American threads

[SUNRAY]

They were - I have countless like the one I illustrated.
Very true, but that's a big "if", at least for me.

When I am working on something (car, washing machine or whatever) when I first have a need for a spanner for a particular nut, screw or bolt, I will very often not even have sight of, let lone knowledge of the type and size of, the associated thread - but what I can see, feel or even measure, is the required 'across flats' dimension of a spanner that will fit it - and that is the basis on which I necessarily have to select my 'first try' spanner!

Kind Regards, John

agreed

 

[Keithmac]

For me you look at the head, guesstimate the size and try the socket/ spanner for a good fit.

You can tell before you apply any torque if it's likely to round or not.

I could probably pull 4 or 5 M6x1 metric fasteners out of my tool box with 4 different heads (10mm across flats, 5mm Allen socket, spline, torx).

As said above when the fastener is fitted you can't see the threads.

 

[SUNRAY]

For me you look at the head, guesstimate the size and try the socket/ spanner for a goof fit.

You can tell before you apply any torque I it's likely to round or not...

...As said above when the fastener is fitted you can't see the treads.

Yes I agree with all of this, however people tend not to be too conciencious in my experience.

 

[JohnW2]

For me you look at the head, guesstimate the size and try the socket/ spanner for a good fit. ....
You can tell before you apply any torque if it's likely to round or not. ... As said above when the fastener is fitted you can't see the threads.

Exactly. In fact, despite the discussion, I presume that's what most/all of us do most of the time, given that, as we have both said, one usually cannot even see, let alone measure or determine the type of, the threads when one needs to choose a spanner/socket!

Kind Regards, John

 

[SUNRAY]

Exactly. In fact, despite the discussion, I presume that's what most/all of us do most of the time, given that, as we have both said, one usually cannot even see, let alone measure or determine the type of, the threads when one needs to choose a spanner/socket!

Kind Regards, John

I would say that most regular users of spanners, that expressly excludes many modern day personel who only own AJ's, have an idea of what bolts they're likely to be working with when they see a head or nut.
I'm not trying to say that any one (including me) can accurately state what the bolt/thread is by seeing the head for the first time but the shape and proportions of UNC/UNF are different to Whitworth/British Standard are different to Metric are different to British association if made according to their relevant standards.

 

[Keithmac]

I was watching Fred Dibnah repairing one of his Traction Engines and he commented on how each nut and bolt were hand made and matched as pairs.

Amazing when you think at one point there was no standards at all for nuts and bolts and all were hand made.

 

[JohnW2]

I would say that most regular users of spanners, that expressly excludes many modern day personel who only own AJ's, have an idea of what bolts they're likely to be working with when they see a head or nut. ... I'm not trying to say that any one (including me) can accurately state what the bolt/thread is by seeing the head for the first time but the shape and proportions of UNC/UNF are different to Whitworth/British Standard are different to Metric are different to British association if made according to their relevant standards.

Be all that as it may, I still think that, as Keithmac (and myself) has said, most of us usually simply look at the nut/head and make an intelligent guess as to which spanner to try first - and all that usually without even looking at what is written on the spanner - so, quite honestly, it makes no difference to me whether the spanner is marked in terms of 'across flats' or a thread size (or not 'marked' at all)!

Kind Regards, John

 

[JohnW2]

I was watching Fred Dibnah repairing one of his Traction Engines and he commented on how each nut and bolt were hand made and matched as pairs. Amazing when you think at one point there was no standards at all for nuts and bolts and all were hand made.

Indeed - but that, of course, is not limited to nuts and bolts - it applies equally to almost everything which we now expect to come in 'standard sizes'! Anyone who tried to replace some of the bricks in my house would soon learn that

Kind Regards, John

 

[fixitflav]

A general comment - BSF/BSW spanners are (when you come across them) marked with the bolt diameter, not the head AF.
As this is the electrical section I'm surprised it's mostly about bolt threads. Electrical threads used to be eg PG7, PG21. PG for Panzer Gewinde (Panzer thread, but why I don't know) till superseded by metric electrical (not the same as metric bolt threads, obviously)
And there's plenty of other threads out there.

 

[JohnW2]

A general comment - BSF/BSW spanners are (when you come across them) marked with the bolt diameter, not the head AF.

Indeed so - like the one I illustrated in post #23.

As this is the electrical section I'm surprised it's mostly about bolt threads. Electrical threads used to be eg PG7, PG21. PG for Panzer Gewinde (Panzer thread, but why I don't know) till superseded by metric electrical (not the same as metric bolt threads, obviously) ... And there's plenty of other threads out there.

I must say I've never heard of PG threads - my 'distant past' recollections of electrical accessories (in the UK) are all of BA threads.

What do you mean by "... metric electrical (not the same as metric bolt threads, obviously) ..."? What is a "metric electrical thread"? Is, for example, the (electrically) ubiquitous 3.5mm thread any different from that of an M3.5 bolt?

Kind Regards, John

 

[fixitflav]

Indeed so - like the one I illustrated in post #23.
I must say I've never heard of PG threads - my 'distant past' recollections of electrical accessories (in the UK) are all of BA threads.

What do you mean by "... metric electrical (not the same as metric bolt threads, obviously) ..."? What is a "metric electrical thread"? Is, for example, the (electrically) ubiquitous 3.5mm thread any different from that of an M3.5 bolt?

Kind Regards, John

Here's a chart with various threads. I haven't worked on this sort of thing for some years so a bit rusty! I think metric electrical (and earlier PG) threads were for cable glands, conduits etc. The thread pitch, and some of the diameters are quite different from metric bolts. AFAIK BA (British Association) was another bolt thread to add to BSW, BSF, UNC, UNF etc. Thankfully it's pretty much disappeared now.

 

[SUNRAY]

A general comment - BSF/BSW spanners are (when you come across them) marked with the bolt diameter, not the head AF.
As this is the electrical section I'm surprised it's mostly about bolt threads. Electrical threads used to be eg PG7, PG21. PG for Panzer Gewinde (Panzer thread, but why I don't know) till superseded by metric electrical (not the same as metric bolt threads, obviously)
And there's plenty of other threads out there.

PG threads are far from withdrawn.

 

[JohnW2]

PG threads are far from withdrawn.

Maybe not but, as I said earlier, I'd never heard of them!

Kind Regards, John

 

[fixitflav]

PG threads are far from withdrawn.

OK, I thought PG was no longer used, but I'm not an electrical engineer, as well as being out of touch

 

[fixitflav]

Is, for example, the (electrically) ubiquitous 3.5mm thread any different from that of an M3.5 bolt?

To come back to this, the electrical threads I was referring to were for things with a hole like conduits, with minimum OD (for PG7) 12.5mm. I assume 3.5mm dia is for things like threaded studs for spade connections. Do you have a spec for them? I don't think it's the same as a metric bolt, as 3.5mm is not a standard diameter. Bolt standards are M1.6, M2, M2.5, M3, M4, M5, M6, M8 ...etc.