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Mystery (to me) Metal

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MattM

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#1
Picked up a 1.5" round of something out of my scrap box to make an adapter. Turned at about 950RPM with carbide. Absolutely beautiful finish taking small cuts. However, the swarf looked like semi-coarse steel wool and would sometimes spark and actually glow and catch to flame. Next operation was to drill a through hole. Easily done: two steps and a reamer to 7/16" ( the 0ther side will be 3/4"). So far no problem...

Now to the bandsaw. Would scratch but not cut. Maybe a dull blade? No, replaced it not long ago. Took it out and tried it with a hand saw. No cut. Then tried a file, scratched it.

Why would this metal turn and drill easily and seem to be hard when sawed.
 

JimDawson

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#2
Something case hardened or hard chromed. Hydraulic cylinder rods and heavy equipment pivot pins would examples.
 

MattM

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#3
Not hard chrome and not a hydraulic cylinder. Certainly did not look case hardened.

Just for kicks I went out after dinner and sawed off a piece of known 12L14. Cut like a knife through soft butter. Chucked it and turned it with the same tool at the same speed . Nice chips but finish was not nearly as perfect. No sparks, no fire and no "steel wool".
 

JimDawson

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#4
Or maybe just surface hardened 4xxx material. Truck axle or something maybe?
 

rgray

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#5
Titanium makes swarf like that. Posible??? Likes to burn also.
 

MattM

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#6
Or maybe just surface hardened 4xxx material. Truck axle or something maybe?
That could well be. I do have some axle material. But why would it turn and drill easily but not take to the saw?

Definitely not Ti.
 

JimDawson

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#7
But why would it turn and drill easily but not take to the saw?
I have some material like that (machinery pivot pin). It is pretty soft in the center, but hard on the OD. I can saw it, but requires the slowest speed of the saw and a bi-metal cobalt blade, high feed rate to maintain cutting.
 

pontiac428

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#8
What does a spark test tell you? Is it magnetic? Does it work harden? Can it be annealed?
 

MattM

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#9
It is magnetic. I'm no spark expert but seems to spark like 1018. Anyway not a big deal. I made the part out of 12L14. No problem.
 

randyjaco

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#10
Does it happen to appear to be aluminum or ferris?
 

P. Waller

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#11
I often part off ball screw stock with carbide inserted parting tooling, case hardened about .050" below the minor thread diameter, this operation is not in the least bit nice but beats the band saw, $150.00 saw blades VS $10.00 inserts, do not try this at home.
 

T Bredehoft

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#14
Why would this metal turn and drill easily and seem to be hard when sawed.
Drill because the center was soft.

It did not turn easily, you were using carbide, and got a very fine hard shaving. If you'd had HSS it would have blurred over.
 
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#15
Don't think it's magnesium if the chips start the fire the whole chip pan burns. Or at least what one of my machinist I worked for told me. We had a job turning some at his home shop , I worked for him part time while in vokie . A start up company then Microcircuit Engineering . I machined the castings for the screen printing . After two years it was a boring under paid job to say the least , but Jim did teach me some things for sure. Shame he died young , to much stress.
 
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