CoroBore 825/826 XL Fine boring tool for large diameters

Recommendations

• Choose a light-cutting insert with a positive geometry for best surface finish and close hole tolerance.
• Recommended first choice is the light cutting knife edge geometry (L-K) with nose radius 0.2 mm (0.008 inch).
• Choose a small nose radius to minimize vibrations and cutting forces.
• Choose a nose radius smaller than depth of cut
• Wiper inserts can be used at high feeds under stable conditions to increase workpiece quality and productivity levels.
• Fine boring heads CoroBore 825/826
• Always adjust from smaller diameter to larger diameter to avoid back lash.
• Unlock locking screw before adjustment, tighten afterwards

Product range

​	​	​	​	​
Boring range mm (inch)​	150-315 (5.906-12.402)​	148-315 (5.827-12.402)​	298-540 (11.732-21.260)​	538-1,275 (21.181-50.197)​
Holetolerance	IT6​	IT6​	IT6​	IT6​

 

Overview of assembly parts: 

CoroBore 825/826 XL, 825D/826D XL,
dia 150-315 mm (5.906-50.197 inch)

Conventional adaptor​	Damped adaptor​
​
1. Cartridge 2. Fine boring head 3. Slide 4. Counterweight 5. Adaptor​	1. Cartridge 2. Fine boring head 3. Slide 4. Counterweight 5. Damped adaptor​

CoroBore 825/826 XL, dia 298-540 mm (11.732-21.260 inch)​	CoroBore 825/826 XL, dia 538-1,275 m m (21.181-50.197 inch)​
​	​
1. Cartridge 2. Fine boring head 3. Slide 4. Bridge 5. Counterweight ​	1. Cartridge 2. Fine boring head 3. Slide 4. Counterweight 5. Bridge extension 6. Bridge​

Precision adjustment

Single-edge fine boring tools have adjustment  possibilities to accurately pre-set the cutting edge within microns.

CoroBore 825 XL - Diameter adjustment with new scale

• One full turn of the scale will move the insert 0.25 mm (0.010 inch) radially.
•  Adjustment with nonius scale (0.002 mm (0.00008 inch) on dia.)
• One full turn of the scale will change dia. by 0.5 mm (0.020 inch)
• Each division of the dial has 50 divisions, representing 0.010 mm (0.0004 inch)/ diameter.The vernier has 5 divisions, making it possible to adjust the diameter by 0.002 mm (0.00008 inch).
• Adjustable radial stroke on fine boring head 7.5 mm (0.295
  inch)

​CoroBore 826 XL

• Each increment adjusts the diameter by 0.002 mm (0.00008 inch), felt by a click.
• One full turn of the scale will change dia. by 0.1 mm (0.0039 inch)

​

Cartridge design

CoroBore 826 HP has a rigid interface between the fine boring head and cartridge to ensure a stable machining process.

Note: Cartridge for CoroBore^® 826 XL and CoroBore^® 825 will not fit the CoroBore^® 826 HP tool body. The CoroBore^® 826 HP cartridge interface is rotated 90 degrees. 

Cartridges for CoroTurn 107 and CoroTurn 111 inserts:

​	​	​	​
	​	​
​CoroTurn 107: TC.. 06, 09 (TC.. 1.2, 1.8)​	​CoroTurn 107: TC.. 1103 TC..22	​CoroTurn 111: TP..06,09,1103 (TC.. 1.2, 1.8, 22)​	​CoroTurn 107 CC..06, 09 (CC..1.2, 1.8)

CoroTurn 107 positive basic-shape inserts are the first choice for fine boring applications as they provide lower cutting forces than negative basic shape inserts. Large assortment of insert geometries available.

Tool holding

• Choose shortest possible adaptor
• Choose strongest possible adaptor
• If reduction is needed, use tapered version if possible
• For long overhangs (>4 x DCON), use damped adaptors
• For long overhangs, ensure rigid clamping with flange contact to spindle if possible

• Reduced tool inventory with standardized tools minimizing machine downtime
• For boring operations requiring long reach, as in large machining centres in the diameter range of 1–36 mm (0.039–1.42 inch). Deep pockets is a typical application where the Coromant EH system offers the required reach without limiting process security