Boring Tools
Duobore
Duobore consists of adapters with matching slides, shims and covers, making it possible to adapt the tool to various materials and conditions.

Adapter
The adapter has seats for two slides. When the slide screw is tightened the slide is pushed into the correct position due to the inclined surfaces of adapter and slide. There are 8 adapter sizes – 1 to 8 – covering diameters from 25 to 270 mm available with Coromant Capto and HSK couplings.

Slide
Each adapter has two setting screws – one for each slide – pushing against a stop pin in each slide. Hence it is only working when adjusting from smaller to larger diameters. Slides are available with CoroTurn 107 style CC and SC inserts and CoroTurn RC slides from diameter 69 mm in styles CN and SN.

The following entering angles are available
90°First choice for long tool assemblies and vibration prone operations
75°First choice for stack boring, interrupted cut, sand inclusions etc.
84°RC slides, for stack boring, interrupted cut, sand inclusions etc.

Cover
A cover is a slide without an insert seat. It is used as radial support for the slide and must be used when the adapter is used for single edge boring.

Shims
Shims are used to set slides to different heights. They are available for each adapter size.

Adaptability
There are three possibilities to set up Duobore for boring.




1. Twin edge boring
2. Step boring
3. Single edge boring

In twin edge boring the two slides are set to the same diameter and height. This is the basic setup for most boring applications. The feed rate is equal to feed per insert x two, fn = fz x 2. Only one insert is generating the surface. Rmax is therefore 4 times larger than fn = fz.
In step boring the two slides are set to different diameters and to different heights – to ensure that inserts are starting cutting from smallest to largest diameter – and a shim is placed between slide and adapter. Step boring is used for large radial depth of cut and in long chipping material, where the chip width can be divided into two smaller easily handled chips.
In single edge boring only one slide is used. A cover must be use to radially support the working slide. Single edge boring is used for long chipping material – more space for chips –, bottom holes and finishing.




Cutting data
Chip evacuation is critical when boring. A large volume of chips is generated in a short time, particularly in small diameter holes – therefore, surface speed should be reduced to 50% of that recommended for turning.

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Use feed/tooth (fz) according to the recommendation for the geometry being used.

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Feed per revolution
Twin edge boring fn = fz x 2
Step boring fn = fz
Single edge boring fn = fz

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Max. radial depth of cut (ap) when in twin edge- and single edge mode should be max. half of insert cutting edge length.

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Max. radial depth of cut (ap) per insert when step boring should be max. half of the insert cutting edge length. Radial depth of cut (ap) when step boring should be half of insert cutting edge length. Radial depth of cut (ap) for the two inserts will be 0.5 x 2 = insert cutting edge length.
Quick start
Diameters < 69 mm
Diameters > 69 mm
Entering angle:
90˚
84˚
Inserts:
CoroTurn 107
XCXX XXXX
08-PM 4225
08-KM 3215
08-MM 2025
T-max P
SNMG
120408-PM 4225
120408-KM 3215
120408-MM 2035
Feed fn:
0.4 mm/rev
0.6 mm/rev
Speed Vc:
160 m/min
160 m/min



© Sandvik CoromantLatest update: 11/15/2007 10:29:17 AM

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