Micro 100 QTH-408 Boring Grooving Bar Holder

Product Description

The MICRO 100 QTH-408 is a boring and grooving bar holder engineered for precision internal machining operations. Part of the QTH series, this holder accepts a 3/8 inch (0.3750 inch) boring bar shank and features a 1.0000 inch outside diameter body with an overall length of 2.8000 inches. The head diameter measures 1.0620 inches. Built with coolant-through capability, the QTH-408 delivers cutting fluid directly to the tool tip, reducing heat and improving chip evacuation during deep-bore and grooving operations. Machinists and toolroom professionals install this holder on CNC lathes and turning centers where consistent bore geometry and tool rigidity are critical.

The QTH-408 is suited for internal grooving and boring applications on CNC turning equipment. The coolant-through design makes it especially effective in stainless steel, titanium, and other materials where heat buildup and chip packing are common problems. The 3/8 inch bore accepts standard-shank boring bars from MICRO 100 and compatible tooling lines, making it a practical choice for shops running production or prototype work that demands repeatable results.

Key Features

• Coolant-through design delivers cutting fluid directly to the cutting zone for improved tool life and chip control
• 0.3750 inch inside diameter accommodates 3/8 inch boring bar shanks
• 1.0000 inch outside diameter body for rigid, stable mounting
• 1.0620 inch head diameter for positive seating and tool positioning
• 2.8000 inch overall length supports a range of internal machining reach requirements
• Part of the QTH series for consistent tooling system integration

Compatibility

Designed as a QTH-series bar holder compatible with 3/8 inch shank boring and grooving bars used in CNC lathes and turning centers. Specific machine or tooling compatibility should be verified against your equipment and tooling system specifications.

Installation Notes

Installation should be performed by a qualified machinist or toolroom technician with the machine powered down and the spindle locked before mounting or adjusting the holder. Ensure the boring bar shank is fully seated and clamping screws are torqued per your machine tool manufacturer's specifications. Verify coolant-through passages are clear and aligned with the machine turret coolant supply before resuming operation. Inspect the holder and boring bar for runout after installation using a dial indicator before taking a cut.