[deadlykitten]

hy gunda

tricky moments

i recomand :
... mrWizard's tip
... torque skip when 2nd chuck clamps the part + logging/writing clamp position to file + checking it to be within safe limits
... using load monitor along entire W travel
... clamping the part at low rpm, and after that raising the rpm and begin cutting

depending on setup length, how long will it be there ( hours - days - weeks, etc ), you may decide what to do :
... a longer setup is justified for using more safeties, because stuff may happen during the long run
... a shorter setup may only require operator surveillance, because adding extra code requires too much time
* in time, if you build parametric custom safe code, you may configure it fast also for short setups

Do you think backing off slightly as OkumaWiz advises is beneficial?

of course mr Wizard had been in this bussines for long, and he know what he is saiyng

imagine that you clamp inside the 1st chuck a piece of plastic ( something softer ), and you start to cut it : all should be ok, the part will fall, etc

now pls imagine that you also push it with the tailstock, with huge pressure : when the cutting tool will be close to center ( but not yet at center ), the part may get moved by the tailstock, and it may end up like in image 01; because is plastic, nothing will happen

now replace plastic with metal : as a result, tailstock live center may get damage, tool insert & tool shank may get damage

all these happened because the part was tensioned, it was compressed

the 2nd chuck may actually compress the part :
... if compression is big, part will fly off during cutting ( this is rare )
... if compression is low, it may shorten the insert life, because it will be pushed sideways; in this case :
...... if insert life is long enough, it is possible to ignore this phenomen ( this is why few people use this technique )
...... if insert life is short, or if you have been arround cnc machines for long time, then you may notice this phenomen

one more thing : if you keep a record of insert life spam, and parts / edge, you may notice that insert life is longer when cutting without tailstock, or without a 2nd chuck this is easy to say, but in reality it really requires time to gather all this data

I've done part transfers many times on swiss type lathe machines but using just a straightforward approach has worked for me so far

ookey, i would like to say that, even if things work, this does not mean that there is no problem : there are problems with spontaneous effect, and problems with effect manifested among long time

swiss lathes generally use collets, and the collet has the tendency ( during clamping ) to drag the part inside, into it, while a jaw chuck has the tendency ( during clamping ) to spit the part out; as a result :
... a part clamped between 2 chucks has a big chance to be compressed
... a part clamped between 2 collets has a big chance to be stretched
... when you open a collete, the part may shift towards, or fly out at speed, like a mini-bullet
... when you open a chuck, the part may shift inwards

there are special chucks that try to drag the part towards them when closing, so to achieve higher repetability and minimeze the tendency to spit the part out

on a swiss i had experienced an uneven wear on the cutting insert ( image 2 ) : if i inspected the insert with a magnifier, i could see that one corner was dulled very much, while the other corner was ok; the difference was hard to notify ... even so, the insert would last for more then 8 hours, and parts would seem acceptable ... in the end i solve it ( reduced tool hangout, thicker insert, etc )

What do you actually try to show in the code example in your last comment?

the method presented by mr Wizard requires a bit of set-up time, that needs to be done in manual mode; that code is doing just that, thus it is adjusting the loads in automaticall mode, so there is no longer need to adjust the setup in manual mode ... it saves a bit of time / kindly