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techtalk:ref:tools806 [2020/04/29 00:04] hippysmack [Grade Marks and Material Properties for Bolts and Screws] |
techtalk:ref:tools806 [2021/01/29 01:07] (current) hippysmack |
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[[:techtalk:menu|{{ :techtalk:gototechnicalmenu.jpg|}}]] | [[:techtalk:menu|{{ :techtalk:gototechnicalmenu.jpg|}}]] | ||
- | ====== REF: HD List of Hardware P/N & Descriptions ====== | ||
- | \\ | ||
====== Strengths Of Various Fasteners ====== | ====== Strengths Of Various Fasteners ====== | ||
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====== Grade Marks and Material Properties for Bolts and Screws ====== | ====== Grade Marks and Material Properties for Bolts and Screws ====== | ||
- | Bolts, screws and other fasteners are marked on the head with a symbol that identifies the grade of the fastener.\\ | + | Bolts, screws and other fasteners are marked on the head with a symbol that identifies the grade of the fastener. ((Machinery's Handbook 27th Edition dated 2004 pg 1508)) \\ |
The grade specification establishes the minimum mechanical properties that the fastener must meet. \\ | The grade specification establishes the minimum mechanical properties that the fastener must meet. \\ | ||
Additionally, industrial fasteners must be stamped with a registered head mark that identifies the manufacturer. \\ | Additionally, industrial fasteners must be stamped with a registered head mark that identifies the manufacturer. \\ | ||
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{{:techtalk:ref:svcproc:bolt_head_grade_markings.jpg?direct&300|}} ((drawing by Hippysmack)) \\ | {{:techtalk:ref:svcproc:bolt_head_grade_markings.jpg?direct&300|}} ((drawing by Hippysmack)) \\ | ||
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====== Mechanical Properties and Grade Markings of Nuts ====== | ====== Mechanical Properties and Grade Markings of Nuts ====== | ||
- | Three grades of hex and square nuts designated Grades 2, 5, and 8 are specified by the SAE 1995 standard covering nuts in the 1/4" to 1-1/2" diameter range. \\ | + | Three grades of hex and square nuts designated Grades 2, 5, and 8 are specified by the SAE 1995 standard covering nuts in the 1/4" to 1-1/2" diameter range. ((Machinery's Handbook 27th Edition dated 2004 pg 1509)) \\ |
Grades 2, 5, and 8 nuts roughly correspond to the SAE specified bolts of the same grade. \\ | Grades 2, 5, and 8 nuts roughly correspond to the SAE specified bolts of the same grade. \\ | ||
Additional specifications are given for miscellaneous nuts such as hex jam nuts, hex slotted nuts, heavy hex nuts, etc. \\ | Additional specifications are given for miscellaneous nuts such as hex jam nuts, hex slotted nuts, heavy hex nuts, etc. \\ | ||
Generally speaking; use nuts of a grade equal to or greater than the grade of the bolt being used. \\ | Generally speaking; use nuts of a grade equal to or greater than the grade of the bolt being used. \\ | ||
- | Grade 2 nuts are not required to be marked, however, all grades 5 and 8 nuts in the 1/4" to 1-1/2" range must be | + | * Grade 2 Nuts: |
- | marked in one of three ways: \\ | + | * Grade 2 nuts are not required to be marked. |
- | Grade 5 nuts may be marked with a dot on the face of the nut and a radial or circumferential mark at 120° counterclockwise from the dot. \\ | + | * Grade 5 Nuts (1/4" to 1-1/2" range): |
- | Or a dot at one corner of the nut and a radial line at 120° clockwise from the nut, or one notch at each of the | + | * A dot on the face of the nut and a radial or circumferential mark at 120° counterclockwise from the dot. |
- | six corners of the nut. \\ | + | * Or a dot at one corner of the nut and a radial line at 120° clockwise from the nut. |
- | Grade 8 nuts may be identified by a dot on the face of the nut with a radial or circumferential mark at 60° counterclockwise from the dot. \\ | + | * Or one notch at each of the six corners of the nut. |
- | Or a dot at one corner of the nut and a radial line at 60° clockwise from the nut, or two notches at each of the six | + | * Grade 8 Nuts (1/4" to 1-1/2" range): |
- | corners of the nut. \\ | + | * A dot on the face of the nut with a radial or circumferential mark at 60° counterclockwise from the dot. |
+ | * Or a dot at one corner of the nut and a radial line at 60° clockwise from the nut. | ||
+ | * Or two notches at each of the six corners of the nut. | ||
====== Detecting Counterfeit Fasteners ====== | ====== Detecting Counterfeit Fasteners ====== | ||
- | Fasteners with markings identifying them as a specific grade or property class are counterfeit if they don't meet standards established for that class. \\ | + | Fasteners with markings identifying them as a specific grade or property class are counterfeit if they don't meet standards established for that class. ((Machinery's Handbook 27th Edition dated 2004 pg 1509)) \\ |
Counterfeit fasteners may break unexpectedly at smaller loads than expected. \\ | Counterfeit fasteners may break unexpectedly at smaller loads than expected. \\ | ||
Generally, these fasteners are made from the wrong material or they are not properly strengthened during manufacturing. \\ | Generally, these fasteners are made from the wrong material or they are not properly strengthened during manufacturing. \\ |