70Y CNC Mill-Turn Machine – 1,000 to 3,000 mm Cutting Length with a Mohs 5# Tailstock
The 70Y is the long-bed option in the BONANZA mill-turn range. Most machines in the catalogue are built around one fixed bed length, but the 70Y is offered with cutting lengths from 1,000 mm to 3,000 mm, so the platform can be sized to the shaft work you run.
The published sheet covers the 1,000 mm version: 720 mm turning diameter over the bed, 480 mm cutting diameter, an A2-8 spindle with an 85 mm bore and a 37 kW motor, on an 8,000 kg frame.
The 70Y at a glance
| Parameter | 70Y (1,000 mm build) |
|---|---|
| Max. turning diameter on bed | 720 mm |
| Max. cutting diameter | 480 mm |
| Max. cutting length | 1,000 mm (range 1,000 to 3,000 mm) |
| Spindle nose type | A2-8 |
| Spindle bore diameter | 85 mm |
| Spindle motor power | 37 kW |
| Spindle speed (as listed) | 3,000 rpm |
| X-axis travel | 300 mm |
| Z-axis travel | 1,020 mm |
| Y-axis travel | ±75 mm |
| Rapid traverse X / Y / Z | 12 / 12 / 16 m/min |
| Tool turret | 12-station live tool turret |
| Machine dimensions | 3,950 x 2,160 x 2,485 mm |
| Machine weight | 8,000 kg |
The cutting length range is the point of this model
Most of the mill-turn line is quoted at one bed length. The TCK3100LY is a 1,000 mm machine, the TCK6050SY is 450 mm, and the HTMC machines run 1,200 to 1,500 mm. The 70Y instead covers 1,000 mm to 3,000 mm in one family, so a shop turning 1,200 mm rolls and 2,500 mm cylinder rods stays on the same spindle, turret and control package.
The numbers above are tied to the 1,000 mm build. A 3,000 mm machine carries a longer bed, different Z travel and a heavier casting, so those figures will not apply. Ask for the sheet for the exact bed length you are quoting.
Why the Mohs 5# spindle structure tailstock matters
On a long part, the tailstock decides the accuracy more often than the spindle does. A shaft supported at one end whips, and flex at the free end shows up in the finished diameter. BONANZA builds the 70Y tailstock with a No. 5 Morse taper quill on a spindle-type structure rather than a simple sliding sleeve, for better rigidity at the top and a longer service life.
A sleeve-type quill loses alignment as it extends and wears, so the centre drifts and the operator compensates by tweaking the setup. A quill riding in a spindle-like bearing arrangement keeps the taper concentric through the stroke and holds that alignment as it wears, which is the difference between a diameter that holds and one that drifts across a shift. The No. 5 Morse taper takes standard live centres and drill chucks without adaptors, so tailstock tooling is easy to source.
37 kW on an A2-8 spindle with an 85 mm bore
The spindle nose is A2-8 with an 85 mm bore, driven by a 37 kW motor, which is a lot of power for a machine of this class. For scale, the TCK3100LY runs the same A2-8, 85 mm bore spindle with no motor rating published, and the TCK6050SY is an 18.5 kW machine on a smaller A2-6 nose with a 67 mm bore. The 37 kW figure tells you BONANZA expects this machine to take serious depth of cut in steel and stainless.
The sheet lists one spindle speed, 3,000 rpm, under a heading that reads “spindle speed range”. Treat that as a maximum until the factory confirms otherwise. A 37 kW, 85 mm bore spindle usually carries a gearbox or a wound-field range, and the low-end torque decides whether you can run a 40 mm insert drill. Get the full speed and torque curve with the quotation.
Interpolation Y axis and a 12-station live tool turret
Y travel is ±75 mm and the turret is a 12-station live tool type. Real Y travel lets an end mill cut a flat or a keyway off-centre without a second setup, which is what separates a mill-turn machine from a lathe with driven tools bolted on. The 2100LY takes the idea further with the turret mounted directly on the pallet and a low cutting centre of gravity, rated for 7 to 10 mm single-side cuts.
Travel is 300 mm on X and 1,020 mm on Z against a 1,000 mm cutting length, with rapids of 12, 12 and 16 m/min. X travel of 300 mm is tight for a machine that swings 720 mm, so check that your largest boring bar clears before committing to a process, and confirm the usable X envelope at the 480 mm cutting diameter.
Where the 70Y sits in the mill-turn range
The CNC mill-turn series runs from sub-500 mm shaft machines up to the 240 mm bore QK1322, and the family overlaps enough that the model number alone will not tell you which one fits.
| Model | Cutting dia. / length | Spindle | Y travel | Weight |
|---|---|---|---|---|
| TCK6050SY | 400 mm / 450 mm | Dual: A2-6 (67 mm) + A2-5 (56 mm), 18.5 kW | ±50 mm | – |
| TCK3100LY | 500 mm / 1,000 mm | A2-8, 85 mm bore, 75 mm bar | ±100 mm | 8,000 kg |
| 70Y | 480 mm / 1,000 to 3,000 mm | A2-8, 85 mm bore, 37 kW | ±75 mm | 8,000 kg (1,000 mm build) |
| HTMC500T | 500 mm / 1,250 mm | A2-8, 86 mm bore, 75 mm bar | ±125 mm | 14,000 kg |
| HTMC800T | 600 mm / 1,500 mm | A2-6 or A2-8 | ±125 mm | – |
| TCK2300B | 400 mm / 500 mm | 400 nose, 65 mm bore, 50 mm bar | ±60 mm | – |
The 70Y and the TCK3100LY share the same 8,000 kg frame and the same A2-8, 85 mm spindle, but the 70Y trades Y travel for bed length and a much larger motor. Short work that needs maximum Y-axis milling goes to the TCK3100LY; long work that needs heavy stock removal goes to the 70Y. When the part is big in both directions, the HTMC500T and HTMC800T jump to 14,000 kg and ±125 mm of Y.
Who the 70Y suits
- Long shaft and roll work between 1,000 mm and 3,000 mm that needs turning, milling, drilling and threading in one clamping
- Heavy stock removal in steel, stainless and alloy bar up to 85 mm through the spindle bore
What to confirm before you order
The sheet covers the 1,000 mm build and stops there. Ask for these with the quotation:
- Specification sheet for the bed length you need, since travel, weight and footprint change across the 1,000 to 3,000 mm range
- Full spindle speed and torque curve, and confirmation of what the listed 3,000 rpm represents
- Maximum bar capacity, which is not published even though the bore is 85 mm
- Number of live tool stations, driven tool power and speed, and whether a sub-spindle or bar feeder interface is available
- Positioning and repeat positioning accuracy, and the acceptance test standard behind them
- Usable X envelope at the 480 mm cutting diameter, given the 300 mm X travel
- Total connected power and the foundation drawing
Frequently asked questions
What is the maximum cutting length of the 70Y?
1,000 mm on the standard build, with the family offered up to 3,000 mm. The table above is for the 1,000 mm version.
What is a Mohs 5# tailstock?
A tailstock with a No. 5 Morse taper quill on a spindle-type structure rather than a plain sliding sleeve. The spindle arrangement keeps the quill rigid and concentric through its stroke and wears more slowly, which helps hold accuracy on long shafts.
Is the 70Y a true Y-axis machine?
Yes. It has ±75 mm of Y travel and a 12-station live tool turret, so it mills flats, keyways and off-centre features in the same clamping as the turning. If you need more Y travel, the TCK3100LY offers ±100 mm and the HTMC machines ±125 mm.
Bottom line
The 70Y is the machine in the BONANZA mill-turn range built for length: 1,000 mm to 3,000 mm of cutting length around an A2-8, 85 mm bore spindle with 37 kW, real Y-axis travel and a Mohs 5# spindle structure tailstock. If you turn long shafts that need milling in the same setup, price it against the TCK3100LY for short, wide-Y work and the HTMC500T if the parts are both long and heavy. Send the BONANZA team your drawing, material and batch size, and you will get a straight answer on which one to put on the floor.