Straight Insert Tool Holder w/55° insert
This holder features a centered design (not offset to either side) and includes a 55° carbide insert, a hold-down screw, and a Torx key for installation. It has a 3/8″ square shank that fits standard 3/8″ tool posts. The straight tip design allows for general-purpose turning operations in either direction. The cutting tip is positioned 0.375″ from the bottom of the holder, which conforms to industry standards. The holder is constructed from case-hardened steel and finished with black oxide for enhanced durability and corrosion resistance.
Though more costly than traditional tools, each insert offers two usable cutting edges. When one edge becomes dull or chipped, simply rotate the insert 180° to access a new cutting surface—essentially providing two tools in one.
About the Carbide Inserts
While high-speed steel (HSS) tools remain the primary choice for miniature machine work due to their affordability and ease of resharpening, inserted-tip carbide tools offer significant advantages in specific applications. Carbide inserts excel in cutting harder materials, improving efficiency and tool life—making them invaluable in many professional machining environments.
Safety Note
Carbide inserts can produce extremely hot chips and may shatter under stress. Always wear appropriate eye protection and safety gear when using these tools.
Certain materials, such as tool steel, may form long, continuous chips that can wrap around the workpiece like steel wool. To minimize this, use a chip brush frequently or pause machining to remove chip buildup. These “bird’s nests” can ignite from hot chips, so maintain a clean workspace near the cutter.
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Insert Holder Material | Case Hardened Steel |
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Body Coating | Black Oxide |
Related products


Carbide Inserts (thread, groove)
These Carbide inserts are used in the Insert Tool Holder and are used for either threading or grooving.
Thread Cutting
- 60° threading insert for cutting outside threads (P/N 22675)
- .031" insert (P/N 2269)
- .062" insert (P/N 2270)
- .094" insert (P/N 22694)
- .125" insert (P/N 22695)
- .031" radius insert (P/N 22692)
- .062" radius insert (P/N 22693)


55° RH and LH Tool Holders w/Carbide Inserts
These tool holders are available individually in right-hand or left-hand configurations, or as a matched pair. Each holder includes a 55° carbide insert, a hold-down screw, and a Torx® key for installation. Designed with a 3/8" square shank, they fit standard 3/8" tool posts, and the insert tip is precisely 0.375" from the base of the holder—an industry-standard dimension.
The 5° offset angle of the cutting tip provides added versatility for certain operations. For example, when the holder is squared with the crosslide, it allows you to turn an outside diameter (O.D.) up to a shoulder and then finish the shoulder by backing the tool out—while maintaining proper tool clearance.
Constructed from case-hardened steel with a durable black oxide finish, these holders are built for long-lasting performance.
Although carbide insert tools are more costly than high-speed steel (HSS) tools, they offer an advantage: when the cutting edge becomes dull or chipped, you can simply rotate the insert 180° to use the second edge—essentially giving you two tools in one.
While HSS tools remain the primary choice for miniature machining due to their low cost, resharpenability, and adaptability for custom form tools, carbide insert tools are invaluable for specific applications. They maintain a sharp edge when cutting hard or abrasive materials, reduce tool wear, and allow for faster machining—reasons why they're widely used in professional machine shops.
Note: Tool orientation is named by the direction the chip exits the tool. A right-hand tool has its cutting edge on the left, and the chip peels off to the right.
Updated Note: The previously used straight-groove chip breaker insert shown in some images is no longer available. All current inserts now come with the spider web-style chip breaker as shown here.


Ceramic Insert Tool Holder
Designed for cutting hard materials like tool steel, this ceramic insert tool holder features a triangular insert mounted at a negative rake angle. The downward tilt of the insert provides proper side clearance, allowing you to use all six cutting edges—three per side—before needing a replacement. The 3/8" shank fits Sherline’s P/N 7600 tool post (not included). A clamp, hold-down screw, and 3/32" hex key are included for secure installation. Replacement inserts are available as (P/N 22659).
Why Use Ceramic Inserts?
Ceramic cutting tools are a powerful addition to the modern machinist’s toolbox. Though more brittle than high-speed steel (HSS) or carbide, ceramic inserts excel at cutting hardened steels and other tough materials, especially at higher spindle speeds. This makes them ideal for jobs that would otherwise be extremely difficult or impossible—such as turning down the shank of an end mill.
This insert’s large nose radius helps achieve an excellent surface finish, particularly when profiling.
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Each insert offers six usable cutting edges:
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Rotate 120° to access a new edge (3 per side), then
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Flip the insert for 3 more cutting points on the opposite face
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In comparison, traditional carbide inserts offer only 2–4 cutting edges, making ceramic inserts cost-effective over time, despite the higher upfront cost.
Usage Notes & Safety Information
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Ceramic inserts are brittle and should be used with proper technique to avoid chipping or breakage.
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Caution: Chips produced during cutting can be extremely hot—even red-hot. Use protective eyewear, gloves, and fire-safe clothing when operating.
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Some materials, such as tool steel, may form long, stringy chips that wrap around the part ("bird’s nest" effect).
Use a chip brush and stop the machine frequently to clear chips. These chip clusters can ignite if they come in contact with hot chips.