Micro 100 QTH-85 Boring Grooving Bar Holder

Product Description

The MICRO 100 QTH-85 is a boring and grooving bar holder designed for use with quick-change tooling systems in CNC and manual lathe applications. Built to QTH series standards, this holder accepts boring and grooving bars with a 0.1875-inch inside diameter and features a 0.5000-inch outside diameter shank. The overall length is 2.8000 inches, and the head diameter measures 0.7500 inches. A coolant-through design supports directed coolant delivery to the cutting zone, helping manage heat and chip evacuation during internal boring and grooving operations. This holder is installed by machinists and toolroom professionals in precision machining environments.

The QTH-85 is suited for internal boring and grooving operations on lathes equipped with quick-change toolpost systems. It is appropriate for both production and job-shop environments where consistent tool positioning and repeatability are required. The coolant-through capability makes it a practical choice for applications involving harder materials or deeper bores where heat management is critical to tool life and surface finish.

Key Features

• Inside diameter of 0.1875 inches for compatible boring and grooving bars
• Outside diameter of 0.5000 inches for standard quick-change toolpost fitment
• Overall length of 2.8000 inches for reach and clearance in typical lathe setups
• Head diameter of 0.7500 inches
• Coolant-through design for directed cutting fluid delivery to the cutting zone
• Part of the QTH series for consistent fitment within the MICRO 100 quick-change tooling system

Compatibility

Designed for use within the MICRO 100 QTH series quick-change tooling system, compatible with boring and grooving bars requiring a 0.1875-inch bore and a 0.5000-inch shank interface.

Installation Notes

Installation is performed by a qualified machinist following the lathe or toolpost manufacturer's setup procedures. Ensure the machine spindle is fully stopped and the lathe is powered down before changing or adjusting toolholders. Verify that the bar is seated fully and the clamping mechanism is engaged per the toolpost system specifications before resuming cuts. Coolant-through connections should be checked for proper seating and flow before operation.