metric, imperial, whitworth - could You explain?

[S.D.L.]

p.s.: I'd dream to take a plane on 16 jan to come to visit the cabin fever at York, Pennsylvania, but maybe it would be too expensive. Could You please indicate to me another great model engine show nearest to me? maybe in england?

One coming up in January, see here

http://www.meridienneexhibitions.co.uk/our-events-detail.php?id=0000000002

One of the best located north London, The best is in April or May at Harrogate

Here

http://www.theeventsoffice.co.uk/events.shtml

Steve Larner

 

[deverett]

In the Downloads section, I have put a thread equivalent file which can be used to compare British, American and Metric threads.

I hope it will help at least one of the members.

Dave
The Emerald Isle

 

[scoop]

Bentprop admits to using 26 t.p.i threads now and again.This is probably the old British brass thread which uses 26 t.p.i for all diameters of thread.Anybody else out there still using this thread system on a regular basis?

 

[mklotz]

In the Downloads section, I have put a thread equivalent file which can be used to compare British, American and Metric threads.

I hope it will help at least one of the members.

Dave,

Very nicely done. I've saved a copy.

Two minor nits...

You have the tap drill diameter units listed as "(thou)" although the value given is really inches.

It would be helpful to have the pitch of the individual BA sizes listed as you've done with BSW, BSF, etc.. - 0.9^N mm IIRC.

 

[Maryak]

Bentprop admits to using 26 t.p.i threads now and again.This is probably the old British brass thread which uses 26 t.p.i for all diameters of thread.Anybody else out there still using this thread system on a regular basis?

I think there's a 26 tpi thread system known as British Cycle or maybe Bicycle threads which can still be found as a boxed set. Maybe our UK colleagues can advise.

Best Regards
Bob

 

[deverett]

Bentprop admits to using 26 t.p.i threads now and again.This is probably the old British brass thread which uses 26 t.p.i for all diameters of thread.Anybody else out there still using this thread system on a regular basis?

Yes, I admit to using it and other constant pitch threads on a regular basis.

The old British Model Engineer thread series used a constant pitch; the pitch depending upon the diameter.

The series consisted of 26 tpi, 32 tpi, 40 tpi and (rarely) 60 tpi.

The 26 tpi series is the same as the BSB (British Standard Brass) threads, and go from 1/8" up to 5/8".
32 tpi is partly BSW (British Standard Whitworth) and partly BSF (British Standard Fine). and goes from 1/8" up to 1/2".
The 40 tpi series is, again, partly BSW and BSF and normally goes from 1/8" up to 1/4".

These threads were developed pre WW2 when model engineering in the UK was geared towards 2-1/2" gauge and below railways where the normal range of commercial threads were deemed unsuitable.

BA threads are a different series, and were commonly used in the electrical industry.


Marv. The chart was drawn up just so that I could have a quick comparison between the various threads specified on drawings, particularly in my case, US to UK as most of my threading tackle is the old Imperials stuff, although I am widening my base reluctantly - cost, my boy.

Dave
The Emerald Isle

 

[d-m]

Vary intresting to run across this thread, yesterday as I was working on putting the new front brake hoses in my 62 Austin Mini I could not find the nuts to hold them to the sub frame. With out thinking off I went to the parts store for some nuts. (thinking that it's all us fine thread LOL and not taking the time to count the thread) It turns out to be 26tpi ? Luckily Mini Spairs in the UK has them. Pic explanes why I haven't been posting in a wile lol it is keeping me vary busy and the wife wants it done by spring.
Dave

 

[baldrocker]

Wots AF then
BR

 

[Kermit]

http://www.sizes.com/tools/thread_whitworth.htm


neat website that one,
Kermit

 

[Maryak]

I think

AF is/was American Fine, similar to UNF. Also the term was often used to refer to OE spanners eg 9/16" AF (across the flats).

Oh what a tangled web we weave

Best Regards
Bob

 

[baldrocker]

Also the term was often used to refer to OE spanners

Maryak
You mean those that fit sizes unknown to man. :
BR

 

[Maryak]

Maryak
You mean those that fit sizes unknown to man. :
BR

Yep, them's the one maybe AF should be Alien Fit :

Best Regards
Bob