the mess of machining cast iron

Still easier than shearing stainless steel sheep. ;-)

The chip breaker grooves are one thing. A more extreme way is the way the Aloris BXA16N (and presumably both other sizes of that line, and other models of the direct insert holders from Aloris) work. They have a sliding clamp over the insert with provisions to move a carbide ramp (which is part of the clamp) to a fairly wide range of distances behind the cutting edge, so you can tune the chipbreaker part to your needs.

In the 16N, the groove in the inserts which I use is to produce effective positive rake in a negative rake holder.

Granted, I haven't turned 304 SS, and from what I've read about it, I don't really *want* to, so 304 SS may defeat even the tunable chipbreaker on the Aloris tuning.

Enjoy, DoN.

Slower rpm heavier cut. If your machine is strong enough. john

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Be reminded that fine cast iron dust/graphite is flamable/explosive. It is an ingredient in sparklers and fireworks. *FINE* cast iron dust/graphite in an explosive charge makes a much louder bang and a bright white flash, e. g. firecrackers, most likely due to the fuel/air effect. Grain dust/flour in air will also explode under the right conditions.

Not necessarily.

I learned about chip breakers turning a 7 inch piece of 304 about 3 feet long down to 5 inches. It was cutting pretty good and I cranked the spindle speed up a bit and it shot a light brown chip straight off the tool bit and right past the tail stock. It must have been 15 feet long by the time I got the lathe turned off. That damned chip must have been a quarter of an inch wide and about an eighth of an inch thick.

One of the other guys walked over and said "Maybe you might need a chip breaker there". and I said, "Show me how to grind one".

What do you think of this?

-jsw

I made a shifter knob for my old Mini when I was 16 out of a chunk of that crap.. The "rough cut" sure lived up to it's name and made the

10" south bend grunt. The finish cuts made gobs of wool. Don't know if I would want to do it on my Myford Super 7.

Nothing wrong with it but I never say anyone who worked in a shop use anything like that. In the Airforce shop we used to have the kids just starting out make a little sheet metal gauge with the various angles on it to check their tool bits but by the time they were a journeyman they didn't use it any more.

========================= you might like this

and this

FWIW a quick way to cut a groove type chipbreaker, even in carbide is with an air or electric die grinder (drimmel tool) using a cut off wheel. I have had good luck with these. Doesn't have to be a deep groove, just deep/wide enough to catch the tip of the chip as it curls to cause it to break off.

Works with both carbide and HS, although a little faster wer with HS

Yup, one shop had one. The Shop Chief was quite insisted that it was solely for grinding carbide.... which nobody used :-)

Yes, but I didn't understand the mention of a need for a follower rest (we called it).

Well, chip breakers aren't really a precision thing and they do vary in efficiency depending on speed and feed so we used to just grind a notch on the top of the tool, or a little flat to lower the cutting edge a bit and try it. If it worked, Wonderful! And if it didn't than make another visit to the pedestal grinder :-)

good safety tip- never though about the stuff burning up, although it should be pretty obvious as given enough surface area steal/iron will burn (steel wool).

Gunner Asch fired this volley in news: snipped-for-privacy@4ax.com:

It needs LOTS of oxidizer. With gobs of barium nitrate (which is a good one), iron dust barely burns. THAT is what sparklers are made of.

Cast iron dust doesn't become pyrophoric until it's down below 1/4- micron, and then only if it's deliberately cast into the air.

There are some 'toasted' mixtures of coarser iron powder and sulfur that are more pyrophoric -- enough that they reliably burn when cast into the air.

But, then, sulfur is a very effective oxidizer for iron.

The rest of that post was silliness. Iron is about useless in flash powders, and mixtures of iron and oxidizers won't explode without extreme measures to contain them.

Iron has never been used to increase the power of an explosion or to make a white flash. That's aluminum... Iron makes branching yellow sparks.

LLoyd

Fine dust in the right concentration in air is adequate. See the cited videos. Remember that a fair fraction of cast iron dust is graphite, in effect coal dust, which is highly explosive, and if this flashes, it can be enough to ignite the iron dust. See how it sets the shirt on fire in the video.

Years ago CI dust build up was a problem in line shaft drive machine shops. When I worked at Carter Carburetor in the mid 60s, there was still a area with line shaft drive machining cast iron, the WCFB cast iron four bore flange line. About every 6 months or so, when everybody had forgotten about the last fire and let housekeeping slide [place was like a coal mine], there would be a fire along the overhead shafts, with star bursts when it got to the spinning pulleys with the larger dust build up and better air flow. No serious injuries as I recall, just some superficial burns from the falling "sparkles," but several people were hurt running for the door or the line motor switch.

Remember that a fair fraction of cast

Carbon can be Diamond, Graphite , or amorphous . Diamond is not easy to bu rn. I have heated diamond when speltering a bit for trueing grinding wheel s and it did no burn. Graphite in any reasonable sized pieces is also hard to ignite. In fine dust it maybe close to acting like amorphous carbon, b ut I have used graphite as a base for silver soldering without it burning.

Fine dust is something else. Next time I machine some cast iron , I will p ut some of the chips on a fire brick and see how hard it is to ignite.

Dan

Gunner Asch fired this volley in news: snipped-for-privacy@4ax.com:

Heh! Yeah... designing such formulae and the machinery to manufacture stuff from them what I do for my business!

LLoyd

Sucking the stuff up with a vacuum cleaner would be more likely to cause trouble than sweeping the stuff up.

I've got a pile of cast iron dust I can experiment with now.

Gunner Asch fired this volley in news: snipped-for-privacy@4ax.com:

Yeah... well, SOMETIMES it's fun. Sometimes it's cool. The rest of the time, it's spending your time figuring out how to automate something and still meet all the codes and regulations controlling how you CAN'T have electrical machinery in explosives environments. (worse when Mil specs must be met)

Actually, that's simple, too, if you have an unlimited budget. My clients usually don't, and I SURE don't! So we have to 'figure a way' to satisfy the inspectors, and it's different every time we put together a machine.

It's still fun burning up stuff for a living. I'd have done it for free in my youth, if someone had let me.

Lloyd