Collection: HSS Taps
HSS Taps for CNC machine shops. Browse our full hss taps range. India-wide shipping. Bulk pricing available — message us on WhatsApp for quotes.
HSS hand and machine taps — metric (coarse and fine), BSW, UNC, UNF, BSP, and NPT thread systems. Straight flute design for chip clearance in through and blind holes.
Frequently asked questions
What is the difference between taper, plug, and bottoming taps?
Taper taps have a long lead (8-10 thread chamfer) and start the thread in a pre-drilled hole. Plug taps (also called second taps) have a shorter lead (3-5 threads) and form most of the thread. Bottoming taps have no chamfer and are used to thread all the way to the bottom of a blind hole. Through-holes need just a taper or plug; blind holes need all three used in sequence.
What drill size do I use for a metric tap?
For most ISO metric coarse pitches, the tap drill size is the thread diameter minus the pitch. Example: M6 × 1.0 uses a 5.0 mm drill; M8 × 1.25 uses a 6.8 mm drill; M10 × 1.5 uses an 8.5 mm drill. For 75% thread engagement (standard), follow a tap drill chart.
Can HSS taps thread stainless steel?
Yes, but use M35 (5% cobalt) or M42 (8% cobalt) HSS rather than standard M2 for stainless. Speed is 50-150 rpm for 6 mm taps. Heavy cutting oil mandatory — dry or soluble coolant is not enough for stainless tapping.
What is the difference between BSW, UNC, and metric threads?
BSW (British Standard Whitworth) is a legacy British standard with 55° flank angle and inch pitches. UNC (Unified National Coarse) is the American standard with 60° flank angle and inch pitches. Metric uses a 60° flank angle and mm pitches. Each requires a matching tap — they are not interchangeable.
How long does an HSS tap last?
Depends on material and cutting oil. A 6 mm M2 HSS tap in mild steel with cutting oil: typically 300-600 threads. Same tap in stainless without proper oil: 20-50 threads. Using M35 cobalt tap in stainless triples-to-quintuples life over M2.
