View Full Version : What material might this be?

07-13-2007, 10:41 AM
Anyone recognize these characteristics?

4" round, very fine scale/rust layer; chucked it in the lathe at 700 rpm (too lazy to change speed right then) carbide insert tool and just wanted to clean the surface off so maybe .003 DOC?

The surface came off in a blizzard of -tiny- chips. Blue ones.
I was going to change the speed but was caught up by the fact that the surface was very bright.
Try another pass, this time extremely fine, long blue corkscrew threads came off. I mean FINE. And thin.
Again, the surface was very bright.

Then I tried HSS and the surface went hazy.

I know, could be a thousand different things and this is like saying "my car is making a noise" but just wondered if that rings a bell for anyone?

07-13-2007, 10:48 AM
Sounds to me like some sort of metal.

Rusty Marlin
07-13-2007, 11:00 AM
Sounds to me like some sort of metal.

Oh come now Even you cn do better that that... He did tell us it was rusty.

So some sort of Ferrous based metal is much more accurate..... It might even have some carbon in it.

07-13-2007, 11:00 AM
.....You're Canadian, aren't you.


07-13-2007, 11:02 AM
And the other one's from Virginia.
That's the South's one guess for the year then , eh?


Rusty Marlin
07-13-2007, 11:32 AM
lets start here.


As the HSS tool didn't intintiously melt off, I'd say something VERY low carbon with a lot of sulfur and/or lead. That narrows it down a bunch. BTW turn your RPMs down if you plan on tool life. 225 to 250 SFM for Carbide and 70 for HSS for low carbon free machining steel.

If you had continued to get powdery chips I would say some form of grey cast iron.

If it had been a peice of 4140, the tip of your HSS tool would have burned off in the first rev in brilliant red/orange sparks.

07-13-2007, 11:37 AM
Just a guess, but I'm thinking maybe case hardened or heat treated high carbon steel. You say you got tiny blue chips with a shiny surface for you first two cuts, then a hazy finish on the third? Sounds like you cut through a "case" into harder material below, especially when you say you did the first two with carbides and the last with HSS. Sounds like the same thing I saw when I used a combine shaft to make a jackshaft for a project...:rolleyes:

Then again, it would be interesting to see what was left of the HSS at that cutting speed.

07-13-2007, 03:57 PM
blizzard of -tiny- chips. Blue ones.

12L14 , I would bet on it.

07-13-2007, 04:18 PM
Oh come now Even you cn do better that that... He did tell us it was rusty.
Want to see my stash of rusty aluminum? It was stored in a bin outside with steel. Looks like rusty steel until you pick it up. I even put some through the electrolytic deruster. It worked.

I turn 1040 medium carbon steel at 150 sfm with HSS Dormer bits as a matter of course. Lots of smoke and very blue chips. Makes a nice finish.

Sounds like semi-steel or durabar.

Rusty Marlin
07-13-2007, 11:47 PM
Even, how is your tool life at that SFM? I was taught that if the chips are blue off HSS that its running too fast. Gold's OK but blue is bad. I notice that when I get blue chips I get a built up edge rather quickly and then starts the rubbing and the heat softens the cutting edge and... poof gone, no more cutting edge.

It obviously works for you... who is Dormer? and what do they put in thier brand of HSS that makes is so heat resistant?

07-14-2007, 12:25 AM
12L14 are 1215 take a .050 face cut at 600 rpm with carbide and tell us what happens Better yet a picture

07-14-2007, 01:25 AM
I don't use carbide much. Too much trouble to sharpen although I do have the equipment. Dormer is a branch of Sandvik AB. As far as I am concerned they make the best cutting tools, bar none. Others may be equal but none are better. You pay accordingly, of course. A single 3/8 x 16 tap will cost nearly as much as an entire Chinese set. It will also tap 100 times more holes and will not break.


Tool life is good. I sharpen my own so it isn't a big deal to throw a few licks on the tool with a diamond hone now and then. I do a lot of things that aren't by the book concerning lathe tools.

Here's a pic of my South Bend doing exactly what I claim. You can see the work diameter is about two inches and the drive belt is on the middle cone. That gives 325 rpm approx which gives about 160 SFM.


07-14-2007, 01:59 AM
Evan, that looks like London fog to me........or is that cigarette smoke?:D

07-14-2007, 06:28 AM
I smoke a pipe. That however is essence d' mineral huile. I believe the 'secret' ingredient in the Dormer HSS tool steel is cobalt. Good for improving red hardness.

Cobalt High Speed Steel

This high speed steel contains cobalt for increased hot hardness. The composition of HSCo is a good combination of toughness and hardness. It has good machinability and good wear resistance, which makes it usable for drills, taps, milling cutters and reamers.


07-14-2007, 11:25 PM
Turned the speed down...not much difference except no long stringers and less blue chips.
Note I said "less" as the shop and I are lousy with chips.
In my hair, in my beard, down my pants, in my shoes. The dog.
It'd be a great chunk of material for what I want (new mount for the cross slide) but this is ridiculous.
Metal Supermarket Monday for something more machinable.