[modeleng] Re: 12ba Screws

Hi to all,
While onn the subject of small BA bolts/screws and there bolt head sizes, Does 
anyone have a chart with the bolt sizes on, i know from using most sizes of 
threads through my working life that some of the spanner sizes overlap
ie:-5/16whit is very near 19/32A/F which is interchangeable to 15mm
And that some of the younger chaps i work with use 18mm and 21mm for some of 
the BSP fitting that we use at work which was based on the Whitworth spanner 
sizes originally.
Barrie if you are having a problem getting a spanner or socket for your 12BA 
bolts perhaps there might be an alternative in the current A/F or Metric range.

Also i know that during the war bolt head sizes were reduced to save on 
material did this happen across all British Standard bolts and threads.

I leave you this to ponder on.

Regards John Burridge


> Message date : Feb 24 2005, 12:05 AM
> From : "Ron Head" <ron.head@xxxxxxxxxxxxx>
> To : modeleng@xxxxxxxxxxxxx
> Copy to : 
> Subject : [modeleng] Re: 12ba Screws
> 
> Hi Barrie
> 
> I did say check before buying!  If they are not what Chronos advertise, why 
> not send them back?
> 
> Whilst on the subject of 12BA bolts, has anyone noticed that it is virtually 
> impossible to buy a 12BA spanner?  All the sets I have seen have 9BA x 11BA 
> as the smallest size.  These are not common thread sizes, but the spanner is 
> useful for 8BA and 10BA "one size smaller" heads.
> 
> I suppose if there was such a thing as a 12BA "one size smaller" bolt head, 
> you would need a 13BA spanner to fit it!
> 
> Has anyone measured up some 12BA nuts to see if these are correct A/F size?
> 
> Regards
> Ron
> 
> ----- Original Message ----- 
> From: "BarriePurslow" <Barrie@xxxxxxxxxxxxxxxxxxxxxx>
> To: <modeleng@xxxxxxxxxxxxx>
> Sent: Tuesday, February 22, 2005 11:48 AM
> Subject: [modeleng] Re: 12ba Screws
> 
> 
> > Incidentally I have just received a delivery of 12ba screws from Chronos 
> > and
> > they too are oversize. All the screws I have obtained, from several 
> > sources
> > appear to be from the same manufacturer, they are identical.
> 
> 
> 
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