Sub spindle usage

After 18 months of searching for a replacement for my QT15 that went out with a bang I've finally found something in my budget, a SQT18MS. The used market in the UK for Mazaks in the sub £20k area is all but non existent and I have plans to retire in 4 yrs time so throwing £40k at a machine just wouldn't make sense so I've ended up with this sub spindle machine. I've never used a sub spindle before, is the b-axis soley used to "pick" off from the main spindle and then homed to use the turret z-axis for turning? Is it common to use the sub-spindle as a 2nd lathe if you wanted to run two different parts on one machine? I'm thinking more of if I wanted to leave a long running job on the main spindle and use the sub for some small jobs in between.

Depending on how small your job is, the sub might be too limited.
You can only have about 4" of stickup with a drill or boring bar before they'll hit the housing when the turret rotates.

They're also a lot weaker in HP and overall rigidity than your main spindle.

The B axis can also be used for holding a spring loaded live centre and using it as a tail stock. It works surprisingly well.

Leaving the main set up for one job, and using the sub for everyday work is definitely possible.
Though I think you'd gain a lot more time doing everyday work on the main, just because its so much simpler for setup and programming.

ManualEd said:

The B axis can also be used for holding a spring loaded live centre and using it as a tail stock. It works surprisingly well.

Click to expand...

Is there any additional info on using this method? Also have a subspindle but would definetly prefer classical tailstock to use it for shaft work.