CoroBore® 820 Rough boring tool with three-insert design

CoroBore^® 820 is your First Choice for rough boring. The comprehensive program of tool bodies, slides, shims, and cutting inserts allow CoroBore^® 820 to be configured to suit the widest possible range of applications. The same program can be utilized for productive boring, step boring, and single-edged boring. The system consists of adapters with matching slides, shims, and covers, making it possible to adapt the tool to various materials and conditions.

Benefits

• Versatile, with three different operation types in one tool
• Large standard assortment of CoroTurn^® 107 and T-Max^® P inserts
• High metal removal rate thanks to three-insert design

Features

• Short, rigid, and compact providing maximum stability
• Optional slide assemblies, individually adjustable axially and radially, resulting in reduced inventory costs.
• Cutting fluid through the tool for good chip evacuation

Application

• Dedicated geometries and grades for all materials
• Use CoroTurn^® 107 screw clamping as First Choice
• Use T-Max^® P and CoroTurn^® RC for improved economy and process security in stable conditions.

	​	​
Productive boring​​	​	​
	​	​
Step boring​​
​		​
Single-edged boring​	​	​

​	​	​	​
Counterbore	Through hole​​	Interrupted cuts​​	Blind hole​

ISO application area

 

Recommendations

• Start with a roughing geometry, unless a small depth of cut is to be taken.
• Choose a medium geometry for smaller cutting depths or improved chip breaking
• Choose CoroTurn^® 107 for lower cutting forces
• Choose negative inserts (T-Max^® P) for tough applications that require strong inserts and improved process security.
• Step boring is an effective way to increase the depth of cut without excessive vibrations

​

Product range

​
Boring range, mm (inch)​	​35–306 (1.378–12.047)
Boring depth​	4 × DC SFMS​
Hole tolerance​	IT9​

Overview of assembly parts:

​	1. Slide 2. Adapter​

Grades and geometries

 

​ ​ ​			Medium​	Roughing​	Complementary​
Positive inserts​ ​​ CoroTurn® 107 screw clamping​ ​ ​ ​ ​ ​		​	-PM / GC4225​	-PR / GC4225​	-WM / GC4215​
		​	-MM / GC2025​	-MR / GC2025​	-WM / GC2015​
		​	-KM / GC3215​	-KR / GC3215​	-WM / GC3215​
		​	-AL / H10​	-AL / H10​	-AL / GC1810​
		​	-MM / GC1105​	- MM / GC1105​	-UM / GC1115​
		​	​	​	**​
Negative inserts ​ T-Max® P, CoroTurn® RC rigid clamping ​ ​		​	-PM / GC4225​	-PR / GC4225​​	WMX / GC4215​
		​	-MM / GC2025​	-PR / GC4225​​	WMX / GC2015​
		​	-KM / GC3215​	-KR / GC3215​	WMX / GC3215​
		​	-QM / GC1105​	-QM / GC1105​	-NM / GC1115​
		​	​	​	**​

*H13A for Ti-based ISO S materials
** For recommendations on fine boring in ISO H materials, see technical guide, General Turning.
Note: Grade recommendations are valid for average conditions
For recommendations on when an alternative grade should be used, see below:

​Application ​		Toughness​	First Choice​	Wear resistance​
Roughing​​	​	GC4235​	GC4225​	GC4215​
	​	GC2035​	GC2025​	GC2015​
	​	GC4215​	GC3215​	GC3210/GC3205*​
	​	GC1115​	H10​	GC1810​
	​	GC1115/H13A​	GC1105​	GC1105​

*GC3210 nodular cast iron, GC3205 grey cast iron
For cutting data recommendations, see main catalog.

​Tool holding

Bending stiffness and torque transmissions are the most important factors when choosing a tool holder for boring operations. For best stability and hole quality, use Coromant Capto^® coupling or HydroGrip holding tools.

Coromant Capto^® coupling is the only modular tooling system designed for all metal cutting operations, including all hole making methods. The same cutting tools and adapters can be used in different applications and machines. This makes it possible to standardize one tooling system for the entire workshop. Remember the following:

• Choose the shortest possible adapter
• Choose the strongest possible adapter
• If reduction is needed, use tapered version, if possible
• For long overhangs (>4 × DCSFMS), use dampened adapters
• For long overhangs, ensure rigid clamping with flange contact to the spindle, if possible