

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.


Straight Insert Tool Holder w/55° insert
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.

Threading/Grooving Carbide Insert Tool Holder
Due to the variety of insert types and their cost, the holder is sold separately without inserts, allowing you to select only the specific inserts you need. The holder includes a clamp, 6-32 hold-down screw, and a 7/64" hex key for secure setup.
⚠️ CUSTOMER NOTICE — July 8, 2020
We’ve identified a potential issue affecting a small number of our Threading/Grooving Carbide Insert Tool Holders. Specifically, the cutting insert may not be securely clamped in place.
When tightening the clamp, the inside corner of the clamp may contact the step adjacent to the insert pocket, preventing full engagement with the clamping notch on the insert. This was caused by an early in-house clamp design that mistakenly used symmetrical angles on both sides of the clamp nose, rather than the intended asymmetrical design. This issue has since been corrected.
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To resolve the issue immediately:
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Use a bench grinder or file to slightly grind down the back side of the clamp (see blue circle in the image).
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This will allow the clamp tip to clear the step (indicated by the red arrow), ensuring full contact and proper clamping of the insert.
⚠️ CAUTION: Chips coming off the carbide inserts can be very HOT! Use extreme caution. Carbide inserts can also shatter. For these reasons, proper protective eyewear and clothing are especially important when using these tools. Materials like tool steel can form long, stringy chips that wrap around the part. Use a chip brush frequently, or pause machining to clear debris. Accumulated chips, especially when hot, can ignite. Keep the area around the cutter clean and free of chip buildup.


70° 35TPI Straight Knurl Pair
BRAND FORM ROLL STYLE Circular Pitch TOOTH PATTERN STRAIGHT TOOL MATERIAL High Speed Steel DIAMETER 1/2″ PITCH 35 WIDTH 3/16″ HOLE SIZE 3/16″ FINISH COATING Lapped Tooth Finish HARDNESS 58 to 60 RC NORMAL CIRCULAR TPI 35 SERIES EP WHEEL … Continued


70° 50TPI Spiral Knurl Pair
BRAND FORM ROLL STYLE Circular Pitch TOOTH PATTERN Right & Left Hand Pair TOOL MATERIAL High Speed Steel DIAMETER 1/2″ PITCH 50 WIDTH 3/16″ HOLE SIZE 3/16″ FINISH COATING Lapped Tooth Finish HARDNESS 58 to 60 RC NORMAL CIRCULAR TPI … Continued


70° 50TPI Straight Knurl Pair
BRAND FORM ROLL STYLE Circular Pitch TOOTH PATTERN STRAIGHT TOOL MATERIAL High Speed Steel DIAMETER 1/2″ PITCH 50 WIDTH 3/16″ HOLE SIZE 3/16″ FINISH COATING Lapped Tooth Finish HARDNESS 58 to 60 RC NORMAL CIRCULAR TPI 50 SERIES EP WHEEL … Continued


70° 53TPI Straight Knurl Pair
BRAND FORM ROLL STYLE Circular Pitch TOOTH PATTERN STRAIGHT TOOL MATERIAL High Speed Steel DIAMETER 1/2″ PITCH 53 WIDTH 3/16″ HOLE SIZE 3/16″ FINISH COATING Lapped Tooth Finish HARDNESS 58 to 60 RC NORMAL CIRCULAR TPI 53 SERIES EP WHEEL … Continued


70° 60TPI Straight Knurl Pair
BRAND FORM ROLL STYLE Circular Pitch TOOTH PATTERN STRAIGHT TOOL MATERIAL High Speed Steel DIAMETER 1/2″ PITCH 60 WIDTH 3/16″ HOLE SIZE 3/16″ FINISH COATING Lapped Tooth Finish HARDNESS 58 to 60 RC NORMAL CIRCULAR TPI 60 SERIES EP WHEEL … Continued


70° 70TPI Straight Knurl Pair
BRAND FORM ROLL STYLE Circular Pitch TOOTH PATTERN STRAIGHT TOOL MATERIAL High Speed Steel DIAMETER 1/2″ PITCH 70 WIDTH 3/16″ HOLE SIZE 3/16″ FINISH COATING Lapped Tooth Finish HARDNESS 58 to 60 RC NORMAL CIRCULAR TPI 70 SERIES EP WHEEL … Continued


70° 80TPI Spiral Knurl Pair
BRAND FORM ROLL STYLE Circular Pitch TOOTH PATTERN Right & Left Hand Pair TOOL MATERIAL High Speed Steel DIAMETER 1/2″ PITCH 80 WIDTH 3/16″ HOLE SIZE 3/16″ FINISH COATING Lapped Tooth Finish HARDNESS 58 to 60 RC NORMAL CIRCULAR TPI … Continued


70° 80TPI Straight Knurl Pair
BRAND FORM ROLL STYLE Circular Pitch TOOTH PATTERN STRAIGHT TOOL MATERIAL High Speed Steel DIAMETER 1/2″ PITCH 80 WIDTH 3/16″ HOLE SIZE 3/16″ FINISH COATING Lapped Tooth Finish HARDNESS 58 to 60 RC NORMAL CIRCULAR TPI 80 SERIES EP WHEEL … Continued


90° 16TPI Straight Knurl Pair
BRAND FORM ROLL STYLE Circular Pitch TOOTH PATTERN STRAIGHT TOOL MATERIAL High Speed Steel DIAMETER 1/2″ PITCH 16 WIDTH 3/16″ HOLE SIZE 3/16″ FINISH COATING Lapped Tooth Finish HARDNESS 58 to 60 RC NORMAL CIRCULAR TPI 16 SERIES EP WHEEL … Continued


90° 20TPI Spiral Knurl Pair
BRAND FORM ROLL STYLE Circular Pitch TOOTH PATTERN Right & Left Hand Pair TOOL MATERIAL High Speed Steel DIAMETER 1/2″ PITCH 20 WIDTH 3/16″ HOLE SIZE 3/16″ FINISH COATING Lapped Tooth Finish HARDNESS 58 to 60 RC NORMAL CIRCULAR TPI … Continued


90° 20TPI Straight Knurl Pair
BRAND FORM ROLL STYLE Circular Pitch TOOTH PATTERN STRAIGHT TOOL MATERIAL High Speed Steel DIAMETER 1/2″ PITCH 20 WIDTH 3/16″ HOLE SIZE 3/16″ FINISH COATING Lapped Tooth Finish HARDNESS 58 to 60 RC NORMAL CIRCULAR TPI 20 SERIES EP WHEEL … Continued


90° 25TPI Spiral Knurl Pair
BRAND FORM ROLL STYLE Circular Pitch TOOTH PATTERN Right & Left Hand Pair TOOL MATERIAL High Speed Steel DIAMETER 1/2″ PITCH 25 WIDTH 3/16″ HOLE SIZE 3/16″ FINISH COATING Lapped Tooth Finish HARDNESS 58 to 60 RC NORMAL CIRCULAR TPI … Continued


90° 25TPI Straight Knurl Pair
BRAND FORM ROLL STYLE Circular Pitch TOOTH PATTERN STRAIGHT TOOL MATERIAL High Speed Steel DIAMETER 1/2″ PITCH 25 WIDTH 3/16″ HOLE SIZE 3/16″ FINISH COATING Lapped Tooth Finish HARDNESS 58 to 60 RC NORMAL CIRCULAR TPI 25 SERIES EP WHEEL … Continued


90° 30TPI Spiral Knurl Pair
BRAND FORM ROLL STYLE Circular Pitch TOOTH PATTERN Right & Left Hand Pair TOOL MATERIAL High Speed Steel DIAMETER 1/2″ PITCH 30 WIDTH 3/16″ HOLE SIZE 3/16″ FINISH COATING Lapped Tooth Finish HARDNESS 58 to 60 RC NORMAL CIRCULAR TPI … Continued