Iscar 3800138 Threading Toolholder Internal Left Hand

Product Description

The ISCAR 3800138 is an indexable threading toolholder designed for internal threading operations. Part of the IscarThread series, it features a left-hand orientation and a square shank measuring 0.625 x 0.625 inches. The toolholder uses a screw-clamping method to secure the threading insert and has an overall length of 5.0 inches. With a minimum bore diameter of 0.354 inches, it is suited for threading smaller internal bores in production and job-shop turning operations. The SI toolholder style is a standard configuration for CNC and manual lathes. Installation and setup are performed by machinists and tool-and-die professionals.

This toolholder is used in internal threading applications on CNC lathes and turning centers where left-hand thread profiles are required. The 0.625 x 0.625 inch shank fits standard square-shank tool blocks and quick-change toolpost systems. A shank length of 4.74 inches and head length of 0.71 inches provide the reach needed for moderate-depth boring and threading work. The unit does not include through-coolant capability, making it straightforward to set up on machines without internal coolant delivery at the turret.

Key Features

• Left-hand internal threading orientation for left-hand thread profiles
• Screw-clamp insert holding method for secure, repeatable indexing
• 0.625 x 0.625 inch square shank fits standard tool blocks
• Minimum bore diameter of 0.354 inches for small-bore internal threading
• Maximum depth of cut of 0.71 inches
• No coolant-through requirement — compatible with dry or flood-coolant setups

Compatibility

Designed for use with compatible IscarThread series indexable threading inserts. Consult the ISCAR IscarThread catalog to confirm correct insert grade, thread profile, and pitch range before use.

Installation Notes

Installation is performed by a qualified machinist on a CNC or manual lathe. Power down and de-energize the machine and confirm the spindle is fully stopped before changing or indexing the insert. Secure the shank firmly in the tool block to the torque specification listed in the machine tool documentation. Verify minimum bore clearance against the 0.354-inch minimum bore diameter before beginning the threading pass.