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  1. jassco

    Datum reference frame of three-bearing arrangement shaft

    Hi, PetkovStoyan: "floating" means that the third bearing has extra clearance so that it won't "fight" against the other two major ones. Three bearing concept is very popular on precision long shafts. Many spindles in CNC machines (lathe for example) have 3 bearings. You position your spindle...
  2. jassco

    Datum reference frame of three-bearing arrangement shaft

    Hi, PetkovStoyan: Your language for datum is not accurate. You are talking about datum features rather than datum themselves. A datum is a coordinate system with three mutually perpendicular planes with an origin. You have 3 datum features (candidates) on your shaft. When an engineer designs...
  3. jassco

    STEP file conversion

    Hi, DesEngineer4: Is there an error message when you tried to convert your file? Best regards, Alex
  4. jassco

    Multiple Single Segment Positional Tol and Datums

    I think "unprofessional" is a better word.
  5. jassco

    Multiple Single Segment Positional Tol and Datums

    Hi, AMontembeault: Your datum feature D is too small to be qualified as a primary. Also, these 4 holes are supposed to be treated a pattern. You can locate and orient the pattern to datum feature A, B, and C with single or multiple segments FCF. Best regards, Alex
  6. jassco

    Proper GD&T for interrupted threads?

    Hi, ericscottf: Are you familiar with ISO GPS or ASME GD&T? If you are, you need to show your proposal. Then we can do critics. Best regards, Alex
  7. jassco

    GD&T: How to inspect tertiary datum feature position tolerances?

    Hi, DimaM: You will need to use a CMM machine to inspect position of 8+/-0.1 slot. If you don't have a CMM, you can inspect it using hard gages. Below are general proceedures on how to inspect it using CMM machine. 1. Place the part on a fixture to do an initial alignment; 2. Probe the center...
  8. jassco

    GD&T: How to inspect tertiary datum feature position tolerances?

    Hi, DimaM: The slot (dimension 8+/-0.1) is a feature of size. The position tolerance of this slot indicates how far off its derived medium plane (center plane of the slot) are allowed from axis of datum feature B which is perpendicular to datum feature A. Position of the slot has nothing to do...
  9. jassco

    Tolerancing of features to a center line of a thread

    I would not use the tapped hole as datum feature. If your thread hole is a precision one, generally it is inspected with thread plug. If I were you, I would use datum features below: Primary: OD (59mm) Secondary: Bottom surface Tertiary: 5.00 slots Your 9.00 hole should be two separate...
  10. jassco

    What is this symbol?

    Please take a look at URL below. https://www.gdandtbasics.com/parting-line/#:~:text=Parting%20Line%201%20Symbol%3A%202%20Definition%3A%20A%20parting,of%20the%20parting%20line.%20...%204%20All%20Symbols Best regards, Alex
  11. jassco

    What is this symbol?

    No. This is a dimension origin symbol. Parting line symbol is supposed to be diamond-shaped. Best regards, Alex
  12. jassco

    Question about controlling bow on extruded profile

    I think flatness callout is better. Alternatively, OP can control "straightness" using local and overall thickness or height. Best regards, Alex
  13. jassco

    Question about controlling bow on extruded profile

    Hi, ndpaintballer: Well, it depends on how it is used. I can't tell size of the profile from your sketch. An extruded vinyl profile with 200" long can be very flexible. Are you going to inspect it at free state or in a restraint condition? Best regards, Alex
  14. jassco

    How Many Datums are Too Many Datums?

    Hi, Glass_Half_Full: Design intents are not clear according to your sketch. What are those 16 holes? Are they threaded holes or holes for dowel pins? Most of those holes are for fastening purpose. You don't need tolerance of "zero at MMC" for threaded holes. Precision rails are normally...
  15. jassco

    Solidworks VBA to GET and SET dimensions on a sketch in an assembly model

    Hi, Deepak: I have not used Solidworks VBA for quite a while. I got a few codes from ChatGPT and Google/Bard and tried to GET and SET dimensions on a sketch in an assembly model. They did not work. Could you please show me statements to GET and SET dimensions using Solidworks' GET and SET...
  16. jassco

    Primary Datum on two planes

    Hi, MPSU: The datum targets (A1, A2 and A3) are in-line. They are not robust to be qualified as a primary datum. Position of M6 x 1.0 with maximum material boundary is questionable. For threads, we generally use projected tolerances (P with circle). Best regards, Alex
  17. jassco

    Position tolerance datums

    Hi, PtoMonty: So, you have a plate (let's call it "part A") with 6 holes two of which are dia. 9mm. You will press two pins into those dia. 9mm holes. What ("part B") will be attached to these two pins that stick out of the plate ("part A")? Is this "part B" a single part or multiple parts...
  18. jassco

    Position tolerance datums

    Hi, PtoMonty: You can't press 2 pins into two holes (dia. 9mm) with the position tolerances of dia. 0.5mm wrt to datum feature A unless the plate is made from soft materials, like lumber. Best Regards, Alex
  19. jassco

    Position tolerance datums

    Hi, PtoMonty: You mentioned that the actual part has two 9 mm holes. You can use these features below to locate dia. 11 holes. Primary: A (bottom of the part); Secondary:: One of the 9mm holes; Tertiary: The other 9mm hole. Alternatively, you can use these two datum features below...
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