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Thread: Another Gingery Metal Lathe

  1. #11
    @ kcoffield I melt aluminum from castings. I think most of this is from a machine from
    South Korea. No idea what grade it is. @ Tobho Mott, I have an infrared pyrometers, but
    not very good with controlling the temperature of my furnace yet. Still as fast as I am
    able to pour the aluminum starts to freeze before I finish pouring the melt. I'll have to
    work on that

  2. #12
    I just recently reconditioned my sand. I built a muller. I also checked the ordering information recently. It says my sand is natural red sand, I didn't believe this; being in China. I used the muller more for crushing the sand. My sand box got flooded last spring, rained all summer. A few weeks ago I completely dried it, crushed it in the muller, then reconstituted water into it. I added the water with a spray bottle in my sand box. Turned it over with a trowel, then put it into plastic buckets. I ran it through my riddle a couple of times to airate it. It seems fine now.
    Last edited by Alex Webster; 09-24-2017 at 04:49 PM. Reason: Formatting

  3. #13
    Yesterday I put shims under the carriage saddle. Currently less than .03 mm ( 0.0011 inches ) play up and down. Will need to take more off to try
    to get that lower. Started scraping the front of the bed ways, as near as I can tell this is off by .15 mm ( 0.006 inches ). The book for this lathe says
    minor imperfections are ok, but it still binds moving up and down the ways. I still have a lot of work to do. What qualifies as minor errors?

    lathe_assembly1.jpg

    lathe_ass2.jpg

  4. #14
    Find out where its binding. If you loosen the clamps just a little, and keep the gib tight, then see if it binds when moving up and down the ways. If so then its the front and back of the ways that arent parallel.
    If its ok, then reverse it, loosen the gib just a little and keep the clamps tight. If it binds when moving then the ways top and bottom surface arent parallel. Cold rolled ways like that are known to warp several thousandths from parallel. Strategic shimming between the ways and bed could attempt to straighten it.

  5. #15
    Thanks FrostOak. I finished scraping the bed ways today. A small amount of play but not measurable with my 0.04 mm ( 0.0015 inch ) feeler gauge.
    I snugged the gib screws with a screw driver, no torque applied and I can slide the saddle up and down the ways. No significant binding and the gib
    screws won't need to be that tight. I'm happy with it. Now to scrape the cross slide.

  6. #16
    With the saddle and bed ways finished, yesterday I square the cross slide ways and installed the front screws.

    squaringcs_ways.jpg

    cs_ways+screws.jpg

    I also put the brake screw in the back of the saddle. I'm using a hex screw for now, it holds the saddle from sliding
    on the ways when finger tight.

    saddle_back_screws.jpg

    There it sits on the coffee table. I love my wife for this.

    lathe_ass3.jpg

    It's actually starting to look a bit like a lathe.

    Next to do:

    cut and install clamps to hold the cross slide on the cross slide ways
    insert the jib, 2 screws this time
    line up, drill and tap holes for the cross slide lead screw
    fit the swivel base and ways for the compound slide

  7. #17
    Sorry about the delays. I ran out of propane and in this local area I live, sometimes is hard to get.
    I decided to recast the carriage saddle and cross slide due to some erroneous drilling I did. I also
    re did my flasks such that I can use the methods described by sandrammer on YouTube.

    I've been careful to keep my temperature below 750 degrees Celsius. I also think I need to melt ingots
    first then use them to cast parts with.

    Overall I was impressed, not with my casting, but with the technique applied following sandrammer.
    This piece leaves a lot to be desired for sure. However the cut was just 2 mm from the sprue and no
    crap in the part. No oxide or dirt, clean. There is dirt and some bubbles formed on the surface
    of the part which I think is from gas from in the alloys I'm melting.

    saddle_new.jpg

    The aluminum alloy used for this was from some piece of pre cast, from something made in South Korea.
    IMHO this is still much better than the first casting I did last spring.

  8. #18
    Today was one of my weirdest in the shop. Temperatures lately sub zero at night and a but warmer in the day.
    At about 10:00 this morning temperature was about 3 degrees so I decided to do some casting in the afternoon.
    I cast alloy from an aluminum rim I had cut.

    I had just gotten this tank filled and I noticed as I was getting to melting temperature that my gauges were both near zero.
    I was thinking this would be another bad day, checked all my safety equipment. Fire extinguisher location, etc. As the heat in
    the furnace was still glowing and I expected to be running out of fuel, still watched the melt getting hotter. I'm hoping someone
    with more experience can advise me on this it seemed real strange. My tanks appeared to be dropping pressure, my infrared
    temperature sensor was being no help. I checked the steel rod I use for adding aluminum, dipped it into the melt and from this I
    was sure the temperature was correct so I poured.

    The mold filled up and I was able to make a few ingots as well.

    pour_Nov23.jpg

    The sprue is the small dot in the lower right, the other two bigger spots are from the risers. It actually filled faster than I usually get.
    Before using the methods described by sandrammer, I'd be lucky if the mold even filled up. I used a tin can to raise the sprue like the
    way myfordboy does. It still looks sloppy on the surface, gas and sand trapped in gas, but again much better than the first pours I did.

    crossfeed_new.jpg

  9. #19
    Senior Member Tobho Mott's Avatar
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    You can't go too far wrong imitating Sandrammer's methods...

    Keep at it, thanks for the update!

    Jeff
    Tobho had learned to work Valyrian steel at the forges of Qohor as a boy. Only a man who knew the spells could take old weapons and forge them anew.

    How I built my oil furnace | My Photo Album | My Videos | TheHomeFoundry Forums

  10. #20
    Senior Member
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    Alex,
    I don't think you have gas problems because the cross section looks very clean, no signs of porosity.
    I think that's sand wash. Maybe ram the sand more, check the moisture content and the fit of the cope to drag.
    Keep at it, every piece is a learning experience and if something isn't right, alter the process for the next piece. It looks like you're at the point that a couple small details will dial you in.
    Nice work!
    Bones

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