How to Choose a DIN 1587 Cap Nut for Metric Assemblies
A practical selection guide for the DIN 1587 high-type domed cap nut, covering thread fit, internal depth, material, finish, dimensions, and application suitability.
Metric coarse thread and mating bolt: confirm the required metric size, 6H thread class, and compatibility with ISO 4017 or DIN 933 bolts.
Internal clearance and dimensions: compare bolt projection with the minimum internal depth t, then confirm across-flats s and total height h for the selected size.
Material, grade, construction, and finish: specify carbon steel, SS304, SS316, or brass; Class 6 or Class 8; one-piece or two-piece construction; and the required surface finish.
Application and appearance: use the high-type domed form for exposed metric joints in architectural steelwork, automotive trim, or consumer electronics where a rounded finished joint is required.
A cap nut must match the bolt, provide enough clearance inside the dome, and suit the joint environment. For buyers specifying a metric decorative or protective joint, the DIN 1587 high-type domed design is the applicable option in this selection.
Start with the joint and bolt
This high-type domed nut uses metric coarse threads with a 6H thread class. Its primary bolt matches are ISO 4017 and DIN 933. Check the bolt diameter, thread pitch, and the amount of thread that will project beyond the assembled joint before choosing a size.
The design suits exposed metric joints where the finished assembly needs a rounded top and coverage over protruding bolt threads. It fits architectural steelwork, automotive trim, and consumer electronics assemblies where the visible joint needs a clean finish.
Check internal clearance before ordering
The dome has a deep internal cavity, but the available depth changes with size. Use the minimum internal depth, listed as t, when comparing the part with the bolt projection. The dimensional range includes M4 through M20:
| Size | Across flats, s (mm) | Total height, h (mm) | Minimum depth, t (mm) |
|---|---|---|---|
| M4 | 7 | 8 | 5.26 |
| M5 | 8 | 10 | 7.21 |
| M6 | 10 | 12 | 7.71 |
| M8 | 13 | 15 | 10.65 |
| M10 | 17 | 18 | 12.65 |
| M12 | 19 | 22 | 15.65 |
| M14 | 22 | 25 | 17.65 |
| M16 | 24 | 28 | 20.58 |
| M20 | 30 | 34 | 25.58 |
For an M8 bolt, compare the bolt projection with the M8 part's 10.65 mm minimum depth. Its 13 mm across-flats dimension also gives the purchasing and assembly team a wrench-size reference. Apply the same check to every size instead of selecting by nominal thread diameter alone.
Match material and finish to the assembly
The series is available in carbon steel, SS304, SS316, and brass, with Class 6 and Class 8 options. Finish choices include chrome plating, nickel, zinc plating, plain light-oil surface, PVD gold, and brass polish. Select the material and finish together with the joint's appearance and exposure requirements.
Chrome-plated and high-mirror finishes suit visible assemblies where surface appearance is part of the specification. Nickel and zinc-plated options provide additional finish choices for appearance and corrosion considerations. SS304, SS316, carbon steel, and brass give buyers different material paths for the assembly design. Send the required material, grade, finish, and size as one line item so the supplier can quote the intended configuration.
Consider one-piece or two-piece construction
The range includes one-piece and two-piece construction. This is a useful specification check for a repeat assembly or a replacement part. Keep the construction requirement with the thread size, material, grade, and finish in the purchase description.
DIN 986 is identified as a nylon-lock cap alternative, while DIN 917 is the low-type alternative. Choose DIN 1587 when the application calls for the taller domed form and its listed internal depth range.
Selection recommendation
Choose the DIN 1587 high-type domed cap nut for an exposed metric joint that needs a rounded visible finish and coverage over the bolt end. It fits buyers specifying ISO 4017 or DIN 933 bolts in architectural steelwork, automotive trim, or consumer electronics, provided the selected size, material, grade, construction, and finish match the assembly.
Before requesting a quotation, send the bolt standard, thread size, measured projection, required s and h dimensions, material, grade, construction, finish, and order quantity. This lets the supplier match the part to the actual joint rather than to the keyword alone.
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