gas burners

[duncan webster 1Participant @duncanwebster1]

I've been looking at some USA sites where they seem to be well on with gas fired locos. One refers to #67 holes. In UK speak this would be 0.032" Can any of our transatlantic readers advise is US the same or do they do their own thing

[duncan webster 1Participant @duncanwebster1]

[John OlsenParticipant @johnolsen79199]

Wikipedia has a table of US number drill sizes and gives 0.032 for #67. Wikipedia link

I believe that US wire gauge sizes differ slightly from British Standard, I'm not sure if that applies to drill gauge sizes or not.

I've never quite seen the point of assigning arbitrary numbers to designate sizes that can be perfectly well specified with a linear dimension. Maybe it is a deliberate attempt to make things more arcane and complicated?

regards

John

[Nigel Graham 2Participant @nigelgraham2]

John –

I wondered what might be the nearest standard metric drill equivalent for that #67

It is 0.8mm, only 0.13mm smaller. (2% reduction in area if my sums are right: the ratio of the [diameters squared] ).

'

Giving drill, wire and sheet-thickness sizes in number and letter series probably goes back to the 19C; and yes, the Americans do have their own sizes for them! It probably did simplify things then, by establishing standards from contemporary trades' practices.

They have been obsolescent for quite a while now, for even without metrimification, as you say, a normal linear dimension, inch or mm, is much more logical and simple!

Even for BS, BSP and BA threads or their American equivalents the normal 0.1mm-increment twist-drills cover their tapping and clearance sizes well enough. (BA of course, is metric although specified in "thous" .)

Letter and Number drills are still obtainable; but I forget when I last used mine, and the fractional-inch and millimetric drills are those specified for screws by the Tracy Tools chart and the Book of Zeus.

[peak4Participant @peak4]

Posted by John Olsen on 20/10/2021 21:08:08:

……………..

I've never quite seen the point of assigning arbitrary numbers to designate sizes that can be perfectly well specified with a linear dimension. Maybe it is a deliberate attempt to make things more arcane and complicated?

regards

John

John, don't forget that wire gauges were around before folk were able to accurately measure small distances.

The Association of Anaesthetists has quite a good page on it
https://associationofanaesthetists-publications.onlinelibrary.wiley.com/doi/full/10.1046/j.1365-2044.1999.00895.x

Bill

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