M35 Cobalt HSS Drill Bit Kit (21pcs) – 135° Split Point, Fractional Sizes with Index Case
21-Piece Cobalt Drill Bit Set (M35 HSS-Co) – 135° Split Point, Twist Bits for Metal
Built for shops that can’t afford to slow down, the XRTOOLS 21-Pc M35 Cobalt Drill Bit Set combines a 135° split-point tip with HSS-Co (M35, ~5% cobalt) substrate to slice through tough metals with less walking, lower thrust, and cleaner holes. Each bit is precision-ground for concentricity, then matched to a labeled index case so the right size is always within reach—on the bench, in the truck, or at the jobsite.
| Feature | Details |
|---|---|
| Material | HSS-Co M35 (~5% cobalt), fully ground |
| Tip Geometry | 135° split point (self-centering; reduced walking) |
| Flutes | Precision-ground twist flutes, optimized chip evacuation |
| Length Type | Jobber length |
| Shank | Straight round; fits 3-jaw chucks |
| Finish | Bright ground (options: black oxide, black & gold) |
| Hardness | ≥ HRC 66 (typical for M35 after heat treatment) |
| Recommended Materials | Stainless (304/316), carbon & alloy steel, cast iron, brass/bronze |
| Coolant Use | Cutting oil recommended on stainless & thick stock; peck for heat control |
| Included Count | 21 pieces (fractional sizes; see map below) |
| Case | Heavy-duty metal index case with size-stamped wells |
| Compliance | Manufactured to tight concentricity and run-out tolerances |
Why it performs (multi-angle benefits)
Cut quality & accuracy: The 135° split point self-centers and reduces burrs, improving hole roundness and surface finish in steel and stainless.
Throughput & uptime: Cobalt hot-hardness resists edge softening at elevated temps, enabling slower change-outs and fewer regrinds.
Longevity & TCO: M35’s wear resistance + fully ground flutes deliver long life, lowering cost per hole over standard HSS.
Operator friendly: Lower feed pressure and reduced walking mean faster starts and safer handling on hand drills and presses.
Shop-ready packaging: Metal index case with clear size callouts speeds tool selection and inventory counting.
Typical applications
Metals: stainless (304/316), carbon steel, alloy steel, cast iron, and hard non-ferrous (bronze/brass).
Fabrication & MRO: brackets, channel, plate, enclosures, frames, handrails, fastener prep.
Electrical/HVAC/Auto: panel work, conduit knockouts (pilot), mounting holes, vehicle upfits.
Note: For thick austenitic stainless, use cutting oil and lower RPM; peck to manage chips and heat.
Size Map (Fractional → Decimal → Metric) – 21-Pc Set
| Size (in) | Decimal (in) | Metric (mm) |
|---|---|---|
| 1/16 | 0.06250 | 1.59 |
| 5/64 | 0.07812 | 1.98 |
| 3/32 | 0.09375 | 2.38 |
| 7/64 | 0.10938 | 2.78 |
| 1/8 | 0.12500 | 3.17 |
| 9/64 | 0.14062 | 3.57 |
| 5/32 | 0.15625 | 3.97 |
| 11/64 | 0.17188 | 4.37 |
| 3/16 | 0.18750 | 4.76 |
| 13/64 | 0.20312 | 5.16 |
| 7/32 | 0.21875 | 5.56 |
| 15/64 | 0.23438 | 5.95 |
| 1/4 | 0.25000 | 6.35 |
| 17/64 | 0.26562 | 6.75 |
| 9/32 | 0.28125 | 7.14 |
| 19/64 | 0.29688 | 7.54 |
| 5/16 | 0.31250 | 7.94 |
| 21/64 | 0.32812 | 8.33 |
| 11/32 | 0.34375 | 8.73 |
| 23/64 | 0.35938 | 9.13 |
| 3/8 | 0.37500 | 9.52 |
Technical specifications
Material: M35 Cobalt HSS (≈5% Co)
Tip geometry: 135° split point (self-centering)
Flutes: Fully ground twist, optimized for chip evacuation
Shank: Straight round, 3-jaw chuck compatible
Finish: Bright ground; black oxide or black-and-gold options available
Recommended use: Ferrous & non-ferrous metals; use lubricant/coolant for stainless & thick stock
Speed & feed guidance (rule-of-thumb)
Mild steel: ~15–25 m/min surface speed (reduce for larger diameters)
Stainless: ~8–12 m/min with cutting oil; peck drill to control heat
Aluminum/brass: ~60–90 m/min; light oil optional
Packaging for pros (and wholesale)
Index case: Heavy-duty metal box with size-stamped wells
Retail & bulk: Shrink-sleeved case for retail; master cartons for distributors
OEM options: Private label, custom assortments (metric/imperial mix), custom finish, barcode + bilingual labels (EN/RU)
FAQ
Q1. Will these drill stainless steel?
Yes—M35 cobalt and a 135° split point are made for stainless. Use lower RPM and cutting oil for best life.
Q2. Are they impact-driver compatible?
These have round shanks for 3-jaw chucks. For hex/impact use, ask about our hex-shank SKUs.
Q3. Can I resharpen them?
Absolutely. M35 grinds cleanly; keep the split-point geometry when regrinding.
Q4. What if I need other sizes or step increments?
We support custom assortments and full fractional or metric maps for OEM/wholesale.
Q5. Do you offer black & gold finish?
Yes—black oxide and black-and-gold finishes are available upon request.
Get in Touch
Have questions about our products or want to discuss a custom order? Our team is ready to help you.