Collis Tool 75913 End Mill Holder R8 Taper Shank

Product Description

The COLLIS TOOL 75913 is an R8 taper shank end mill holder designed for securing end mills in manual knee mills, bed mills, and vertical machining centers equipped with an R8 spindle. The holder features a 1.25-inch bore diameter and a 2.625-inch nose diameter, with a projection of 3.125 inches from gauge line to tool tip. Overall length is 7.12 inches. This type of toolholder is a standard component in job shops and maintenance machine shops where Bridgeport-style knee mills with R8 spindles are in regular use. Installation and removal are handled by machinists and tool room technicians.

The 75913 suits vertical milling operations requiring a rigid, concentric grip on end mills up to 1.25 inches in shank diameter. It is a standard-duty toolholder appropriate for general-purpose face milling, slotting, and peripheral milling in ferrous and non-ferrous materials. Typical installation is in R8-spindle knee mills found in production machine shops, toolrooms, and vocational training facilities. No through-coolant feature is present on this holder.

Key Features

• R8 taper shank for direct spindle mounting in R8-compatible mills
• 1.25-inch bore accommodates end mills with 1.25-inch shanks
• 3.125-inch projection provides clearance for most standard end mill lengths
• 2.625-inch nose diameter for solid, vibration-resistant clamping
• 7.12-inch overall length suits typical knee mill spindle-to-table clearance
• No through-coolant port - suited for flood or mist coolant applications

Compatibility

Designed as a standard replacement or additional toolholder for vertical milling machines with an R8 taper spindle, such as Bridgeport-style knee mills and compatible imports that accept R8 tooling.

Installation Notes

Installation is performed by machinists or tool room technicians. Before inserting or removing the holder, ensure the machine spindle is fully stopped and the power disconnect is locked out per shop lockout/tagout procedures. The R8 shank is secured via the mill drawbar; tighten the drawbar to the machine manufacturer specification using the appropriate wrench - do not over-tighten or use an impact tool on the drawbar. Inspect the taper shank and spindle bore for nicks or debris before seating the holder to maintain runout accuracy.