CNC Machinist: If Machining a 2 Stroke Crank?

Discussion in 'Workshop Tips and Secrets / Tools' started by Armilite, Feb 4, 2019.

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  1. Feb 16, 2019 #61

    Armilite

    Armilite

    Armilite

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    Made in USA 5 Lb Head 1-5/8" Face Lead Hammer Vinyl Handle
    Brand New
    $28.84Buy It Now+$10.00 shipping

    eBay item number: 282698174438

    There is Lead Hammer molds, but aren't cheap, start out at $90+. Here is a Lead Hammer Mold Set, 6 Pound, Perfect For General Non-Marring Hammer Work, USA
    Brand New
    $209.95
    eBay item number: 232116945298
     

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  2. Feb 16, 2019 #62

    pictsidhe

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    Maybe 'phasing' is an example of incorrect English usage in the USA. It's pretty common...

    I do know how to zero the runout on a crank, but I'm really slow compared to a wrinkly old guy who does it for a living. I've never seen or heard of anyone using a lead hammer to do it. You have to smack the cranks pretty hard sometimes and lead is awful soft to last very long. You do need something softer than your crank, or you'll dent it.
     
  3. Feb 17, 2019 #63

    Armilite

    Armilite

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    =======================================

    Phasing, is talking about Aligning the Crank Wheels, Runout is talking about a Measurement of the PTO/MAG Shafts. Some People have a Secure Stand with a Box with just a Square Chunk 6' x 6" x 3" of Lead, and grab Crank by both ends and Slam Crank Wheel against the Lead Block. Easier to Cast 6" x 6" x 3" Lead blocks.

    A nice Crank Rebuild Video showing some Pro Tools. One exception, Never Use a Press or Bearing Tool on the MAG end without the Nut on.
    https://www.youtube.com/watch?v=_1T_1SzD2Og

    2-Stroke Crank Rebuild and True. Showing one the New Jigs out. Expensive, but 4-5 Crank rebuilds can Pay for it.
    https://www.youtube.com/watch?v=9h-AbRQLGgA

    Fastest crankshaft rebuild, balancing. Makes me laugh every time I watch it. Be interesting to see How True they are when he's done.
    https://www.youtube.com/watch?v=r8lCGTltAm4
     
  4. Feb 17, 2019 #64

    pictsidhe

    pictsidhe

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    I'm not confused because i don't know how to measure or true a crank, I'm confused because you are using incorrect terminology.

    If you're going to insist on 'phasing' cranks, at least use proper units. It's usually an angular measurement, though time is sometimes used.
     
  5. Feb 18, 2019 #65

    mcrae0104

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    Last edited: Feb 19, 2019
  6. Feb 19, 2019 #66

    proppastie

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    I think we understand what he means,...its a shame the manufacturer did not have timing marks to line up, it would make things so much easier.
     
  7. Feb 20, 2019 #67

    Armilite

    Armilite

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    Good Article on "RD400 Crank Rebuild Guide." I suggest you Copy and Paste this whole Article into MS WORD and Save as a PDF.
    http://www.rrracing.co.nz/crank/

    When the Crank Wheels are Out of Alignment, it is also called Out of Phase by Crank Rebuilders. Once the Crank Wheels are in Phase or Alignment if that makes it easier for you to understand, then the Runout of the (2) Shafts between Centers is Checked. The Crank Wheels and PTO/MAG Shafts are usually 99% One Piece. Those Shafts can also be Bent also. So when Crank is apart, mount each PTO & MAG Half between Centers and check Runout of the Shaft vs the Crankwheel. There is a lot of Poor Machining Tolerances in the World.

    The photo on the Left would be considered Severely Out of Phase or Alignment.
     

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  8. Feb 20, 2019 #68

    Armilite

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  9. Feb 20, 2019 #69

    Armilite

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    phase noun
    \ ˈfāz \
    Definition of phase (Entry 1 of 2)
    1: a particular appearance or state in a regularly recurring cycle of changes phases of the moon

    2a: a distinguishable part in a course, development, or cycle the early phases of her career

    b: an aspect or part (as of a problem) under consideration

    3: the point or stage in a period of uniform circular motion, harmonic motion, or the periodic changes of any magnitude varying according to a simple harmonic law to which the rotation, oscillation, or variation has advanced from its standard position or assumed instant of starting

    4: a homogeneous, physically distinct, and mechanically separable portion of matter present in a nonhomogeneous physicochemical system

    5: an individual or subgroup distinguishably different in appearance or behavior from the norm of the group to which it belongs
    also: the distinguishing peculiarity in phase

    : in a synchronized or correlated manner
     

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