Tooling & Workholding

Toolholders

The Toolholder is the essential connection between the machining center and the cutting tool. The toolholder fits into and is secured by the machining center’s spindle, and in turn secures the cutting tool such as a drill or end mill by clamping onto its shank. The taper of the toolholder matches the toolholder interface of the particular spindle. Toolholder tapers are often conical, including CAT and BT taper specifications. A different kind of taper, HSK, is not tapered at all, but instead includes a variety of flanges for securely locking the toolholder in place. Toolholders use different mechanisms for clamping the tool. A set screw can clamp onto a corresponding flat in the tool’s shank. Or, a collet can be compressed around the tool by tightening a nut that also surrounds the tool. More unusual clamping mechanisms include hydraulic toolholders, which compress a bladder of hydraulic fluid, as well as shrink fit toolholders, which clamp and release the tool by heating and cooling the toolholder’s metal to take advantage of thermal expansion and contraction. Other toolholder types use still other methods of clamping. Various clamping mechanisms aim to provide not just secure holding of the tool, but also tool concentricity to the centerline of the spindle that is accurate to a level of runout error appropriate to the tool and the machining process.

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Featured Zone Content

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Video: Balancing Tools And Toolholders


This video provides both the argument and methodology for performing offline balancing of tool/toolholder assemblies for high speed machining centers.



Angle Heads Feature Twin or Double Twin Sets of Machined Angular Contact Bearings

By: Lori Beckman (editor)
Heimatec has developed a line of standard and custom angle heads, available in all popular sizes and styles to accommodate today’s machine tools and CNC machining center builders. 

High Torque Retention Knobs in High Strength Steel

By: Lori Beckman (editor)
JM Performance Products offers high torque retention knobs in high strength steel.  Manufactured from 9310 steel, JM’s high torque-high strength knobs are 40 percent stronger than standard knobs, the company says.

Tooling with Adjustable Overhang Length Mechanism

By: Lori Beckman (editor)
NTK Cutting Tools continues to expand its line of Swiss tools with Stick Duo Splash.

Multi-Pocket Selectable Toolholder Speeds Insert Indexing

By: Edited by Stephanie Monsanty
Modern Industries’ mPower SpinSelect multi-pocket selectable toolholder is designed to promote productivity and consistency by decreasing downtime for tool and insert setups and change-overs.

Coolant-Through Toolholders Eliminate External Coolant Line Challenges

By: Lori Beckman (editor)
Coolant aimed directly at the cutting edge and keeping it there for the full length of the cut is now available for every style of toolholder used in a Hydromat.


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