Chip breakers

[Hukshawn]

Show me your best...

This is getting annoying.


Here's my tool

 

[woodchucker]

I don't see a chip breaker on that.
This is an old style carbide that I don't use it's chipped. But it has a chip breaker ground in.

These two also have chip breakers ground in. They are there to cause the chip to roll up and break. Your tool looks like it has relief but not really a chip breaker.

 

[Hukshawn]

There's no chip breaker on mine. I'm looking for suggestions on how to grind one in that still leaves for tool cutting well. I had to hog down a lot of aluminum and the birds nests were plentiful...

 

[mikey]

Increase your feed rate. Quite often, taking too light a cut at too slow a speed will produce stringers. Aluminum does this anyway but feeding faster helps.

 

[Jimsehr]

Chip breakers help manage the mess when turning . I use them most of the time . But you have to be carefull when cutting threads . You can change the profile of the thread form if you are not carefull.
Jimsehr

 

[intjonmiller]

Increase your feed rate. Quite often, taking too light a cut at too slow a speed will produce stringers. Aluminum does this anyway but feeding faster helps.

I played with that this past weekend. I was tracking down some chatter, and I knew that a more aggressive cut can stop chatter in many situations. I had some play in the cross slide because the screw wasn't held tight enough to the handwheel and saddle. That resolved the worst of it, and allowed me to go for much deeper cuts than before. Still nothing more than about 0.040", but that's a vast improvement over what I had been doing. Anyway, I tried varying the depth of cut, spindle speed, and feed rate, and it was fascinating to watch the different chips produced from a broad radius bit (one that is so large it barely goes into the tool post with some mallet tapping, so it wasn't likely to blame for the chatter).

At 0.010" and the nearest sfpm rate my machine can do relative to the usual charts I was getting long spiral pasta noodle chips from my 940 bronze. Cool looking and manageable, but taking up a LOT of space relative to the tiny chips it made by increasing the depth of cut beyond 0.025". My next project should be out of aluminum, so I'm wanting to try the same thing with that same bit.

 

[Hukshawn]

Increase your feed rate. Quite often, taking too light a cut at too slow a speed will produce stringers. Aluminum does this anyway but feeding faster helps.

I couldn't feed any faster, I was taking .040"-.050" cuts and I was starting to stall. I honed the cutter a few times to keep it sharp.
It was actually the shallower cuts/slower cuts that kept the string bunched up into a mass, but it was going too slow for the amount of material I had to remove.
I was getting annoyed with being whipped in the face...

 

[4GSR]

I have a turning tool I use on my 9" South Bend lathe I ground up years ago and still use today.

Take a piece of HSS any size suggest 3/8 or larger, grind a chip breaker on top of the tool bit using a Dremel or air grinder. Use a 1/8" diameter rock to create the chip breaker. Grind it about .030" deep, it'll take you awhile but you'll get there. Make this chip breaker about 1/2" long. The chip breaker will have the shape near that on a negative rake turning insert. Once that's done, grind side relief on tool bit and the front clearance with about 10-15 degrees cut like a CNMG CCMT insert would have. Next, just kiss the corner of the cutter, no more than .015", to remove the sharp edge. Last hone the edges and you're ready to start hogging iron. I can take up to about .100" dept to the side cut with about .003-.005" feed on my 9" SBL with this bit cutting 4140HT. Finish is horrible, but that's fixed by running a finishing tool for the last few cuts to size. When done this will look similar to that in Woodchuckers post above. This is strictly a roughing tool.

Oh, I forgot to mention, when you grind the chip breaker, leave about .010-.015" flat between the chip breaker and the side of the cutter.

Ken

 

[Hukshawn]

Could you take a picture?

 

[pineyfolks]

Here are a few. I use a dremel tool with a diamond cutter. It makes it quick and easy.