screw sizes

[Brian]

When writing the book on the Dark lady clock I am thinking of including
a chart for changing B.A. size screws To A.N.F for all of you across the pond. I.E
BA 2 =A.N.F 10
4-------- 6
6-------- 4
8-------- 3
10------- 1
12------- 0
I think these are nearest equivalents
Now as I am totally ignorant of what is available in the US do you think this is a good idea or not
Brian

[arvidj]

I can not find a reference to 'A.N.F' threads any where on Google. Is it possible you meant UNF?

Never mind. It appears as though 'AN' means American National and 'UN' means Unified National.

[Sunset Machine]

The book says the Unified National series was accepted by the UK, the US and Canada a long time ago. It has replaced the American National. Generally speaking, when we go to the hardware store, you have a choice of UNC or UNF (class 2, I believe).

The attachment is from Machinery's Handbook, 1979. Hoping to avoid another copyright blunder, I'm fairly certain posting a single page or two comes under fair use, unlike a copy of the whole book I had linked to previously..

As to being a good idea, I think what you have in mind is a GREAT idea.

[TomG]

Brian,

We primarily use the Unified Thread Standard over here. Each size has a coarse and a fine pitch associated with it as you can see in the chart. The fine pitches are generally closer to the the mm pitches you guys use over there. Common diameters range from #0 (1.524mm) to #10 (4.826mm). Common pitches are 80 for the #1 (.3175mm), 56 for the #2 (.4536mm), 40 for the #4 (.635mm) ad 32 for the #6, #8 and #10 (.7938mm). I don't have a clue how these compare to the BA thread system.

Tom

[Brian]

Thanks Lads that helps a lot, I am trying to make this a easy build for all, so locally available threads will help keep costs down.
For your interest this is the B A system.

  img221.jpg (Size: 30.46 KB / Downloads: 64)

Smallest is .25 mm how you tap that I just cant imagine

Brian.

[Tony Wells]

Carefully, Brian....very carefully.


Small correction, Tom. #10 UNC is 24 TPI. 32 would be UNF. The other sizes you listed for UNC. And there is the oddball #12-24 once in a long while. But it's avoided in general. And a little hard to find at the local hardware shop.