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Conversion thinking error (SOLVED)

Discussion in 'General Discussion' started by Kunstmaan, May 14, 2020.

  1. Kunstmaan

    Kunstmaan Alibre Super User

    LS,
    From the shop I got a old drawing to create a 3D model
    Basicly I took the dimensions from the !:1 drawing supplied but by refining things, aading threads enz.
    I have the drawing attached.
    Puzzeled by the thread dimensions for example the 1 1/4" thread

    1 1/4"= 31.75mm but looking at the BSPP thread charts this dimensions is listed at 41,910 mm

    So question, what is the correct dimension??

    Berdie-Mareike
     

    Attached Files:

  2. DavidJ

    DavidJ Alibre Super User Staff Member

    BSP thread sizes relate to the nominal inside diameter of the pipe - the actual major/pitch/minor diameters will all be bigger than the nominal size (as the thread goes on the outside of the pipe).

    The nominal size may not even be match the inside diameter of the pipe as that varies depending upon pressure rating of the pipe.
     
  3. OTE_TheMissile

    OTE_TheMissile Alibre Super User

    Yeah pipe threads are best thought of as more of a designation rather than an actual measurement, IME.
     
    bigseb likes this.
  4. albie0803

    albie0803 Alibre Super User

    Do you have BSP threads in your dropdown? If not we can supply them for you.
     
  5. Lew_Merrick

    Lew_Merrick Alibre Super User

    Hi Albie -- Should you have them to hand, a "copy" to me (tangent@olympus.net) would allow me to "expand" my Whitworth Thread section on my "alibre_unicode_custom.thd" section posted here. -- Lew
     
  6. albie0803

    albie0803 Alibre Super User

    Lew, I thought I originally got them from you!

    anyway:

    ; English Generic
    ;
    *G 1/8 (BSPP),28,0.346,2B,0.383,0.337,0.360,2A,0.383,0.336,0.360,1000
    *G 1/4 (BSPP),19,0.464,2B,0.518,0.451,0.484,2A,0.518,0.449,0.484,1000
    *G 3/8 (BSPP),19,0.600,2B,0.656,0.589,0.622,2A,0.656,0.587,0.622,1000
    *G 1/2 (BSPP),14,0.748,2B,0.825,0.736,0.779,2A,0.825,0.733,0.779,1000
    *G 5/8 (BSPP),14,0.827,2B,0.902,0.810,0.856,2A,0.902,0.807,0.856,1000
    *G 3/4 (BSPP),14,0.965,2B,1.041,0.949,0.995,2A,1.441,0.945,0.995,1000
    *G 7/8 (BSPP),14,1.112,2B,1.189,1.097,1.143,2A,1.189,1.093,1.143,1000
    *G 1 (BSPP),11,1.211,2B,1.309,1.193,1.251,2A,1.309,1.188,1.251,1000
    *G 1-1/8 (BSPP),11,1.398,2B,1.492,1.375,1.434,2A,1.492,1.369,1.434,1000
    *G 1-1/4 (BSPP),11,1.555,2B,1.650,1.533,1.592,2A,1.650,1.523,1.592,1000
    *G 1-1/2 (BSPP),11,1.781,2B,1.882,1.765,1.824,2A,1.882,1.758,1.824,1000
    *G 1-3/4 (BSPP),11,2.008,2B,2.116,1.999,2.058,2A,2.116,1.891,2.058,1000
    *G 2 (BSPP),11,2.244,2B,2.347,2.230,2.289,2A,2.347,2.214,2.289,1000
    *Rc 1/8 (BSPT),28,0.3281,2B,0.383,0.337,0.360,2A,0.383,0.336,0.360,1000
    *Rc 1/4 (BSPT),19,0.4375,2B,0.518,0.451,0.484,2A,0.518,0.449,0.484,1000
    *Rc 3/8 (BSPT),19,0.5781,2B,0.656,0.589,0.622,2A,0.656,0.587,0.622,1000
    *Rc 1/2 (BSPT),14,0.7187,2B,0.825,0.736,0.779,2A,0.825,0.733,0.779,1000
    *Rc 3/4 (BSPT),14,0.9375,2B,1.041,0.949,0.995,2A,1.441,0.945,0.995,1000
    *Rc 1 (BSPT),11,1.1811,2B,1.309,1.193,1.251,2A,1.309,1.188,1.251,1000
    *Rc 1-1/4 (BSPT),11,1.5157,2B,1.650,1.533,1.592,2A,1.650,1.523,1.592,1000
    *Rc 1-1/2 (BSPT),11,1.7519,2B,1.882,1.765,1.824,2A,1.882,1.758,1.824,1000
    *Rc 2 (BSPT),11,2.2047,2B,2.347,2.230,2.289,2A,2.347,2.214,2.289,1000

    and just because I have them:

    Metric Bearing Locknut Threads

    ; Metric Generic
    ;
    *KM00-10x.75,0.75,9.25,1B,10,8.5,0.75,1A,10,8.5,0.75,2000
    *KM01-12x1,1,11,1B,12,10,1,1A,12,10,1,2000
    *KM02-15x1,1,14,1B,15,13,1,1A,15,13,1,2000
    *KM03-17x1,1,16,1B,17,15,1,1A,17,15,1,2000
    *KM04-20x1,1,19,1B,20,18,1,1A,20,18,1,2000
    *KM05-25x1.5,1.5,23.5,1B,25,22,1.5,1A,25,22,1.5,2000
    *KM06-30x1.5,1.5,28.5,1B,30,27,1.5,1A,30,27,1.5,2000
    *KM07-35x1.5,1.5,33.5,1B,35,32,1.5,1A,35,32,1.5,2000
    *KM08-40x1.5,1.5,38.5,1B,40,37,1.5,1A,40,37,1.5,2000
    *KM09-45x1.5,1.5,43.5,1B,45,42,1.5,1A,45,42,1.5,2000
    *KM10-50x1.5,1.5,48.5,1B,50,47,1.5,1A,50,47,1.5,2000
    *KM11-55x2,2,53,1B,55,51,2,1A,55,51,2,2000
    *KM12-60x2,2,58,1B,60,56,2,1A,60,56,2,2000
    *KM13-65x2,2,63,1B,65,61,2,1A,65,61,2,2000
    *KM14-70x2,2,68,1B,70,66,2,1A,70,66,2,2000
    *KM15-75x2,2,73,1B,75,71,2,1A,75,71,2,2000
    *KM16-80x2,2,78,1B,80,76,2,1A,80,76,2,2000
    *KM17-85x2,2,83,1B,85,81,2,1A,85,81,2,2000
    *KM18-90x2,2,88,1B,90,86,2,1A,90,86,2,2000
    *KM19-95x2,2,93,1B,95,91,2,1A,95,91,2,2000
    *KM20-100x2,2,98,1B,100,96,2,1A,100,96,2,2000
    *KM21-105x2,2,103,1B,105,101,2,1A,105,101,2,2000
    *KM22-110x2,2,108,1B,110,106,2,1A,110,106,2,2000
    *KM23-115x2,2,113,1B,115,111,2,1A,115,111,2,2000
    *KM24-120x2,2,118,1B,120,116,2,1A,120,116,2,2000
    *KM25-125x2,2,123,1B,125,121,2,1A,125,121,2,2000
    *KM26-130x2,2,128,1B,130,126,2,1A,130,126,2,2000
    *KM27-135x2,2,133,1B,135,131,2,1A,135,131,2,2000
    *KM28-140x2,2,138,1B,140,136,2,1A,140,136,2,2000
    *KM29-145x2,2,143,1B,145,141,2,1A,145,141,2,2000
    *KM30-150x2,2,148,1B,150,146,2,1A,150,146,2,2000
    *KM31-155x3,3,152,1B,155,149,3,1A,155,149,3,2000
    *KM32-160x3,3,157,1B,160,154,3,1A,160,154,3,2000
    *KM33-165x3,3,162,1B,165,159,3,1A,165,159,3,2000
    *KM34-170x3,3,167,1B,170,164,3,1A,170,164,3,2000
    *KM36-180x3,3,177,1B,180,174,3,1A,180,174,3,2000
    *KM38-190x3,3,177,1B,190,184,3,1A,190,184,3,2000
    *KM40-200x3,3,187,1B,200,194,3,1A,200,194,3,2000
     
  7. Lew_Merrick

    Lew_Merrick Alibre Super User

    Hi Albie -- Whereas I have distributed BSW (British Standard Whitworth) and BSF (British Standard [Whitworth] Fine) datasets for alibre_unicode_custom.thd usage, I do not recall ever having gotten into Parallel Whitworth Pipe Threads of Bearing Locknut Whitworth Threads. More (confirmed) data is good! -- Lew
     
  8. albie0803

    albie0803 Alibre Super User

    These are METRIC bearing locknuts
     

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