[rollei_list] Re: ?? True Sizes of Tripod Mounting Holes
- From: John Jensen <jwjensen356@xxxxxxxxxxxxx>
- To: rollei_list@xxxxxxxxxxxxx
- Date: Tue, 28 Aug 2007 21:10:21 -0700 (PDT)
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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