Case boring on my CNC

Discussion in 'Projects/Builds' started by fatcaaat, Aug 9, 2018.

  1. fatcaaat

    fatcaaat Well-Known Member

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    Well, I'm about a decade late to having this capability, but I finally do. I purchased a midsized chinese milling machine, added precision doublenutted ballscrews, and stepper motors on all axis and built myself a CNC machine. My first project out of the gate was to do a simple boring of a set of cases.

    Well, it turned out to be not as simple because I didn't have enough height to use my boring tool. I guess that would have been too easy, so I instead just chucked up a 3/8" endmill, programmed the circle, and gave it a pass. Perfect.

    I say that it actually took less time to do the setup, program it, and run the program that it would have taken me to die grind it. And the mess is completely contained! The results speak for themselves. Perfect!
     

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  3. Deoodles

    Deoodles Active Member

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    What a cool new to you toy.
     
  4. Tripod

    Tripod Member

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  5. kirrbby

    kirrbby Well-Known Member

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    That's awesome Fatcaaat.
    I'm still trying to figure out how you build minibike engines that are soo fast, and you've moved on to building the machines that are needed, to make minibike engines, go soo fast.

    Very nice.
     
  6. Tripod

    Tripod Member

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    Are you going to bore/overbore cylinders too?
     
  7. fatcaaat

    fatcaaat Well-Known Member

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    Definitely would not use an endmill for boring cylinders. I'll have to use the boring tool which will have plenty of space on the z axis to bore cylinders. I do need to perform a test or two to see how precise it performs. I imagine that cylinders will bore well, but I do need to try them. I may offer to do case boring and cylinder boring at some point for people, but I'm not ready to do so yet.
     
  8. racerx

    racerx Administrator
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    Cylinders are another world, tougher material, longer bore and tolerances are more critical. The machinist who has done cylinders for me over the past two decades has taught me a fair bit about the process...enough to know that there's a learning curve. Even with a dedicated boring mill, there are a number of variables, including temperature, that can %#@& with tolerances...by enough to make a difference. There are ways to compensate. After watching him overbore a number of cylinders, over the years, I'm confident enough...to know that I'm basically clueless and don't have enough time + opportunity to get through the learning curve and get anywhere near the artisanal mastery he's realized, let alone justify the cost of a boring mill. Am I trying to discourage you here? Absolutely NOT! What I am trying to do is give you some sense of what you will be facing so that , armed with that knowledge, you be better prepared for what will likely start out as a bumpy ride.

    Oddly enough, my current source for 39mm cylinder boring does them on a Bridgeport. From what I understand, the setup is more involved...but...there's an implication that the remainder of the process is easier. Maybe this is a good omen, for your setup...
     
  9. fatcaaat

    fatcaaat Well-Known Member

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    I've been sending my boring work to a guy I know for the past decade. He does a great job. However, if I have the ability to do this inhouse, obviously i'm going to try it. I have a few junk cylinders here to play with from a variety of different bikes. If i'm not precise enough to do cylinders, i'm not going to worry too much about it. It is definitely a skill that needs to be developed over time. Its been more than 20 years since I've done anything real with milling machines and i've jumped directly back in with CNC. GOing to have a learning curve for sure.
     
  10. racerx

    racerx Administrator
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    Yep, we're on the same page...start by practicing with some junk cylinders until you either a.) become proficient or b.) learn that it's outside of practical limits and enjoy a newfound appreciation for the known specialist(s) who can take on the specialized task, get it right every time and for a reasonable price.

    Look at it this way, you have real machining experience and you're a good 20 years younger than me...still plenty of time of de-rust your old skill set and develop a new one. Methinks you will be turning out some very interesting work, whether or not cylinder boring is part of your portfolio.(y)
     

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