Most will break the chip if the feed rate is right (high enough). If you use a fine feed rate the swarf is thin and will bend rather than thick swarf which breaks. Try double the feed rate but half the depth of cut, this will remove the same amount of metal per rev but will hopefully break

Out of interest what sort of depth of cut and feed rates were you using? Turning or facing?

Edited By JasonB on 09/05/2016 18:44:00

…and don't use coolant. You want the swarf to get as hot as possible. The tool already has a chipbreaker, you just have to use it correctly, as JasonB suggests.

Look for a feed and speed calculator to get you in the right ballpark. If you have an Apple or Android phone, most of the main manufacturers provide them free. Why spend good money on something like this and then guess how (not) to use it?

I'd say the feedrates were too low for proper chip formation. I very rarely use less than 4 thou per rev for finishing and higher rates for roughing. Aluminium often seems to need on the order of 8-10 thou per rev to get proper chip breaking.

Personally I'd be running more like 1200 rpm for 1.25" steel, but that's partly because my lathe is **** noisy at top speed. To keep the metal removal rate up I increase DOC and feedrate. I never use coolant with insert tooling. You want the shear zone to be hot. In theory at least most of the heat generated ought to be in the chips rather than the work. The work can get too hot to touch, but steel chips come off straw or blue, and so are much hotter. If a chip goes down your shirt front it turns the air blue too!

Andrew

I remember when I was at Tech Collage in Dunedin in 1963, the school got a new Chipmaster and our teacher gave us a demo, don't know what steel he used, but a 3" bar, and a 1/2" depth of cut, and blue swarf for miles, you could have made bandsaw blades from it. Us kids were most impressed, and then we went back to the old Harrisons with the line shaft drive, and clicking belts.

Ian S C

Let me guess the answer to Martin 100's question:

If the metal being cut is heated enough, it becomes soft, and so (a) easier to cut) and (b) with less problems curling or chopping up the swarf.

I made a clutch disc (6.5" dia) from a circular saw blade on my Myford using a carbide insert, and the swarf came off red-hot. Slower speed produced juddering, etc.

Cheers, Tim