bolt Science

Outside Information:

Bolts (same type as Robinson's MS teetering bolts, nuts and washers etc.; SPS Technologies

Huge selection http://www.mcmaster.com/ Including Metric bolts I have not checked the grade and quality stuff yet

Miscellaneous related stuff from Rotary Wing Forum:

Stainless bolts with 316 on the head are US Grade 5 which is Metric Grade 8.8. The metric grading system confuses a lot of people.. US Grade 8 is Metric Grade 10.5.

M8 refers to an 8mm metric bolt. That is the bolt size on my 503. I don't know the length, but it depends on the prop's hub thickness. The bolt grade would be B8.

Here is some info I found on a site by Garrett D. Euler. The link is http://euler9.tripod.com/bolt-database/22.html

Metric fastener size designation nomenclature.

Metric fastener size designations always begin with capital M or MJ followed by fastener nominal diameter and thread pitch, both in units of millimeters (mm), separated by the symbol "x", as follows. M10 x 1.5-6g-S means metric fastener thread profile M, fastener nominal size (nominal major diameter) 10 mm, thread pitch 1.5 mm, external thread tolerance class 6g, and thread engagement length group S ("short"). If referring to internal thread tolerance, "g" would be capitalized. A fit between threaded parts is indicated by internal thread tolerance class followed by external thread tolerance class separated by a slash; e.g., M10 x 1.5-6H/6g.

ISO metric fastener material strength property classes (grades).

ISO metric fastener material property classes (grades) should be used. For example, fastener material ISO property class 5.8 means nominal (minimum) tensile ultimate strength 500 MPa and nominal (minimum) tensile yield strength 0.8 times tensile ultimate strength or 0.8(500) = 400 MPa. (In a few cases, the actual tensile ultimate strength may be approximately 20 MPa higher than nominal tensile ultimate strength indicated via the nominal property class code. Consult Table 10, below, for exact values.) Many anchor bolts (L, J, and U bolts, and threaded rod) are made from low carbon steel grades, such as ISO classes 4.6, 4.8, and 5.8.

Hope this helps, Alan

And more

A metric Grade 8.8 bolt is closer to a Grade 5 SAE bolt than a Grade 8.
You can get Metric Grade 10.9, which is comparable to Grade 8.
A metric 12.9 is even stronger.

An excerpt from www.motorcycle.com's tech tips :

"Metric strength designations run along the same lines as the SAE designations. Standard duty bolts have no marking, while medium strength bolts will have the number 8.8 cast into the top of the head (comparable to SAE grade five) and high strength bolts will have the number 10.9 cast into the head (comparable to SAE grade eight). In metric fasteners, you’ll also find a stronger high strength bolt, indicated by the number 12.9, which is said to exceed the strength of SAE grade eight and have minimum material tensile strength greater than 175,000 psi. Socket head cap screws, like the ones typically used on European sleds, are often these highest strength fasteners."

Last Revised: April 26, 2010