What do markings on bolt heads mean?
The markings on the heads of bolts serve two different purposes: The markings can indicate who manufactured the bolt. This will vary from manufacturer to manufacturer, but is usually one, two or three characters. The markings can identify the standard to which the bolt was made.
What do the letters on top of bolts mean?
The three-letter code is the manufacturer code (for example, HKT stands for Hau Kwang Enterprises) and the numbers (if metric) or radial lines (if SAE) refer to the bolts’ strength. If there are no numbers or lines present, assume the bolt is no better than a grade 2 (low strength).
What is the head marking on a stainless steel bolt?
With bolts, stainless steel can be identified by the head marking. These markings indicate steel grade and tensile strength. When installed, stainless steel screws and bolts are known for their longevity.
What does 10 mean on a bolt head?
9: Metric grade to SAE grade comparison. Fig. 10: Metric bolts are marked with numbers that indicate the relative strength of the bolt. These numbers have nothing to do with the size of the bolt.
What is the head marking for a standard An bolt?
What do they mean? The lines on the head of a bolt indicate its grade. SAE J429 (Society of Automotive Engineers) bolts have radial lines, whereas ASTM (American Society for Testing and Materials) uses a combination of letters and numbers to indicate the grade.
What does 7 on bolt head mean?
Joined: Jul 9, 2007 Oddometer: 13,342 Location: the ‘Ha. The marks approximately correspond to the following property classes: Head Mark “4”: 4.6, 4.8, 5.6, 5.8, 6.8. Head Mark “7”: 8.8. Head Mark “8”: 9.8.
What do the head marks on fasteners mean?
Fastener manufacturers mark the heads of their bolts and screw with the identification mark. This is normally a trade mark but can be an abbreviation of their company name or a symbol. Traceability is important particularly in the case of fastener failure.
When do you use head marking in a language?
A language is head-marking if the grammatical marks showing agreement between different words of a phrase tend to be placed on the heads (or nuclei) of phrases, rather than on the modifiers or dependents. Many languages employ both head-marking and dependent-marking, and some languages double up and are thus double-marking.
What’s the difference between head marking and dependent marking?
The distinction between head-marking and dependent-marking shows the most in noun phrases and verb phrases, which have significant variation among and within languages.
What are the standards for bolt head marking?
In Part 2 of our Head Marking Series, we talk about three additional standards that deal with inch-series fasteners, ASTM A307, ASTM A354, and ASTM A193. Check it out. After that, in Part 3]