SKH51 Equivalent HW Coating Double Stepped Shoulder Punches

These double stepped shoulder punches with a tungsten-carbide-like HW (hard coating) are used in progressive stamping and trimming tooling where repeatable punch positioning and long service life are required. The double-step shank supports stable seating in the die set, helping maintain alignment over thousands of cycles.

• Automotive connector/contact stamping: The coated working face improves wear resistance and helps reduce galling against strip material while the shank steps support consistent stripping and accuracy.
• Appliance and housing bracket trimming: Use where controlled strip release and predictable punch height are critical; head thickness referencing (noted 5 mm compatibility) aids integration with standard die blocks.
• Electrical terminal and small-part hole punching: The step geometry supports reliable location, and the available shank diameter range (D 3–25 mm) enables matching to common tool designs.

This variant is suited because the HW coating targets surface wear/galling while the double stepped shoulder enhances workholding stability for high-cycle operations.

The SKH51 equivalent option is based on M2-class high-speed steel performance for wear resistance in punching applications. Compared with the SKH40 equivalent (powdered high-speed steel), the SKH51 equivalent typically emphasizes higher hot-hardness and tool-life characteristics under repetitive cutting loads, with a practical trade-off in toughness for some geometries.

• Wear resistance: HW-coated working surfaces improve resistance to abrasion and reduce galling at the punch–strip interface.
• Hardness: SKH51/M2-type punches are commonly used in the high-HRC range to balance edge retention and cycle life (final hardness depends on the supplier’s heat-treatment process).
• Heat treatment: HSS punches are typically quenched and tempered after machining to achieve the target hardness and dimensional stability; complex stepped shoulders may require controlled finishing to maintain seating fit.

Selection between SKH40 (powdered) and SKH51 (M2) should be based on desired wear vs. toughness balance for your strip material and feed/impact conditions.

To select the correct punch size, start with the shank diameter (D) and choose a model within D = 3–25 mm. Confirm the shank diameter fit because the D tolerance is +0.005/0, m5; this impacts insertion into the punch retainer/bushing and helps maintain repeatable location.

• Tip geometry: Match the required tip dimension P (0.5–9 mm), corner radius R (0.15–3 mm), and second step tip diameter V (0.51–9.01 mm) to the die opening and edge form you need.
• Length stack-up: Select L = 40–80 mm or 40–100 mm depending on your tool height, and align to LC (30–70.1 mm) and the head thickness tolerance behavior (LCT/LMT each 30–70.1 mm) so the shoulder seats correctly.
• Functional reference: The design is described as compatible with 5 mm head thickness reference; ensure your punch holder and die block thickness align with this assumption.

If you are substituting into an existing tool, verify that the combination of tip length (F and step geometry) preserves clearance and stripping reliability.