To be posted by JWR on

Discussion in 'General Discussion' started by dragonfly, Feb 28, 2009.

  1. dragonfly

    dragonfly Monkey+++

    Something I wrote, in answer to questions re: machining and tools for the job.

    (Personally, it has been my experience that no one, unless you are a "hobbyist", should ever use one of these machines.
    They are fine for very small parts only, and parts made of either plastics, brass, or aluminum.
    Why? They cut really fast, easily, and require no specialized tooling.
    No extreme pressures, but, the speeds are up there, about 1,200-1,800 rpm.
    It all comes down to ONE word: Rigidity!
    If it isn't solid, you have wasted time, money and energy.
    You cannot get gold, from junk.

    1) A lathe was made to "turn" 'rounds', period.
    You can dress them up with a number of additions/accessories, to make a lot of items not easily made by the lathe itself. (BUT, everything you do, costs more money!)

    2) Mills are what they are, and anyone that has ever operated one, knows what's their most important feature/factor.
    Not just weight, but the rigidity of the entire unit, from the "quill" to the bed, to the knee, (if it's that type of mill).
    You cannot do much with a small lightweight machine, it's like trying to mill on a drill press!
    (It just Won't work!)
    Like I said above, those smaller combination units may work ok, but not for any serious metal turning or milling, especially of steels.
    It is comparable to soldering-versus-MIG or TIG welding!
    You have to have the right machine for the correct operation.

    I own a "very well used" 1939 circa metal lathe, belt driven, 9-12" swing, and 32" length material capacity. Geared head and has a range of 12 speeds.
    It still, holds within .002"-.005" accuracy, and I've never "adjusted" it so far.
    It weighs in at 400+lbs. With the small 3/4 horse 115 volt ac motor, it can make anything I want it to.
    It only cost me $800.00 !
    (with that being said, 1 collet chuck cost me $600.00 alone! Then there were the collet sets and such, as well as the repacement 3 and 4 jaw chucks that ran around $280.00 each) Not cheap to get into, and not for just anyone! IF you don't know what you are doing, in this area, get some help! (MOST mistakes are quite costly!)
    BTW: they can, and they do, tear people up, if you make "1" single mistake! (The boss' wife lost her hair, all off the top! Now she has to wear a custom wig!)
    Stay away from a lot of imported stuff, UNLESS you know it's a real "brand name" that you can easily get parts and tooling for .

    A machinist friend of mine bought a "Jet" lathe a few years back, then discovered it was smaller than what he thought...It had a swing of only 3 1/2 " and a material capacity of 11 3/4 ".
    He paid over $600.00 for it, and it only weighed about 45-47lbs!
    It was great, "IF" you were making model aircraft or train components...
    He has it sitting on his desk, as it's only 18" long, and makes an interesting paperweight! (conversation piece?)

    Look for the stability, and "serviceability" of the tools you select for the "proper" job.
    In other words don't use a chisel in place of a screwdriver, and vice-versa!
    There are quite a few OLDER models out there today, and...not all Chinese made tools are that bad either. ( he says, tongue-in-cheek!)

    For example, a mill I used a lot in aerospace mfg, was an old "MaxMill", a big old "boat-anchor", that just wouldn't quit. The writing on it's electric motor was in Chinese, and I never did know much about it! We also had an "X-Cello". (I have no clue!) But it was a good solid machine!
    For "our" lathes, nearly all were made in China, as the really older ones made in Japan were decrepit/deceased by then.

    My personal favorite was the "WEBB" or "Takisawa" (same same), the guys in the shop called it the "widow maker"...It was a broken detent, that allowed it to drop into crossfeed mode, at it's own whim. Once it was repaired, I'd have paid $5,000.00 for that old junker! (cost to repair: $.10).
    Note: Most of the OLDER DOD requirements, mandated that any part made for them or by use in any military equipment, had to be made on a machine built/based in the United States only!
    That meant out of OUR shops 6 mills, we could only use 3 of them,(Bridgeport's) and of our lathes we could only use 1, the "Hardinge". (nice toy if you have the $$$).
    That included all manual mills lathes and all cnc machines.
    We had machines from Germany, Holland, China,and Japan.

    Today, thousands of these older 'dinosaurs', are on the market...
    You can get an older "Southbend Lathe", for a song and a dance, and with all the tooling!
    You'll need a lot of guys and maybe a forklift to move it though!
    Bridegports are the same way!
    Stay away from all of the CNC's, UNLESS you know programming!
    In the machining business, you have to figure it this way: "Weight is equal to quality and accuracy"!)
    Bill in Phoenix
  2. Seacowboys

    Seacowboys Senior Member Founding Member

    We nave Bridgeport CNC, a big lathe, and a serious press at the shop in Creola but our machinist died and haven't replaced him. I can manage turning pretty well and a lot of milling operations (manual) but I get lost when it comes to cutting threads.
  3. krock

    krock Monkey++

    we use all bridgeports at my shop.they never break.the lathes we have are old and jacked up.
    i did cnc mill and lathe for awhile and apprenticed in tool making in my 20's on the old school stuff.i moved on to sheetmetal and mostly run cnc and mechanical brakes now.
    there are auction houses and used machine places out there where you can get stuff really cheap,but some of the old stuff is worth it's weight in gold.we're looking for a roller now and can't find a decent one under 20 grand.
    you guys ever run a laser or waterjet?i'm still in awe of those things,ours will cut 6inch thick steel.
  4. dragonfly

    dragonfly Monkey+++

    Not me, I saw them in use at another shop and was amazed!
    They were cutting a heavy 1 inch thick black stone that was oval shaped, for Harley Davidson belt buckles! Dan hall was the guy with that contract! The lasers were used to cut 3/16 sheets of specialized steel into "hammers" for some firearm...
    I polished them after they were "sliced"...what a clean cut! Faster than any millwork I'd everseen!
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