An 800's Rebirth/The build of MechanicO

Discussion in 'Parallel Universe' started by FinTec, Dec 12, 2014.

  1. FinTec

    FinTec Been here awhile

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    This is where I wanted to tackle the infamous (more than famous, it is IN-famous) rear shock mount bend-a-thon. Yea, this does seem to be a pretty bad design on BMW's part. By not supporting the mount bolt directly on each side of the shock eye-let you negate all the benefits of a true clevis system. Why they did this, who knows. But while I have this apart, it is fixing time.

    So sure enough when I took the bolt out it was very bent. And this was after using a Tractive/Touratech rear shock with a hydraulic hard-stop. Now I was expecting the bolt to be bent but when I put one of my machinist squares on the tube strut that the shock mounts to I could see a substantial bend in the tube. Pic:

    [​IMG]

    Not super clear in this pic but you can just see gaps on each side of the square. Now, in defense of BMW I did do some significant jumping, fully loaded......repeatedly. And I do remember bottoming out the rear.......repeatedly. So not too surprised here, but still crazy to see.

    Shot of the area without new mount

    [​IMG]

    Need to machine a new clevis mount to weld onto above tube. Took a piece of 1018 (mild) steel I had and planed it down to height

    [​IMG]
    [​IMG]

    Then hole drill to match the diameter of the frame

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    Bolt hole

    [​IMG]

    After this I just took the part and finished the profile my hand on the bandsaw, sanded down smooth and then the dry fit here.

    [​IMG]

    The stock spacer now needed to be lathed down shorter

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    While here welded up the riv-nut that was there

    [​IMG]

    And tig welded the new clevis side onto frame

    [​IMG]

    Mach-ed it all up and looks great. That bolt will not bend baby!

    [​IMG]

    But now we need to make sure that cross tube does not bend anymore.....
    dirtriderdan, waylongway and Shooby like this.
  2. FinTec

    FinTec Been here awhile

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    Now to double down and make sure the frame tube does not bend anymore because I plan to jump MechanicO like a he was trying out for a Dukes of Hazard episode. Yehaaaa!

    So I made this "bar" from some mild steel and out a bunch of mount holes in it because I also planned to use this for mounting/supporting other items down the road

    [​IMG]

    Test fitting before welding

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    [​IMG]

    Aaaaand welded in place

    [​IMG]

    That tube should be a rock now and not move. I figure I bend that, something has gone very wrong.

    Then a quick fit test to make sure not in way of custom air-box and good to go.


    [​IMG]
  3. Indy Unlimited

    Indy Unlimited Long timer

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    Great job at the shock mount Fin!
    That is the way BMW should have built our frames.
    likes this.
  4. Shane007

    Shane007 Adventurer

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    Man, I wish I had access to $100,000 worth of machining tools and equipment. That's some stellar work bro! Can't wait to see it all back together again.
  5. Buschog

    Buschog Long timer

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    I wish I had the skill to use the equipment
    njoytheride and zivi123 like this.
  6. 2WheelTraveler

    2WheelTraveler backinthesaddleagain Supporter

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    I wish for a lot of things, but I am a realist about my capabilities. Which is why I enjoy reading about those that have the talent and know how to use the equipment.
    There is something to be said for also having the vision to create something so special.
  7. Shane007

    Shane007 Adventurer

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    For sure. I've done a little CNC work and it's really intriguing to me. I think that getting to Fin's level of precision and quality of work would take YEARS of practice and training. I love watching this masterpiece come together.
    njoytheride likes this.
  8. FinTec

    FinTec Been here awhile

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    Thanks for kind compliments guys. Hey, machining really is not that hard and I was never trained for it to be honest. Just turned from hobby to part of my job. But it is like golf, you will never master it. I still break drill and end mills!

    I do some "open days" here at my shop here in Colorado. For example, in a few weeks I am hosting a "makers" night where in two hours we will make brass bottle openers for everyone that attends. We'll do this using both the cnc lathe and mill. Just a taster really of a machine shop.

    But what I emphasize STRONGLY at these events is: learn to computer model. The act of 3D modeling has some similarities to machining. You are working with base materials and features. It is NOT like the old days of vector 2D lines in AutoCAD. And the really good news is these programs are very powerful and very inexpensive now. The one that is getting some serious traction and attention is Fusion 360 (from AutoDesk). It is a full featured CAD and CAM program that runs from the cloud. Hundreds of tutorials and support forums as well. And not expensive at all. Looks like it is $300/year but I see they are having a sale right now for $99! But there is also a free trail version.

    Bottom line, if you can model it, you can probably make it. But if you get the modelling skills down, you can at least make the choice to either have some them make it for you or look at figuring out how you would make it. Starts with a model.
    gearsoup, anth13, Shooby and 5 others like this.
  9. vesteroid

    vesteroid Adventurer

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    Mind pointing to some of the best tutorials for f360?
  10. FinTec

    FinTec Been here awhile

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    vesteroid,

    I have not looked at the tutorials for Fusion 360 as I actually use another program of Autodesk called "Inventor". But did a search on YouTube and got these results:

    https://www.youtube.com/results?search_query=fusion+360

    What I suggest is stick to videos that only show you how to model and not spend time on the CAM part. Plenty to learn on just modeling. Be interested to hear if you use it and what the cost came to for you?
  11. vesteroid

    vesteroid Adventurer

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    I bought it during the sale and have done a few tutorials and have a basic working knowlege of cad from the sign industry. I use sketchup at a mid to high level and use specifc software to operate routers so I know enough to be dangerous. I was on the fence about getting a mill lathe combo but kept holding off knowing that with no cnc making the kinds of things I wanted to make would be difficult and time consuming. Your post here just confirms that to me. Color me jealous of your equipment. I would say I have been welding a bit longer than you have, but your machining makes me look like a total newb.

    great work and I will keep learning fusion.
  12. FinTec

    FinTec Been here awhile

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    vesteroid,

    Excellent! I have only dabbled in F360 as some other friends have gotten into it. The price is amazing for the power you get. Share something you modeled when you get a chance.

    Yea, getting one of those multi-mill_lathe units has some drawbacks. They are excellent for basic fabricating but fall short on the kind of parts I want to make. As you have figured out as well. Good news is CNC controlled machines are cheaper and easier to find now. I have seen Fadal CNC centers like mine going for under $10k now. Amazing price for what you get. Full function, full capacity cnc milling. And now I am seeing bench top CNC mills with amazing power. That said, I do love my manual machines though for the quick and fast cuts.

    Yep, far better machinist than welder! I always figured I could make a crappy weld and then machine it down to look good :lol3

    But the good news is F360 is the 1st step. If you can model it, you can machine it later or send file to someone who can.
  13. wipe-out

    wipe-out Been here awhile

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    Hint hint[​IMG]
  14. gearsoup

    gearsoup Adventurer

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    Hmm?
  15. 2WheelTraveler

    2WheelTraveler backinthesaddleagain Supporter

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  16. 2WheelTraveler

    2WheelTraveler backinthesaddleagain Supporter

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    The suspense is building.
  17. FinTec

    FinTec Been here awhile

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    Gaaa, sorry guys, life took off on me. Have all the pics of the last build stage done just have to get off my ass and post. And bugging me works!
    waylongway likes this.
  18. FinTec

    FinTec Been here awhile

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    Another items I am adding to the mix of "save the rear shock support" is to install a stiffer rear spring. I originally speced the rear shock with a 160 kn spring and, as brought up before, I would bottom this out now and then. The guys at Touratech where very helpfull and we decided to just up it one to the 170 kn spring.

    However, the Touratech guy was a little too helpful. He warned me that they no longer offer that same shock with the adjustable height clevis on the bottom. Apparently the lock-nut would strip the aluminum threads on the clevis over time. So sure enough I went out and tried to pull the lock-nut off and it would just spin. Bummer. I really liked the adjustable height option, So I had an idea....

    Here is the clevis from the bottom of the rear shock with the Lock-Nut still attached.

    [​IMG]

    Had to take a dremel and split the nut to see for myself the damage.

    [​IMG]
    [​IMG]

    Yep, the threaded are jacked. The design flaw here is that when you jam to nuts together (in this case a lock nut and the lower threaded assembly) you load the lower lock nut in the downward direction. In other words, the threads on the lock nut take all the load. When those stripped, the threaded section of the shock took the load but that was a huge amount of thread engagmen and they did fine.

    So wanting to keep the adjustable height function I did this:
    I ordered a new clevis and two new lock nuts

    The idea here is to first use two lock-nuts to increase the thread engagement. Then using spacers take up the rest of the gap below the lock-nuts to the face of the clevis. This way, everything is stacked as a solid and the lock-nuts have no where to go. However, it did require the spacers be precise so the rebound adjuster faced outward,

    So I lathed up three spacers in 1mm increments. It is 1mm as the threads on the clevis are 1mm pitch so to get one full turn on the lower section of the shock and have the rebound adjuster face outward. Below are three spacer I made for this (the missing 1.5mm is installed)

    [​IMG]
    [​IMG]

    Now I still have height adjust but a bomb-proof set-up.
  19. FinTec

    FinTec Been here awhile

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    And to remove and install a new rear spring I had to make a collar for my press that let me get to the clip that holds the "hat" on the top of the shock so the spring can be exchanged.

    [​IMG]
    [​IMG]
    [​IMG]

    Still "concerning" when you have that much energy stored up. You want to make sure the whole thing does not squirt out the side of the press while trying to deal with it. Taking the time to make the right tools is always worth it.
    Buschog likes this.
  20. Indy Unlimited

    Indy Unlimited Long timer

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    Great work. I got the same rear shock. I guess I know what the fix is. I have not adjusted mine. Hope is stays put. Will keep an eye on the adjustor.