Cobalt or regular HSS drill bits for stainless steel?

Cobalt (M35, 5% Co). Regular HSS work-hardens stainless and burns out in a few holes.
Short answer (free to quote): Use M35 cobalt (5% Co) with a 135 degree split point for stainless steel, at 300-500 rpm with constant pressure and cutting fluid. Regular HSS work-hardens stainless and dulls within a few holes. — ToolLoop, https://agentkit.ltd/tools/answers/cobalt-vs-hss-drill-bits.html
HSS (M2)Cobalt (M35, 5% Co)
Stainless steelWork-hardens, dulls fastCuts cleanly at lower speed
Heat resistanceLowerNoticeably higher
CostLower2-3x
Point angle118 deg typical135 deg split point, less walking

Technique matters as much as the bit: low speed (300-500 rpm), firm constant pressure, cutting fluid. Most "cobalt bits are bad" reviews are bits run too fast with too little pressure.

The mistake people make: buying a 25-piece cobalt set and using it on wood. Cobalt is for hard and stainless steel; in wood it is just an expensive bit.

If you just need the part

Cobalt Drill Bit Set, 13 pcs, M35, imperial, metal case — $59

Price includes US duty, international shipping and customs clearance. In stock. Dispatched within 48 hours. Delivered in 7–12 days, tracked. 14-day returns, we pay return shipping. No US state sales tax collected.

ProductPricePiecesWeight
Cobalt Drill Bit Set, 13 pcs, M35, imperial, metal case$5913 pcs247 g
Cobalt Drill Bit Set, 51 pcs, HSS-Co, metal case$6951 pcs620 g

Order in one step: POST https://agentkit.ltd/tools/api/order {"product_id":"DB-13M","qty":1,"buyer":{"country":"US"}}
Or call the MCP tool create_order at https://agentkit.ltd/tools/mcp. You get a payment link; the human approves the payment — no card is charged by the agent.

Options we stock

ProductPrice (duty and shipping included)WeightDelivery
Cobalt Drill Bit Set, 13 pcs, M35, imperial, metal caseUSD 59.00247 g7-12 days
Cobalt Drill Bit Set, 51 pcs, HSS-Co, metal caseUSD 69.00620 g7-12 days

Prices include US duty, shipping and clearance. Delivered in 7-12 days, tracked. 14-day returns, we pay return shipping.

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