HEULE COFA - Deburring of Uneven Bore Edges - Operating Principle & Tool Selection

Q: What problem does COFA solve?

COFA deburrs even and uneven bore edges, including inaccessible edge areas, without requiring workpiece turning.

Q: How does the COFA blade work on uneven bore edges?

The spring-loaded blade in the tool body lets the cutting edge follow uneven bore edges, removing the burr along with the burr root to avoid secondary burrs.

Q: How are tool and cutting parameters selected?

Use the HEULE Tool Selector to calculate the cant (unevenness) angle and determine the correct tool and blade, then apply the cutting data guide values (speed, feed, spring) based on the selected material group and unevenness amount.

Oct 22, 2026

Upload by Alex Sinclair

COFA is a HEULE deburring tool designed to reliably machine inaccessible uneven bore edges without turning the workpiece, even with challenging materials. Carbide blades with material-specific coatings provide long service life. The spring-loaded blade follows uneven bore geometry, removing burrs with the burr root to prevent secondary burr formation and producing bore edges with a defined radius. The material guide links cutting speed, feed, and spring settings to different workpiece groups.

LanguageEnglish

CategoryTechnology

FormatPDF

Pages16

Reading Time40 min

AccessFree to download

COFA

Operating principle

Maximum unevenness

Tool design

COFA process steps and application example

Cutting data guide values

Tool selector and tool tables

DE BURRING 14 COFA A stroke of genius for deburring even and uneven bore edges . Proven a thousand times over. The advantages – Your benefit Inaccessible bore edges are reliably machined without turning the workpiece, even when working with challenging materials. The carbide blades are coated in accordance with material requirements and guarantee a long service life. COFA OPERATING PRINCIPLE The COFA blade is spring-loaded in the tool body. This means that the cutting edge also follows uneven bore edges. The cutting edge removes the burr along with the burr root without creating a secondary burr. The blade pivots into the tool body as it enters the bore. The result is a bore edge deburred with a radius form. MAXIMUM UNEVENNESS COFA is designed for machining uneven bore edges. The standard blade can reliably deburr uneven edges up to α ≤18° . This corresponds to a diameter ratio (d:D) of 0.5. The range also includes blades with a clearance angle of up to 30° for greater unevenness. For larger irregularities, tools and blades from the INDIVIDUAL range, e.g. COFA-X, are used. D d D Calculation of cant angle With the HEULE Tool Selector, you can easily calculate the angle of unevenness and at the same time determine the correct tool and blade. [heule.com/en/tool-selector/cofa](heule.com/en/tool-selector/cofa) TOOL DESIGN Simple, robust, reliable. The COFA tool family is made up of two types. In the COFA C2/C3 and 4M/5M, the blade is held directly in the tool body by a split pin. With the COFA C6 to C12, a separate blade is retained and guided by a solid blade holder. Fixing strip Blade Split pin Bending spring Blade holder COFA Tool body Torx screw Operating instructions > Blade change> Spring change [heule.com](heule.com) > Service > Media & download centre COFA COFA PROCESS STEPS APPLICATION AND PROGRAMMING EXAMPLE Z+ Z- Application data Workpiece: Outside Ø 35.0 mm / inside Ø 22.0 mm Bore Ø: Ø10 .4 mm Material: P3 / steel C45 Machining: both bore edges Unevenness y: Angle 15.9° Tool and blade selection Tool: COFA C8/10 .4/H Blade: C8-M-0006-T, medium, forward and backward cutting Deburring Ø: 11.6 mm max. Outside Ø: Ø D2 = 13.2 mm (note interfering edge / inside Ø) Cutting data Cutting speed Vc: 20–60 m/min. Working feed fz: 0.1–0.3 mm/rev CUTTING DATA | | Description | Tensile str. RM /MPA | Hardness | | Spring | C2–C3 | | | COFA4M–C12 | | | | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | | | | | (HB) | (HRC) | | Vc | fz | B* | Vc | fz | B* | | P0 | Low-carbon steel, long-chipping, C <0.25% | <530 | <125 | – | H | 20–60 | 0.05–0.15 | A | 20–60 | 0.1–0.3 | T | | P1 | Low-carbon steel, short-chipping, C <0.25% | <530 | <125 | – | H | 20–60 | 0.05–0.15 | A | 20–60 | 0.1–0.3 | T | | P2 | Steel with carbon content C >0 . 25% | >530 | <220 | <25 | H | 20–60 | 0.05–0.15 | A | 20–60 | 0.1–0.3 | T | | P3 | Alloy steel and tool steel, C >0.25% | 600–850 | <330 | <35 | H | 20–60 | 0.05–0.15 | A | 20–60 | 0.1–0.3 | T | | P4 | Alloy steel and tool steel, C >0.25% | 850–1400 | 340–450 | 35–48 | S | 20–40 | 0.05–0.15 | A | 20–40 | 0.1–0.3 | T | | P5 | Ferritic, martensitic and stainless
PH steel | 600–900 | <330 | <35 | S | 15–30 | 0.05–0.15 | A | 15–30 | 0.1–0.3 | T | | P6 | High-strength ferritic, martensitic and PH stainless steel | 900–1350 | 350–450 | 35–48 | Z | 15–30 | 0.05–0.15 | A | 15–30 | 0.1–0.3 | T | | M1 | Austenitic stainless steel | <600 | 130–200 | – | Z | 10–20 | 0.05–0.15 | A | 10–20 | 0.1–0.3 | T | | M2 | High-strength austenitic stainless steel | 600–800 | 150–230 | <25 | Z1 | 10–20 | 0.05–0.15 | A | 10–20 | 0.1–0.3 | T | | M3 | Duplex stainless steel | <800 | 135–275 | <30 | Z1 | 15–30 | 0.05–0.15 | A | 15–30 | 0.1–0.3 | T | | K1 | Cast iron | 125–500 | 120–290 | <32 | H | 30–80 | 0.05–0.15 | A | 30–80 | 0.1–0.3 | T | | K2 | Ductile cast iron up to medium strength | <600 | 13

FAQs

What problem does COFA solve?

COFA deburrs even and uneven bore edges, including inaccessible edge areas, without requiring workpiece turning.

How does the COFA blade work on uneven bore edges?

The spring-loaded blade in the tool body lets the cutting edge follow uneven bore edges, removing the burr along with the burr root to avoid secondary burrs.

How are tool and cutting parameters selected?

Use the HEULE Tool Selector to calculate the cant (unevenness) angle and determine the correct tool and blade, then apply the cutting data guide values (speed, feed, spring) based on the selected material group and unevenness amount.

Oct 22, 2026

Upload by Alex Sinclair