[Newbie] Speeds and feeds - stringy chips.

[Ben17484]

I’ve got some mystery steel that won’t break a chip and gives me huge birds nexts and really long strings that eventually wrap around the work or chuck.

I’m using insert tooling (tried two different tools) and have tried a combination of speeds (360, 560, 800) with feeds (0.044mm, 0.087mm, .218mm) and with and without oil. I’ve tried different depths of cut (0.1mm, 0.5mm, 0.75mm). Nothing seems to work and break up the stringy chips.

Any advice on things to try?


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[tq60]

Pecking, just stop feeding for a second, that stops cutting.

If auto feeding just disengage the 1/2 nuts and engage again.

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[OTmachine]

Trial and error to determine feeds, speeds, and depth of cut for mystery metal. employ or adjust chip breaker.
You could look here: https://archive.org/details/machiningdatahan0002unse/page/n1/mode/2up

 

[rwdenney]

A deeper cut or a bigger bite will break chips better, but if that isn’t an option, releasing the clutch every couple of seconds will break the strings.

Rick “worst for me with 1018” Denney

 

[benmychree]

Set speed for 100 FPM plus, set cut deep as possible, use coarser feeds until chips break.

 

[TIM-RANEY]

I would echo comments above...stop the cut periodically to break the chip. When this kind of thing happens to me, that's usually what I do. If the finish suffers a bit, I make a final shallow cut or two usually <0.005". Though it depends on the workpiece's function in whatever I am making.