insert angle and long strings

[savarin]

Now I'm past the interrupted cut and turning down the continuous diameter I am getting really long straight blue strings.
The insert has a dip in the end that I assumed was the chip breaker except it doesnt.
Am I traversing too fast, slow, shallow, deep , wrong insert, whatever.
I dont like them and they are very sharp and dangerous.
How do I stop this?

 

[JimDawson]

Take a look at this thread. I was having the same problem

http://www.hobby-machinist.com/show...ew-trick-today?p=209806&viewfull=1#post209806

 

[Bill C.]

Now I'm past the interrupted cut and turning down the continuous diameter I am getting really long straight blue strings.
The insert has a dip in the end that I assumed was the chip breaker except it doesnt.
Am I traversing too fast, slow, shallow, deep , wrong insert, whatever.
I dont like them and they are very sharp and dangerous.
How do I stop this?

Try a lighter cut and a faster feed. I am not sure what your lathe is capable of doing. If you watch YouTube videos those inserts are used on heavy powered lathes.

Those strings are dangerous specially if they start wrapping around the work piece and grabbing more strings.

I prefer the cemented carbide. I can grind them in the shape I need including a groove to break the chips. Problem is after I get the bit ground and touched up several times the little remaining chip of carbide breaks off. Then I have to start all over.

 

[savarin]

weirder and weirder, started this morning and it cut just as I thought it should.
curled swarf.
Experimented with speed of feed and found a slower feed than I was using did the trick.
I then went to a faster feed and off they came as long straight strings.
Went for a deeper cut and again long straight strings.
Very low feed very shallow cut tiny curled threads that almost ignighted.
So I've sorted it out, just have to get the feed speed right and all is well.

 

[DMS]

I have found getting that getting good chips from a carbide insert takes a bit of experimentation, and has to do with feed rate, spindle speed and depth of cut. Typically I find that if the feed or depth of cut is too low, then I have issues with long stringy chips. I also find that kicking the speed up or down a bit will let you narrow in. It is also going to depend on the insert radius and the chipbreaker.