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Thread: Bullneck frame machining

  1. #21
    Join Date
    Apr 2008
    Location
    Upper Yarra Valley, Victoria. Australia
    Posts
    829

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    Thanks William and Larry.

    Customer had a go at removing the stiffener.

    P9060001_5.jpg

    I spent a couple more minutes with a cold chisel and a 2 lb hammer and removed the pieces obstructing the hole.
    I needed to do this so I could get the boring bar through.

    P9060003_4.jpg

    P9060004_3.jpg

    P9070001.jpg

    P9070002.jpg

    My inside mic reads that I still have a thou and a half to cut out.

    You know your close when the skin of the metal is so thin it peels up behind the tip and exposes the original bore.
    I will finish this bore off and move to the next fixture. You may have seen in one of the previous pictures that the customer has welded up a missing piece of the trans support. I will have to machine it and drill the hole.
    Steve Little
    Upper Yarra Valley. Victoria.
    Australia.
    AMCA member 1950

  2. #22
    Join Date
    Apr 2008
    Location
    Upper Yarra Valley, Victoria. Australia
    Posts
    829

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    Next fixture clocked to the machine.

    P9070005.jpg

    Tightened the forging into the fixture.
    While looking up at my digital readout, I wound the table across to the measurement to drill the hole.
    When I looked down to see where the center drill was pointing I thought Whoaa!! What have I done wrong!

    P9070006.jpg

    Did a quick re-check of the measurement and it turns out the customer's attempt and re-creating the missing piece with a welder, was a little over exuberant.
    Drilled the center drill to the appropriate depth and followed it with a 3/8” drill.
    Used a 7/8 end mill to recreate the spot face for a washer to sit against.
    Then licked the hole with a chamfer tool to take the sharp edge off the hole. The customer can remove the unwanted extra length.

    Interesting side note.
    That circular mark between the 2 strengthening ribs, is the original witness mark of HD's hold down clamp of their machining fixture.
    The machinist has most likely passed on, but we see your signature old mate


    P9070007.jpg
    Last edited by Steve Little; 09-07-2017 at 01:07 AM.
    Steve Little
    Upper Yarra Valley. Victoria.
    Australia.
    AMCA member 1950

  3. #23
    Join Date
    Apr 2008
    Location
    Upper Yarra Valley, Victoria. Australia
    Posts
    829

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    Hmm This is the fixture for the next operation but the rear engine mount isn't going to fit with the brake cross over tube, still in place.
    I remember designing this fixture years ago, and those 2 pinch bolt posts were held in place with cap head bolts from underneath.
    The young guy who used to drive the cnc machine must have added some welds for greater rigidity.

    P9070008.jpg

    Compared to a traditional mill, a cnc machine is blistering fast. But the increased speeds and feeds, create big loads on the fixtures.
    If a fixture breaks and a spindle crash ensues, the repair bill can easily get into $10,000 or $20,000 in seconds.
    Strength and rigidity are the standard catch cry for any experienced machinist who makes fixtures.

    A well placed slice through the front weld and four or five measured whollops with the 2 lb hammer and it folded over and left the scene at speed.

    P9070010.jpg

    After fitting the forging and tightening it down for action, I fitted a 7/8 end mill and did a couple of cuts to clean up the welded deck. It took 0.020 to remove a twist from the accident and also level out the uneven welding of the deck.

    P9070011.jpg
    More gooda??

    The exuberant deck fixing looks stranger from this side.


    P9070012.jpg
    Steve Little
    Upper Yarra Valley. Victoria.
    Australia.
    AMCA member 1950

  4. #24
    Join Date
    Oct 2013
    Location
    Maryland
    Posts
    217

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    Man, this stuff is GREAT!

    Dale

  5. #25
    Join Date
    Feb 2011
    Posts
    192

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    labour of love ,some hours have gone into it so far

  6. #26
    Join Date
    Apr 2008
    Location
    Upper Yarra Valley, Victoria. Australia
    Posts
    829

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    Hi Dale and Rob. Glad the info has appeal.
    A couple of friends like to get in my ear and reproach me for keeping 30 years of Harley frame restoration locked up in this leaky mind.
    One buddy in particular likes to knuckle my brow about getting the information into print before it evaporates completely, but I don't think I have a hide thick enough for that.

    These rear engine mount decks are surprisingly weak and are easily bent. When I used to restore frames it was my first port of call for things to check.

    P9070013.jpg

    P9070015.jpg

    This deck was no different. I brought the end mill down to touch the left hand side and locked it. Then wound the table across to see how the right side registered. That is a 030” feeler gauge between the tool and the deck.

    P9070017.jpg

    We cant have that sort of shenanigans. It took ;033" thou to clean it up.
    The brake cross over tube was also slightly bent during the accident. The customer will rectify that.

    P9070018.jpg

    Rear engine mount ready for service again. Next forging will be the front engine mount.
    Steve Little
    Upper Yarra Valley. Victoria.
    Australia.
    AMCA member 1950

  7. #27

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    Good to see you on board .
    I always enjoy all post . Keep it up.Very helpfull.

  8. #28
    Join Date
    Mar 2009
    Posts
    539

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    Very interesting to follow along. Thanks, Steve!

  9. #29
    Join Date
    Apr 2008
    Location
    Upper Yarra Valley, Victoria. Australia
    Posts
    829

    Default

    Thanks Dan and Rooster.

    Front engine mount took a beating as well. The side stand and clutch bracket are bolted to the left side and they must have come in contact with something. There's a pretty noticeable bend on the left side of the engine mount. Threads on both sides are no good and would strip if tensioned up. I will have to get advice from customer if he want me to address that issue. Anyway. On with the pictures.

    P9070019.jpg

    Instead of using the 100 ton press (red one in background) I thought I would see how the little 10 ton (orange) press would do the job.
    This would give a backyarder an idea of how easy it is to straighten a bent forging.

    P9080008.jpg

    I'm proud of the little 10 tonner. It straightened it relatively easy. No bunch of grapes hanging out the back.
    I did a bit of a pressing with the support blocks set wide apart.

    P9080009.jpg

    After a bit of press work and further assessment, I brought the support blocks in closer. The following shot shows the part still under pressure. After releasing the pressure, it didn't need any further persuasion.

    P9080011.jpg

    Set up one of the machining jigs for this picture and set it on the mill table. This allowed me to see how square I got the face in relation to the engine mount holes. I'm happy with that.

    P9080013.jpg
    Steve Little
    Upper Yarra Valley. Victoria.
    Australia.
    AMCA member 1950

  10. #30
    Join Date
    Apr 2008
    Location
    Upper Yarra Valley, Victoria. Australia
    Posts
    829

    Default

    See if the forum limit for a days posting is up.

    While the engine mount was in this fixture, I decided to cut the top engine mount pads to take out distortion.
    This is one of the cnc fixtures and made for multiple engine mounts. One by its self in the center kind of looks forlorn.

    P9080015.jpg

    0:020 needed to come off the pads to achieve a flat surface.

    P9080016.jpg

    P9080017.jpg

    All done. Onto the next forging. The rear axle needs its mates.
    Steve Little
    Upper Yarra Valley. Victoria.
    Australia.
    AMCA member 1950

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