CNC Tool Holder Pull Stud (Retention Knob) - BT/SK/OTT Series

CNC Tool Holder Pull Stud (Retention Knob) - BT/SK/OTT Series

High-precision alloy steel pull studs for CNC tool holders, available in standard/coolant/through-coolant types, compatible with BT30/BT40/BT50/BT60/SK/OTT machining center spindles.
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Description

CNC tool holder pull studs (retention knobs) are manufactured from high-strength alloy steel with overall quenching and precision grinding, the essential connecting accessories for mounting tool holders on CNC machining center spindles.
  1. High-strength alloy steel construction with hardened surface provides excellent tensile strength and fatigue resistance, capable of withstanding high-speed rotation and heavy cutting loads.
  2. Available in three main types: standard type, coolant type and through-coolant type, meeting different machining requirements including internal coolant delivery.
  3. Precision-machined threads and taper ensure perfect fit with tool holders and spindle interfaces, guaranteeing high clamping accuracy and stability.
  4. Complete size range covers all common BT30/BT40/BT50/BT60, SK30/SK40/SK50/SK60 and OTT40/OTT50 spindle standards.
  5. Black oxide or nickel plating surface treatment provides superior corrosion resistance and long service life.
  6. Strict quality control ensures consistent dimensions and performance, compatible with all mainstream CNC machine tool brands.

Complete Specification Table (Unit: mm)

BT Series Standard Type Pull Stud

MODEL D d1 d2 d3 L L1 L2 T KGS Price
BT30-45° 16.5 11 7 12.5 43 23 18 M12 0.04
BT40-45° 23 15 10 17 60 35 28 M16 0.1
BT50-45° 38 23 17 25 85 45 35 M24 0.3
BT60-45° 56 32 24 31 115 65 53 M30 0.4
BT30-60° 16.5 11 7 12.5 43 23 18 M12 0.04
BT40-60° 23 15 10 17 60 35 28 M16 0.1
BT50-60° 38 23 17 25 85 45 35 M24 0.3
BT60-60° 56 32 24 31 115 65 53 M30 0.4
BT30-90° 16.5 11 7 12.5 43 23 18 M12 0.04
BT40-90° 23 15 10 17 60 35 28 M16 0.1
BT50-90° 38 23 17 25 85 45 35 M24 0.3
BT60-90° 56 32 24 31 115 65 53 M30 0.4

BT Series Coolant Type Pull Stud

MODEL D D4 d1 d2 d3 L L1 L2 T KGS Price
BT30-45°W 16.5 3 11 7 12.5 43 23 18 M12 0.04
BT40-45°W 23 4 15 10 17 60 35 28 M16 0.1
BT50-45°W 38 6 23 17 25 85 45 35 M24 0.3
BT60-45°W 56 14 32 24 31 115 65 53 M30 0.4
BT30-60°W 16.5 3 11 7 12.5 43 23 18 M12 0.04
BT40-60°W 23 4 15 10 17 60 35 28 M16 0.1
BT50-60°W 38 6 23 17 25 85 45 35 M24 0.3
BT60-60°W 56 14 32 24 31 115 65 53 M30 0.4
BT30-90°W 16.5 3 11 7 12.5 43 23 18 M12 0.04
BT40-90°W 23 4 15 10 17 60 35 28 M16 0.1
BT50-90°W 38 6 23 17 25 85 45 35 M24 0.3
BT60-90°W 56 14 32 24 31 115 65 53 M30 0.4

SK Series Pull Stud

MODEL D D1 D2 d3 D4 L L1 L2 L3 L4 SW Price
SK30A 17 13 9 13 - 44 24 19 - - 14
SK40A 23 19 14 17 7 54 26 20 - - 19
SK50A 36 28 21 25 11.5 74 34 25 - - 30
SK60A 52 40 30 32 14 90 40 30 60 - 46
SK30B 17 13 9 13 - 44 24 19 - 2.3 14
SK40B 23 19 14 17 7 54 26 20 27 3 19
SK50B 36 28 21 25 11.5 74 34 25 37 4.5 30
SK60B 52 40 30 32 14 90 40 30 60 - 46

OTT Series Pull Stud

MODEL d1 d2 d4 d5 d6 L1 L2 L3 G SW KGS Price
OTT40 25 21.1 17 M16*2.0P 7 53 25.1 13.6 M16*2.0P 19 0.09
OTT50 39.6 30.2 25 M24*3.0P 7 65.1 25.1 13.3 M24*3.0P 30 0.17

Parameter Explanation

  • Model Naming :
    • BT/SK/OTT: Spindle interface standard
    • The number indicates the spindle size (e.g., BT40 = BT40 spindle)
    • 45°/60°/90°: Pull stud head angle
    • W suffix: Coolant type with internal coolant hole
    • A/B suffix: Different structural types for SK series
  • D/d1/d2/d3/d4/d5/d6 : Overall and mounting dimensions (unit: mm), corresponding to the engineering drawings
  • L/L1/L2/L3/L4 : Length dimensions (unit: mm)
  • T/G : Thread specification of the pull stud
  • KGS : Net weight per unit (unit: kg)
  • SW : Wrench size required for installation

Applications

CNC Machining

Ideal for CNC lathe, milling and machining center operations, ensuring high-precision dimensional control and reliable tool holding for mass production.

Quality Control Labs

Suitable for quality inspection departments and calibration labs, providing accurate measurement data to verify product compliance with ISO and industry standards.

Mold & Die Making

Perfect for mold and die workshops, where micron-level precision tools and gauges are essential for complex cavity machining and final inspection.

OEM/ODM Projects

Customizable solutions for OEM and ODM manufacturing partners, offering tailored measuring tools and CNC accessories to meet unique production requirements.

Automotive Manufacturing

Designed for automotive component production lines, ensuring consistent precision and durability in engine parts, transmission components and assembly processes.

Aerospace & Precision Engineering

Ideal for aerospace and defense manufacturing, where ultra-high precision instruments and reliable tool holders meet strict quality and safety requirements.

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