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Alignment using only two datums

I've attached an image of a part I'm working on and I always get confused by seeing only two datums I'm not sure how to go about creating my alignment my alignment I know this is basic stuff but I'm with limited training on top of being the only operator In the company so there is no mentor/co-worker to turn to please keep answers simplistic as I previously stated I am basically self-taught and terminology isn't my strong suite as of yet. Please and Thanks to all in advance. I can add more info as needed just let me know. 

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  • Looking at this I would suggest creating a plane on the A datum (looks like it's the counter bore of the hole) and levelling to that and setting it as your Z origin.
    Then measure the 2 Ø8.8 to create a midpoint as others have mentioned and set that as x, y origin.
    I would rotate between the two Ø8.8 bores and then rotate out the error so that the part is aligned with drawing.
    To do this take the x and y between the two bores x=65 y=5.69 use trig to find the angle: Tan-1(5.69/65) = 5.00283153° and rotate the alignment by this figure.

  • That worked flawlessly... now that have my MAN/DCC align is it good practice to then remeasure those datums with more hits to find any deviations during my dimensioning process....

    One more thing as of right now anyway ,Grin I've for the most part taught myself how to read the FCF W, or W/O modifiers (MMC, LMC) unfortunately this is where I'm stuck, I know datum B is in some cases to be considered at mmc aka the most material smallest hole but how or what is best practice to measure, and dimension the call out let's say 

    ø6.5 ± 0.13
    (2)plus.
    |Position| 0.25(m)|A|B(m)|

    I had to use the word "Position" in place of the symbol.

    Again, thanks for everyone input!!!

  • MMC/LMC does not apply to datums AS datums, it is the same symbol but is maximum material boundary (MMB) (same for LMB).  It is the amount the PART can be shifted to try to get the part in tolerance (as if it were on a hard gage with straight pins in the holes, you can shift the part around on the pins).  The 0.25(M) is MMC, but the A|B(m)| is MMB.  Nice, eh?

  • I think I caught what you were throwing...SO what's the difference between the last EXAMPLE I asked about, And the call out FCF for datum B?

    I know this probably day one material but idk if you noticed where I mentioned I'm basically learning as I go with the help of others such as yourself. my apologies for all this Q/A there is so much information to take into account along with rules and best practices etc. so I really appreciate your patience with this

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  • I think I caught what you were throwing...SO what's the difference between the last EXAMPLE I asked about, And the call out FCF for datum B?

    I know this probably day one material but idk if you noticed where I mentioned I'm basically learning as I go with the help of others such as yourself. my apologies for all this Q/A there is so much information to take into account along with rules and best practices etc. so I really appreciate your patience with this

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