Gary at EE ground a chip breaker on the tool used in one of his videos. Try asking him for details or just experiment.

You could use a cut off wheel in a dremel type tool to grind a groove a couple of mm back from the cutting edge, or perhaps make some form of chip breaker from a bit of bent steel.

Neil

Tangential tools are inherently prone to continuous ribbon swarf because the cut material flows away relatively freely. The flip side of lower turning forces and good finish from the clean cut.

Chip breakers work by imposing a sharp bend on the ribbon swarf as it flows across the tool causing it to fracture. Cooling of the hot chip adds to the stress making fracture more likely.

The geometry of a tangentila tool makes it harder to generate a really sharp bend to promote fracture. On conventional flat tools a semi-circular (ish) groove immediately behind the cutting edge is a common way to a mke a chip breaker. Wasteful of tool steel as the whole groove has to be periodically ground away after a few sharpenings otherwise the tool has to be thinned down to the base of the groove.

An alternative, but not quite as effective is to put a sharp step close behind the cutting edge. Less wasteful of tool steel as the top remains at the full tool steel depth and the step can simply be moved back on resharpening. Especially if you don't use back rake along the length of the tool. For the depths of cut normal with smaller hobby lathes I'm skeptical of the value of such rake anyway.

A step is pretty easy to add to a tangential tool and is not wasteful of material.

Clamping an extra piece of thinnish steel above a conventional flat tool gives much the same chip breaker effect as a ground in step. Most economical on tool steel but you cannot use back rake and there is a risk the the chips could get under the separate piece, particularly so if the tool projection is significant. Although simple and pretty effective it's not a very common method, mostly due to the perceived risk of things going awry. Generally not suitable for common tangential type holders. Often old style top clamp carbide holders were arranged so the clamp acted like a chip breaker of this form. Easily done with the simple flat, usually triangular inserts that were common many years ago.

Clive

A bit difficult to add a chip breaker plate to the top of an Eccentric Engineering  tangential cutter. Grinding a groove behind the cutting edge could work but would have to be done each time after re-sharpening. (easy, quick sharpening with the supplied jig is an advantage with these cutters)

Carbide inserts for the lathe are available with and without a chip breaker. Those without can use a bolt-on chip breaker as shown in this Youtube video. **LINK**

Also a lot of different QCTP holders, demonstrated by Joe Pieczynski

Paul

Edited By Paul Lousick on 25/02/2022 06:38:03

As Hopper says chip breakers are primarily for breaking up thicker swarf. On industrial size lathes taking industrial size cuts the thick birds-nest effect can be very dangerous. Thick, stiff razor sharp random coils take a deal of unwinding.

If you do put a simple chip breaker on a tangential tool it just goes straight down as you re-grind so its not wateful. Needs a steady hand to keep it in the same place tho'. I imagine one of the thin angle grinder cut off wheels would do the deed nicely but I'd want a jig.

Adding a step needs a proper jig to put the narrow faces in front of it on.

I suspect that you still won't get nice chips. Snail shell roll seems more likely. Something I often get with a parting tool. Such rolls periodically break off when they become too large. I suspect that on most of our size jobs the roll will break at the end of the chip rather than becoming large enough to break mid cut.

Clive

Although tidying up long ribbons is a pain I'd rather not have chips! Run hard and fast with carbide insets my lathe produces them in an unpleasant smoking hot spray. Whilst the metal removal rate is impressive and chips don't cause tangles, ribbons are more civilised.

At my work rates a commercial HSS cutter with a built-in chip-breaker rarely produces chips. I'm sure it would work if I cut more aggressively but doing so calls for flood cooling which I avoid because of the mess.

Dave