[SEL] drill sizes for 7BA clear and 7BA tap

[John Hall]

Thanks for the info. It still amazes me the odd ball threads that keep 
coming up. If there aren't enough thread types and sizes already, we have a 
customer that uses really fine pitches and 60 deg form but bastard 
diameters.

John
----- Original Message ----- 
From: "John Culp" <johnculp at chartertn.net>
To: "The SEL email discussion list" <sel at lists.stationary-engine.com>
Sent: Sunday, September 24, 2006 12:34 PM
Subject: Re: [SEL] drill sizes for 7BA clear and 7BA tap


> Not really. B.A. is British Association. A standard for small threads, 
> below about 1/4". Dates back to the 1800s, but the dimensions are actually 
> metric-based. The thread profile is much narrower than Whitworth. Details 
> are online on a bunch of sites, some of which have already been cited.
>
> Interestingly enough, the small screws on Mauser rifles are B.A., and the 
> big threads on the barrel are Whitworth. The original machine tools Mauser 
> Werke used came from England, and all subsequent Mauser licensees have 
> stuck with the English thread standards.
>
> If anyone needs any B.A. #1 x 1" cheesehead screws or hex nuts, let me 
> know. I had to order a pretty good bunch from http://britishfasteners.com/ 
> to meet their minimum order when I tore up the funny looking round, 
> slotted nut on the barrel band of my Czech-built M98/29 Persian Mauser.
>
> John
>
> On Sep 24, 2006, at 8:12 AM, John Hall wrote:
>
>> Try this site anytime you run into oddball threads---I use them at work 
>> quite often.
>> www.marylandmetrics.com
>>
>> Am I correct that BA threads are the same as Whitworth?
>>
>> John Hall
>
>
> John Culp
> Bristol, Tennessee, USA
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