1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.
  2. PLEASE: Read the FORUM RULES BEFORE registering!

    Dismiss Notice

Metal unknown?

Discussion in 'ATLAS, CRAFTSMAN & AA' started by fast204, Apr 12, 2017.

  1. fast204

    fast204 United States Iron Registered Member

    Likes Received:
    1
    Trophy Points:
    3
    City:
    hillsboro
    State:
    New Hampshire

    -Return to Top-

    So let me first say, Thank you to all those that have provided some insight and experience to getting my hand me down lathe up and operating. As of now I have made a few pins for my tractor, a couple of axels for my pit bike and various parts and pieces for a couple gun builds I'm well into.
    I was given a 5gal bucket of some misc metal over this last weekend and it has me scratching my head.... I separated it into what I could best tell. There is a few small rounds of aluminum, a few very nice pieces of brass hex stock, some misc larger hex stock and a lot of 1.5" - 2.0" rounds of material unknown. It is steel of some grade, covered in rust from sitting in a water saturated bucket.

    I cleaned up a piece the unknown and wanted to make a few practice passes on the lathe. What I got was chatter, terrible surface finish and frustration. I am using hand ground HSS. I thought it must be the tool so I chucked a piece of material, 304ss. I was able to take a .030" doc advancing freehand with the carriage and got a very respectable finish. I then took a cut on a piece of 1018 and aluminum 6061 just to make sure I was not fighting an improperly ground tool as this is something I'm new at. I decided to try with my carbide inserts and was unable to cut either the 304ss or the mystery steel?? Am I missing something or are the clearance angles on the hand ground HSS allowing me to cut the stainless but not this mystery material?

    Any thoughts are welcome.
     
  2. ghostdncr

    ghostdncr United States Active Member Active Member

    Likes Received:
    78
    Trophy Points:
    28
    City:
    Louisville
    State:
    Kentucky

    -Return to Top-

    I don't know of any way to positively identify "mystery metal" but there are a couple of tests I do on the (frequent) occasions I run across some. You may already be familiar with these tests, but I'll post it it just on the chance it proves helpful. Foremost, you say it's rusted so we should be able to conclude it's some grade of either iron or steel.

    I start out by addressing an edge of the material with a good file. If I get a good, sticky cut with a decent output of shavings, it's safe to call it unhardened. Steel will produce slivers, whereas iron filing tend to be more like a powder. Pre-hardened materials (like 4140, P20, etc.) will resist the file, require considerably more pressure and produce far fewer shavings per cut, but the file will cut them. Full-hard steels like heat treated A2, D2, H13, or even Thomson shafting, will have nothing to do with a file, squealing at the file stroke and producing no shavings.

    The third test I'll do is touching the material in question to a grinding wheel. Different materials produce different spark patterns when ground and by comparing the shower of sparks to any number of charts illustrating these patterns, a fairly close identification can usually be determined. https://en.wikipedia.org/wiki/Spark_testing

    I've usually been able to get pretty close to accurate identification using these methods and once the material is ID'd, it's much easier to develop a machining strategy that will produce accurate cuts and a good surface finish.
     
    scwhite, ch2co, British Steel and 2 others like this.
  3. Silverbullet

    Silverbullet Active Member Active Member

    Likes Received:
    445
    Trophy Points:
    83
    City:
    Marlton
    State:
    New Jersey

    -Return to Top-

    The steel if hardened sometimes can be annealed to a point that machining is possible. About forty years ago I ordered a piece of 4140 steel in a three inch square x 8' long. When it arrived at the shop it had been flame cut from a large plate. Guess what no tool in the shop would touch it , hard it was super hard. So we sent it back to the seller he sent it to a treating plant and annealed it. We made hold downs for our open sided hydraulic planer. I turned the pins on one end to fit the table , machined the squares to size , then I set them up on a thirty degree angle drilled and tapped on the angle , 3/4 - 16 . Using drill rod fully threaded turned long taper points to lock down the work to the table. Turned out to work so well our boss paid me to make a dozen total in my home shop at the time. My old Sheldon and m head mill worked great made those and lots more in a little one car garage back in 1976. Still have a couple small pieces of the steel in my shop now. Made jacks for using on the planer and VBM. Out of them.
     
    scwhite, ch2co and cathead like this.
  4. fast204

    fast204 United States Iron Registered Member

    Likes Received:
    1
    Trophy Points:
    3
    City:
    hillsboro
    State:
    New Hampshire

    -Return to Top-

    I have not had a ton of time to re visit this metal as work has picked up quite a bit but I did run a file across it the night I got your post and the cut produced shavings and not actual chips. leaning more towards iron of some grade?
     

Share This Page