Seibu SFG-28HP
Image: seibudenki.com, Seibu
Key Specifications
Max Spindle
Spindle Power
chuck size
x axis travel
z axis travel
rapid traverse xz
How much does the Seibu SFG-28HP cost?
Price estimate
We do not have a price for the Seibu SFG-28HP that we can stand behind, so we show no number. Configuration, options and installation move the final price a long way: a quote is the reliable figure.
Overview
The Seibu SFG-28HP is the small machine of the SFG series, with a 4 inch standard chuck and X and Z travels of 300 mm (11.8 in) and 180 mm (7.1 in). Like the 6 inch SFG-35HP it is built to cut and grind inside and outside diameters in one chucking, and it carries the HP resolution: a 0.01 µm minimum setting unit and 0.01 µm scales on X and Z.
Against the SFG-35HP, everything around the spindle is one size down. The through hole is Φ20 mm (0.8 in), where the SFG-35HP has Φ32 mm (1.3 in). The AC spindle motor is rated 1.5/2.2 kW on a continuous/15 minute rating, where the SFG-35HP lists 2.2/3.7 kW on a continuous/30 minute rating. Top speed is the same 3,000 min-1, so the smaller machine brings no extra surface speed for small diameters.
What does not shrink much is the machine itself. It weighs 2,200 kg (4,850 lb) including the control board and measures 1,684 × 1,870 × 1,776 mm (66.3 × 73.6 × 69.9 in). The spindle centre is 1,100 mm (43.3 in) from the floor, rapid traverse is 4,000 mm/min (157.5 ipm) on X and Z, and the tank is 270 or 370 L (option).
One caution on capacity. Seibu's page prints two different length figures for this model's maximum gripping work size, one in the heading and one in the table. Confirm the gripping diameter and length with Seibu against the actual part. The C axis is position control only unless the synchronous control option is ordered.
Full Specifications
| Parameter | Value |
|---|---|
| Chuck Size | 4 inch |
| X Axis Travel | 300 mm (11.8 in) |
| Z Axis Travel | 180 mm (7.1 in) |
| Rapid Traverse Xz | 4,000 mm/min (157.5 ipm) |
| Minimum Setting Unit | 0.01 µm (X axis is diameter) |
| Scale Xz | 0.01 µm |
| Center Height Above Cross Saddle | 105 mm (4.1 in) |
| Max Spindle Speed | 3,000 min-1 |
| Spindle Bore | Φ20 mm (0.8 in) |
| Spindle Drive | Built-in |
| Spindle Motor Power | AC spindle motor 1.5/2.2 kW (2.0/3.0 hp) (continuous/15 minute rating) |
| Spindle C Axis | Position control only (synchronous control is an option) |
| Spindle Center Height From Floor | 1,100 mm (43.3 in) |
| Machine Dimensions | 1,684 × 1,870 × 1,776 mm (66.3 × 73.6 × 69.9 in) |
| Machine Weight | 2,200 kg (4,850 lb) including control board |
| Tank Capacity | 270 or 370 L (option) |
Specifications sourced from seibudenki.com — verified 2026-10-05
Strengths & Limitations
Strengths
- 0.01 µm minimum setting unit and 0.01 µm X and Z scales on a 4 inch chuck machine
- Cuts and grinds inside and outside diameters in one chucking
- 300 mm (11.8 in) X travel and 180 mm (7.1 in) Z travel
- Built-in spindle to 3,000 min-1
- Lightest SFG model at 2,200 kg (4,850 lb) including the control board
Limitations
- Spindle through hole is Φ20 mm (0.8 in); the SFG-35HP has Φ32 mm (1.3 in)
- Motor is 1.5/2.2 kW on a continuous/15 minute rating, the smallest in the series
- Seibu's page is inconsistent about the maximum gripping length for this model
- Synchronous C-axis control is an option
Best For
Frequently Asked Questions
01
It is the 4 inch chuck machine; the SFG-35HP has a 6 inch chuck. Travels are 300 mm (11.8 in) and 180 mm (7.1 in) against 350 mm (13.8 in) and 220 mm (8.7 in) on the SFG-35HP. The through hole is Φ20 mm (0.8 in) and the motor 1.5/2.2 kW. Both share the 0.01 µm setting unit and 3,000 min-1.
02
The minimum setting unit is 0.01 µm, with the X axis set as diameter, and the X and Z scales are listed at 0.01 µm. Those are the same figures as on the larger SFG-35HP; the SFG-35P is the model set in 0.1 µm.
03
The main motor is an AC spindle motor of 1.5/2.2 kW on a continuous/15 minute rating. It drives a built-in spindle with a maximum speed of 3,000 min-1 and a Φ20 mm (0.8 in) through hole.
04
The standard chuck is 4 inch. Seibu's product page gives two different length figures for the maximum gripping work size of this model, one in the heading above the table and one inside it, and notes that the size varies with workpiece shape, weight and cutting tool interference. Ask Seibu for the figure that applies.
05
The machine dimensions are 1,684 × 1,870 × 1,776 mm (66.3 × 73.6 × 69.9 in) and the weight is 2,200 kg (4,850 lb) including the control board. The tank is 270 or 370 L (option), and the spindle centre is 1,100 mm (43.3 in) above the floor.
