Star CNC SR-20RIV Type A/B
Category: Star CNC


The SR-20RIV Type B provides exceptional performance and versatility within the 20mm class. Up to forty one tools can be mounted including six tools on the B axis tool post. Fanuc’s high specification 31i-B5 control delivers full five axis capability enabling highly complex components to be processed.

The flexibility of the SR-20RIV Type B is further enhanced by its ability to switch between guide bush mode (Swiss type) and non-guide bush mode.

The powerful sub-spindle with independent 8 station platen increases overlapped machining possibilities. The Y2 axis on the sub-spindle platen allows both cross working and front facing power tools to be mounted in any station.



  • Standard machining diameter 20mm (22.2mm optional)
  • Z1 Stroke of 205mm in Swiss mode (Guide Bush)
  • Switchable between guide bush and non-guide bush modes
  • Main spindle speed 10,000 rpm, sub-spindle speed 10,000 rpm
  • Built-in type main and sub-spindle motors for improved indexing accuracy
  • Programmable B axis for angular machining on both spindles
  • STAR MOTION CONTROL to minimize idle time
  • 8 Station sub-spindle platen for maximum overlapping
  • Two independent deep hole drilling stations (main spindle)



SR-20RIV-Kinematik 2


Standard Machine Specs SR-20RIV

Max. machining diameter Ø 20 mm (25/32 in)
Max. headstock stroke Standard 205mm (8in)
Non-guide bush type Bar dieameter x 2.5 (Max. 50mm)(Max. 1-31/32in)
Tool 5 tools on the front + 2 tools on the rear (12mm)
4-Spindle sleeve holder Number of tools Front 4 tools
Rear 2 tools
Max. drilling capability Ø 12mm(1/2in)
Max. tapping capability M10xP1.5
Power driven att. Number of tools Cross milling: 3 tools
Cartridge type: At 2 position
Number of tools (type A) Power-driven tool: At 1 position (Front 3 tools + Rear 3 tools)
Number of tools (type A) Power-driven tool with B axis: At 1 position (Front 3 tools + Rear 3 tools)
Max. drilling capability Ø 10mm(25/64in)
Max. tapping capability M8xP1.25
Rapid feed rate 35m/min-1(X1, X2, Y1, Z1, Z2) 15m/min-1(Y2)
198,000°/min (C), 27,000°/min(B): type B only
Main spindle with indexing angle C-axis control
Main spindle motor 2.2kw (continuous)/ 3.7kw (10min/25%ED)
2-spindle front sleeve holder Number of tools (sleeve) 2 tools
Max. drilling capability Ø 10mm(25/64in)
Max. depth hole 100mm (3-15/16in)
Power-driven att. spindle speed Max. 8,000min-1
Power-driven att. drive motor 2.2kw
Coolant tank capability 170l
Dimensions (WxDxH) 2,334x1,200x1,695mm
Weight 2,600kg
Power consumption 4.7KVA

Backworking Attachment

Max. chucking diameter Ø 20 mm (25/32in)
Max. length for front ejection 80 mm (3-5/32in)
Max. parts projection length 30 mm (1-3/16in)
Back 8-spindle unit  
Number of tools 8 tools
Max. drilling capability Stationary tool Ø12mm (1/2in)
Non-guide bush type Ø6mm (15/64in)
Max. tapping capability Stationary tool M10xP1.5
Non-guide bush type M5xP0.8
Sub spindle indexing angle C-axis control
Sub spindle speed Max. 10,000min-1
Sub spindle motor Built-in motor drive 2.2kw (continuous)/3.7kw (10min/25%ED)