Shallow Hole Drilling Inserts

Kingdon Shallow Hole Drilling Inserts are indexable carbide cutting edges engineered for short-bore drilling (depths ≤ 3× diameter)​ on CNC lathes, machining centers and dedicated drilling units - the range between a solid twist drill and a deep-hole gun drill. Unlike single-flute drills, shallow drilling uses a two-insert drill body: an outer corner (OD) insert cuts the bore circumference, while an inner (ID) insert roughes the center. Both edges must synchronize on chip load, so the grade and edge prep are tuned as a matched pair, not as standalone triangles.

The program centers on three ISO drill geometries: SOMT​ (round/button, double-sided, high strength), SPMG​ (positive rhombic, sharp entry, low thrust) and WCMX​ (trigon, 3-edge economy). All fit standard U-drill / indexable drill bodies and accept internal coolant through the toolholder. Substrates are fine- to medium-grain WC with PVD TiAlN/TiCN (steel, stainless) or CVD Al₂O₃-based (cast iron) coatings, precision ground to ISO insert tolerances.

What's Different About Shallow Drilling

• Paired-edge balance: outer insert takes the peripheral cutting speed and_exit shock; inner insert runs near zero surface speed. ZZKD grades them as an OD/ID duo so wear stays even across both corners.
• Axial thrust control: positive-rake SPMG/WCMX entry edges keep thrust low on thin-wall and small-rigidity setups, avoiding drill walk at break-through.
• Double- / triple-edge economy: SOMT gives a robust double-sided button, WCMX delivers 3 usable edges, SPMG 4 - the unit cost that matters is cost per drilled hole, not per insert.
• Coolant-channel geometry: chip grooves coordinate with through-coolant holders to evacuate short, curled chips from a 1–3 D bore before they re-cut.
• Flat-bottom capability: paired inserts can interpolate and spot-face in one pass, replacing drill + counterbore on flange and manifold faces.