Retention Knobs

High Tensile Strength Knobs

Retention knob tensile strength improved by utilizing tool steel (H13) or die steel. Tool holders may be pulled out of the machine spindle at high speeds due to strong centrifugal forces. High tensile strength retention knobs are recommended to protect against this possibility.

Retention Knobs

Utilizes Hardened Alloy Steel with High Nickel Content or Die Steel (H13)

Utilizes Hardened Alloy Steel with High Nickel Content or Die Steel (H13)

  • Improved tensile strength
  • Roll threaded
  • Smooth surface prevents notching effect

  • Available for CAT & BT holders
  • Laser marking for manufacturer ID
  • Large selection for specific machine models

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Retention Knobs
CV/BCV 40 & 50
BT/BBT 30, 40, & 50

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Typical Problems Are Due to Material and Purity

Most breakage occurs due to impurities in the material. Impurities eventually become cracks due to strong cutting and vibration forces. Other reasons for breakage are caused by dents created from ball clamp retention systems, compared to dual contact collet-type systems. Coolant alkaline levels will also contribute to shortened life span.

BIG Daishowa pullstuds are 98% pure and contain no lead. Our pullstuds have a high nickel alloy content which provides up to 30% higher strength than those not containing nickel.

Additionally, BIG pullstuds are roll threaded which provides 30% higher strength and excellent thread quality, compared to others which are cut threaded.

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Proper Techniques for Assembly

  • Always use a proper tool assembly device to install and tighten pullstuds

  • Follow torque specs - do not over tighten

  • Use a designated torque wrench - not "cheater bars"

  • Always apply thread adhesive to prevent loosening

  • When changing cutting tools, always double check pullstud tightness

  • Pullstuds are consumable items, regularly inspect and replace