FWIW -
BSP threads - British Standard Pipe are the same, size for size as
BSTP threads - British Standard Taper Pipe.
!/2" BSTP and 1/2" BSP are both 14 tpi and have the same thread depth
(0.0457") and face angles (271/2 degs.)
The difference is that the BSTP is machined at a 1:16 taper. BSP is a
parallel thread.
The nominal diameter is measured at a distance from the narrower end equal
to the diameter, so a 1/2" plug is one that measures 1/2", 1/2" from the
small end.
Got that? (gg)
Guy
UK
-----Original Message-----
From: Bill & Cindy <fatboy@metro.net>
To: spridgets@autox.team.net <spridgets@autox.team.net>
Date: 11 February 1999 01:37
Subject: Re: Pipe thread thread
>At 11:48 AM 2/10/99 -0800, you wrote:
>>
>>".....I'm pretty sure I checked the threads with a thread gauge before
>>I replaced
>>the differential plugs with the Ford ones, but now you
>>have got me curious and I'm gonna check 'em again... next time I run
>>across the old ones in my junk box.
>>
>>
>>Bill & Cindy
>>Santa Rosa, CA "
>>
>>Please advise when you have your results on the axle plug threads. I
>>like to replace about any threaded part or fastener when I diassemble
>>something on an older car, so I'd like to know which pipe-threaded
>>parts I can replace at the local hdwe store.....
>>
>>Thanks -
>>
>>MD
>
>
>Michael,
>
>I found the old differential plugs that I removed from our 69 MKIV Sprite.
>
>They are a tapered thread plug with 14 threads per inch. The roots of each
>plug measures approximately .781" and 792". The crowns of each plug measure
>approximately .834" and .840".
>
>Now...reference data indicates that both USP and BSP 1/2 pipe is 14TPI.
>Same data also states that a 1/2 BSP diameter is .825"...how they establish
>a nominal diameter for a taper is unknown to me.
>
>Back to the real world. Are the original plugs BSP or USP? I dunno? Do know
>that the USP ones fit and do not leak.
>
>As a final thought on the matter...Lindsay Porter does not state in his "MG
>MIGDET & AUSTIN-HEALEY SPRITE Purchase and Restoration Guide" page 295,
>that the differential plugs are 1/2 BSP ...as a matter of fact...he doesn't
>reference them at all!
>
>So...I guess the question remains unanswered.
>
>How 'bout it list...jump right in here and help me confuse the matter even
>more.
>
>>
>>
>>
>>_________________________________________________________
>>DO YOU YAHOO!?
>>Get your free @yahoo.com address at http://mail.yahoo.com
>>
>>
>Bill & Cindy
>Santa Rosa, CA
>
>98 Sea Ray 190 BR
>96 Yellow Lab
>94 Ford F150 4x4
>91 Tioga Montara
>72 Midget parts car
>69 Sprite driver
>Assorted teen-agers
>
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