[rollei_list] Re: ?? True Sizes of Tripod Mounting Holes

I 'feel Jerry's pain'.  I'm in the commercial
satellite business.  We buy from all over the world
(who mostly use metric sizes).  But we ask for tapped
10-24 holes (as just one example) for the purchased
hardware we bolt into what we build.  The rest of what
we do ourselves is to U.S./English standards.

JJ

--- Jerry Lehrer <glehrer@xxxxxxxxxx> wrote:

> RUGers
> 
> As usual, Richard is right.  The thread form is 60
> degrees, NOT the 
> Whitworth 55 degrees.
> 
> The word Whitworth makes my skin crawl, thinking of
> my early days 
> working on my MG TD,
> Cad-Allard,  Jaguar or AC-Bristol.  Al those used a
> mixture of thread 
> und wrench standards.
> I only reached fastener sanity with Porsche and the
> Metric system.
> 
> Unfortunately, my working life is spent in the only
> industry that still 
> uses the US Inch standard;
> the commercial aircraft industry.  Yes, even the
> most advanced airplane 
> in the world, the Boeing
> Dreamliner 787 uses inches.
> 
> Jerry
> 
> 
> Richard Knoppow wrote:
> >
> > ----- Original Message ----- From: "Frank Dernie" 
> > <Frank.Dernie@xxxxxxxxxxxxxx>
> > To: <rollei_list@xxxxxxxxxxxxx>
> > Sent: Tuesday, August 28, 2007 2:51 AM
> > Subject: [rollei_list] Re: ?? True Sizes of Tripod
> Mounting Holes
> >
> >
> > This doesn't help but I thought the two standards
> were both Whitworth
> > thread form not UNC.
> > Frank
> >
> > On 28 Aug, 2007, at 03:14, Laurence Cuffe wrote:
> >
> >>
> >> On Monday, August 27, 2007, at 07:50PM, "SandyF."
> <sbf70@xxxxxxxx>  
> >> wrote:
> >>> According to the Unified Standards, the
> following applies to UN  
> >>> Coarse Series Threads
> >>>
> >>> Size      Basic      Threads/inch   Basic
> >>>            Major                           
> Pitch
> >>>            Dia. (in)                        Dia.
> (in)
> >>> 1/4-20   0.2500           20          0.2175
> >>> 3/8-16   0.3750           16          0.3344
> >>> The above information straight from my
> Machinery's Handbook, 21st ed.
> >>> S. B. Friedman, aka
> >>> SandyF  -----  Ö¿Ö¬
> >
> >
>
----------------------------------------------------------------------
> >
> >    I found a thread standard in a reprint of a
> book I think originally 
> > printed by the National Camera School.
> >    For American cameras the thread was covered by
> ASA standard PH 
> > 3.6-1952  This specifies a 1/4-20 UNC-1A thread
> according to Unified 
> > American Screw Threads B1.1-1949.
> >    The standard is slightly different than the one
> given above by Sandy.
> >
> > Major Diameter (inches) Pitch Diameter (inches)
> Minor Diameter (inches
> > Max   0.2489            0.2164                 
> 0.1876
> > Min   0.2367            0.2108                 
> ------
> >
> > Recommended length: Small cameras = 0.175"; Large
> cameras, 0.340"
> >
> >    The standard also has a recommendation for an
> oversize thread to 
> > account for build up during plating.
> >
> >    Screw Socket Dimensions: 1/4-20 UNC-1B
> > Minor Diameter (inches)  Pitch Diameter (inches) 
> Major Diameter (inches)
> > Min    0.1959            0.2175                  
> 0.2500
> > Max    0.2067            0.2248                  
> ------
> >
> >
> >    A second ASA standard, ASA PH3.7-1952, applies
> to heavy duty 
> > cameras and European cameras. The thread specified
> is: 3/8-Inch-16 
> > UNC-1A American Unified Screw Threads ASA
> B1.1-1949 with the following 
> > dimensions:
> >
> > Major Diameter (inches  Pitch Diameter (inches)
> Minor Diameter (inches
> > Max  0.3737             0.3331                 
> 0.2970
> > Min  0.3595             0.3266                 
> ------
> >
> > Screw Socket Dimensions: 3/8-inch 16 UNC-1B
> according to PH B1.1-1949
> >
> > Minor Diameter (inches)  Pitch Diameter (inches) 
> Major Diameter (inches
> > Min   0.9373             0.3344                  
> 0.3750
> > Max   0.3182             0.3429                  
> ------
> >
> > This standard also gives recommended dimensions
> for a thread adaptor 
> > to the American size thread.
> >
> > ------------------
> >
> > ---
> > Richard Knoppow
> > Los Angeles, CA, USA
> > dickburk@xxxxxxxxxxxxx
> >
> > ---
> > R
> 
> ---
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