DIN 6885 parallel key — how to measure it and select a replacement?
A DIN 6885 parallel key is selected to suit the shaft and hub keyways, not solely the shaft diameter. Before purchasing, establish the width b, height h, length l, end...
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DIN 471 or DIN 472 circlip? How to select the size
DIN 471 denotes a retaining ring for a shaft, while DIN 472 denotes a ring for a bore. Before purchasing, establish the installation location, nominal shaft or bore di...
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DIN 933 and ISO 4017 — which wrench and what to check before replacement?
An M10 bolt does not always require a 17 mm wrench. For DIN 933, the nominal width across flats is 17 mm, while for ISO 4017 it is 16 mm. The same thread therefore doe...
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DIN 913–916 set screws — how to select the point
DIN 913, DIN 914, DIN 915 and DIN 916 set screws differ primarily in the end that contacts the secured component. A flat point, truncated cone point, cylindrical dog p...
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A2 or A4 bolts? What A2-70 and A4-80 mean
A4 does not automatically mean a stronger bolt than A2. In a designation such as A2-70 or A4-80, the material and mechanical property class must be read separately. Ch...
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8.8 or 10.9 bolts? Differences, markings and substitution rules
A class 10.9 bolt has higher nominal strength parameters than an 8.8 bolt. However, this does not mean they can be freely interchanged. Selection also requires checkin...
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Zinc-coated or stainless steel bolts? What to check before substitution
Do not replace a zinc-coated bolt with a stainless steel one solely because it has the same thread and a silver colour. Check the mechanical requirements, corrosion pr...
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What does DIN 931 mean? Partial thread, DIN 933 and bolt selection
DIN 931 designates a hexagon-head bolt with a partial thread. There is an unthreaded shank section between the head and the threaded end. When purchasing, check not on...
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How to choose a flat washer: dimensions, bearing area and material
A flat washer is selected according to the bolt diameter, required bearing area, thickness, and the washer's material and properties. The description “for M8” alone is...
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What does DIN 912 mean? How to identify and select a socket head cap screw
DIN 912 denotes a screw with a cylindrical head and hexagon socket, commonly called an Allen screw. The designation identifies the component's design, but does not by ...
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U-bolts — what are they, how do they work and where are they used?
What are U-bolts? They are extremely practical and robust fasteners, also known as threaded clamps, bow clamps or simply U-shaped brackets. In the simplest terms, a st...
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How to choose bolt length: a practical guide with examples
A correctly selected bolt should clamp the joined parts and provide the required thread engagement. A bolt that is too short may not span the entire joint; one that is...
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