As Pete( Miner) comments, it could be that the carbide tool is at the wrong height.
Again, I don't like carbide inserts but that is me.
The geometry of how an insert presents itself to work is far more important to get right than a simple high speed tool.
Usually a carbide insert has perhaps a 3 degree whereas a hss will be perhaps 5 or 10 degrees and the latter solid and not held with a simple screw and brittle( which you have discovered).
However, if your lathe is new, it may not have been carefully adjusted and that factor alone will snap carbides like carrots.
Frankly, if it was me, I'd head for a decent hss tool and set it at tool height by holding it with a bit of Stanley knife blade.
OK,it was decided to alter (!) another of my replies, locked it and this may not be high class engineering and acceptable to believers in the black arts but it works!
Consequently, you should remove all the gibs and whatever. and remove old oils, greases and whatever, reset the feel of your lathe to suit you- and you alone.
This is NOT the full answer- nor the only answer, but you should try it, make a note of what you have attempted, what you discovered and report the findings. If you don't, tell me which insert firm you are patronising and I will buy shares in it( sorry!)
