Grooved studs (coloured slot studs) incorporate a transverse slot in the head for colour identification or use with adjustment tools, making them ideal for positioning and quick-fastening applications.
Grooved studs for short-cycle welding feature a slot in the head (the “colour slot”) for identification with coloured paint or for engaging adjustment tools.
Made of copper-plated grade 4.8 steel or A2-50 stainless steel, in diameters from M4 to M8 and with l1 lengths available on request.
They are ideal where angular orientation, precise positioning or visual identification of different stud types is required on the same assembly line.
1. What are grooved studs?
Grooved studs (coloured slot studs) are fasteners with a transverse slot in the stud head, directly above the welding flange. The slot has two main purposes:
- Colour identification: Coloured paint can be applied to distinguish stud types, lengths or materials quickly on a production line.
- Tool engagement: Provides a contact point for adjustment, positioning or angular-alignment tools during subsequent assembly.
They are particularly useful in manufacturing processes involving several welded-stud references where rapid visual identification is required.
2. Technical specifications
Available materials
| Material | Tensile strength (Rm) | Yield strength (Re) | Elongation |
|---|---|---|---|
| Grade 4.8 steel (copper-plated) | ≥ 420 N/mm² | ≥ 340 N/mm² | ≥ 14% |
| A2-50 stainless steel | ≥ 500 N/mm² | ≥ 210 N/mm² (Rp0.2) | ≥ 0.6 d |
Grooved-stud geometry
- Transverse slot: In the stud head, above the flange
- Flange: Diameter d2 as shown in the table, with height h1 = 0.7–1.4 mm
- Surface protection: 4–8 μm electrolytic copper coating (grade 4.8 steel)
- Thread: Cold-rolled, tolerance 6g
3. Dimension table – Grooved studs
| Thread (d1) | l1 (mm) +0.6 | d2 (mm) ±0.2 | h1 (mm) | Grade 4.8 steel item no. | A2-50 item no. |
|---|---|---|---|---|---|
| M4 | On request | 5 | 0.7-1.4 | 17-LN-04-XXX | 18-LN-04-XXX |
| M5 | On request | 6 | 0.7-1.4 | 17-LN-05-XXX | 18-LN-05-XXX |
| M6 | On request | 7 | 0.7-1.4 | 17-LN-06-XXX | 18-LN-06-XXX |
| M8 | On request | 9 | 0.8-1.4 | 17-LN-08-XXX | 18-LN-08-XXX |
Note: Replace “XXX” in the item number with the l1 length (example: 17-LN-05-030 for M5 × 30 mm). l1 dimensions are available on request.
l2 (length after welding) depends on l1 and the welding energy.
4. Welding-gun compatibility
Grooved studs are compatible with PHM-10, GD 12sc and PHM-1A welding guns, using the following chucks according to diameter:
| Diameter (d1) | l2 (projected length) | Chuck / nut (item no.) |
|---|---|---|
| M4 / 4 mm | l2 ≤ 40 / l2 > 40 | 82-50-004 |
| M5 / 5 mm | l2 ≤ 40 / l2 > 40 | 82-50-005 |
| M6 / 6 mm | l2 ≤ 40 / l2 > 40 | 82-50-006 |
| M8 / 8 mm | l2 ≤ 40 / l2 > 40 | 82-50-008 |
5. Typical applications
- Visual identification on assembly lines: Different slot colours distinguish lengths, materials or destinations
- Angular positioning: The slot helps align components in a specific orientation
- Fastening with adjustment tools: Engagement of spanners or positioning tools during assembly
- Domestic appliances: Identification of earth points or special fastenings
- Automotive: Visual differentiation on chassis and structures
6. Advantages of grooved studs
- Quick identification: Reduces errors on production lines with multiple references
- Precise positioning: The slot provides an angular reference
- Full compatibility: Same mechanical performance as standard threaded studs
- Customisable: Colours available on request
- No significant additional cost: The slot is incorporated during cold forming
7. Customisation options
- Identification colour: Red, blue, green, yellow, white or to customer specification
- l1 lengths: Any size on request
- Material: Copper-plated grade 4.8 steel, A2-50, 1.4571 or other materials on request
- Surface protection: Treatments other than standard copper plating
8. Practical recommendations
- Define an internal colour code for the different stud types
- Request samples to check colour visibility under the plant lighting conditions
- For angular-positioning applications, specify the slot orientation relative to the flange
- Check delivery times for special lengths or colours
- For high-temperature environments, verify the resistance of the colourant used
© 2026 BEARFIX® – All rights reserved. Grooved studs comply with DIN EN ISO 13918 and DIN EN ISO 14555. l1 dimensions are available on request.