Positive rake carbide insert bits for brake lathes

Positive Rake Carbide Insert Bits, 10-Pack | Fits Accu-Turn Brake Lathes | Part #40435

Brake Lathe Details

Replacement positive rake carbide insert bits for Accu-Turn bench brake lathes. The positive rake geometry produces a clean, low-resistance cut on modern rotor materials, finishing surfaces with minimal heat buildup and reduced cutting force. Industrial-grade carbide composition delivers extended edge life across high-volume rotor resurfacing in production shop environments.

Part #: 40435
Quantity: 10 inserts per pack
Rake geometry: Positive
Material: Industrial-grade carbide
Application: Modern rotor resurfacing on Accu-Turn brake lathes
Lathe compatibility: Accu-Turn bench brake lathes and equivalents
Function: Low-force, low-heat cutting with extended edge life
Recommended use: Cast iron and composite rotor materials

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Frequently Asked Questions (FAQs)

What brake lathe models are these bits for?

While they fit many positive rake holders, they are the primary specification for:
-Accu-Turn (Accuturn): 7700, 8911, 8922, 8944, 8989, 8991, 8993, and 8997.
-Bosch: Bench lathes utilizing the Accu-Turn style tooling system.
-Ammco: Specific combination lathes equipped with the heavy-duty positive rake tool holder upgrade.

How do I prevent "chatter" when using these bits?

These Accu-Turn Style Positive Bits are a thicker, more rigid than other bits, it is excellent at dampening vibration. However, you must ensure the tool holder seat is perfectly clean. Even a tiny metal shaving under a "thick" bit can cause it to sit unevenly, leading to the "record-player" groove effect on the rotor surface.

Does the positive rake angle make a difference for rotors?

Yes. The positive rake slope of these carbide bits are specifically designed to "shear" rather than "scrape." High-carbon and composite rotors are prone to surface tearing; the sharp, positive angle peels the metal away cleanly, which reduces heat buildup and ensures a non-directional finish that meets OEM break-in requirements.

Can I use these Accu-Turn bits on an Ammco Brake Lathe?

No. If your lathe's holder is designed for the thinner bit, the Accuturn style bits will sit too high in the seat. This throws off the "centerline" of the cut, which can lead to severe chatter, poor surface finish, and potential damage to the tool holder or the lathe arbor. Always match the bit thickness to your specific tool holder style.