Long stringy chips while boring

[BobM3]

I'm trying to bore out a 3.5" ID steel tube. I'm having a tough time with the stringy chips getting wedged between the part and the tool. I'm using diamond shaped carbide inserts with built in chip breakers but they aren't breaking the chips. Any ideas out there for breaking the chips?

 

[mrainey]

Higher feedrates break chips better, as does application of lots of properly-aimed coolant.

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[BillPSU]

Just as mrainey said, higher feedrates break chips better. You can also change material increasing the carbon content say from 1018 to 1027 making the material slightly harder improving the chip breaking. You can also experiment with different chip breaker designs if you can get a salesman to get you the samples. You can also reduce the size of the inserts as smaller inserts have smaller chip breakers but you will need different boring tools.

 

[kagan]

Check your contact angle. I mean check your tool and insert for being positive or negative. Also try CXXX type insert

 

[ornerynorsk]

Steel tubing and pipe will always produce long stringy chips. Higher feedrates will only make it difficult to hold size unless you have a VERY rigid setup. I have found that a heavier cut with a slower feedrate gives you excellent accuracy and beautiful surface finishes. You still have the stringy chips, but you just need to pull them out as they are cut.

 

[meltaylor3]

"mechanical advantage over velocity ratio" I.E.Drop the speed and put up the feed plus plenty of coolant, also, use
triangular tip boring bar with 04 tool nose radius. For roughing you want 0.25mm feed, leaving between 1mm or0.5mm
in bore for finishing

 

[limba]

We use a DNMG insert with a 08 or 04 radius. This insert gives us more clearance between the bar and the material than a TNMG style. Depending on length of overhang of bar try depth of cut of .015-.030 inch. We also blow compressed air along the bar sometimes to help get chips out.(Works best in through holes)