Retention Knobs

Retention Knobs — New & Used

Retention knobs (also known as pull studs) secure tool holders in CNC machine spindles, providing precision clamping force, repeatable positioning, and safe high-speed operation of milling, drilling or tapping tools. They are vital for any high-precision machining setup.

At Surplus Select, we stock a variety of new and used OEM retention knobs compatible with popular tool-holding systems—such as CAT, BT, HSK and V-Flange—and from top brands. Our daily-updated surplus inventory gives machine shops and MRO teams access to precision tool-holding components at reduced cost.

Price Match — We match any authorized distributor on identical in-stock parts, so you can source parts at surplus pricing with distributor-level assurance.

Trade-In Credit — Have quality new surplus items? Trade them in for store credit toward the parts you actually need.

Fast U.S. Shipping — Most orders ship same or next business day from our U.S. warehouse to keep your line running.

Find Your Retention Knob Fast (Search-First)

Search your part number (e.g., CAT50-E987, BT40-E941-5, HSK63-E-ISO-pull-stud).
No PN? Try specs like “CAT40 pull stud retention knob”, “BT30 retention knob mill tool holder”, or “HSK63E retention knob CNC system”.
Need a specific configuration? Add details such as tool holder interface, taper size, coolant-thru option, or balanced 12 000 rpm+.

Applications & Use Cases

CNC milling & machining centers: Proper retention knobs ensure that tool holders clamp securely in the spindle for high-precision machining operations.
High-speed tooling and tapping operations: Use balanced retention knobs to reduce vibration, improve tool life and maintain thread quality in tapping setups.
Tool room & retrofits: Replace worn or mismatched pull studs with correct retention knobs to ensure accurate tool changes and minimize spindle damage.
Production tool-holding systems: Inventory common taper sizes and knob types to keep spindle change-over times low and avoid costly downtime.
MRO & spare-stock programs: Maintain an inventory of OEM retention knobs at surplus pricing to swap during scheduled maintenance windows—ensuring your machine stays in production.

Why Buy Retention Knobs from Surplus Select

New & Used Options: OEM retention knobs and pull studs at surplus pricing for machine shops, OEMs, and MRO departments.
Broad Taper Coverage: CAT, BT, HSK, V-Flange and other common tool holder systems included in our inventory to fit a variety of machines.
Cost-Effective Tool-Holding: Surplus stock gives access to precision tool-holding components at reduced cost without sacrificing quality or compatibility.
Fast Shipping: Most orders ship same or next business day to keep your spindle operations running and minimize tool-change downtime.