Haas ST-15

The Haas ST-15 puts a bigger spindle on a small lathe. It has an 8.3 in (210 mm) chuck, a 3.5 in (88.9 mm) spindle bore and 2.5 in (64 mm) of bar capacity, with the 16 in (406 mm) Z travel and 7.88 in (200 mm) X travel of the ST-10. Spindle power is 20 hp (14.9 kW) with a 4,000 rpm top speed.

Set against the ST-10, everything about the spindle is a size up. The ST-10 has a 6.5 in (165 mm) chuck, an A2-5 nose, a 2.31 in (58.7 mm) bore, 1.75 in (44 mm) of bar capacity and 75 ft-lbf (102 N·m) at 1,300 rpm. The ST-15 has an A2-6 nose and 150 ft-lbf (203 N·m) at 500 rpm, twice the torque at well under half the speed. What it gives back is rpm: the ST-10 reaches 6,000 rpm.

That shapes the work. With 2.5 in bar and peak torque at 500 rpm the ST-15 is at home in steel bar and in chucked blanks of moderate diameter, where the ST-10 would be short of torque. On small brass or aluminium parts the 4,000 rpm ceiling is the constraint.

The envelope depends on the turret. Maximum turning diameter is 12 in (305 mm), 11 in (279 mm) with a BMT45 turret and 6.8 in (173 mm) with a VDI turret; swing is 16.5 in (419 mm). The turret row reads 12-station BOT, with 0.75 in (19.1 mm) of rear clearance for boring bars. Rapids are 1,200 ipm (30.5 m/min) and thrust is 3,300 lbf (14,679 N) on each axis.

The table also lists sub-spindle and tailstock figures. One detail is specific to this spindle size: the sub-spindle is rated 6,000 rpm and synchronises up to 4,800 rpm, both above the main spindle's 4,000 rpm, so on a hand-off the main spindle is the slower partner. Confirm with Haas what the quoted machine has. It ships at 7,900 lb (3,584 kg), and the starting price Haas lists is US$70,995.