It’s Sunday afternoon and I’ve spent most of the morning drilling and ‘tapping’ ½ inch holes in steel for my current project. I recently bought a tap and die set (from a Chinese import shop!) which has a ½ NC 13 tap.
I went to a local hardware store and purchased ½ inch bolts and to my horror found that they were binding after the first revolution. I re-tapped the holes but the problem remained.
I returned to the hardware store to seek answers only to be told that the likely cause is that the ½ inch bolts they stock are Whitworth thread. (I couldn’t find any Whitworth tap and die kits).
Whitworth?
I tried a few other hardware stores but they all sell the same ½ inch bolt.
There are no engineering firms open.
A quick Google on Whitworth reveals…
“Most of the coarse threads share the same threads per inch which means BSW nuts can be screwed onto UNC bolts and vice-versa. The exception to this being ½ inch -- ½ inch BSW is 12 threads per inch and ½ inch UNC is 13 threads per inch.” British Fasteners
I was wondering if there are any Australians on the forum who can tell me if ½ inch bolts can be purchased in this country with a NC 13 thread, (and if so, is this a specialised and expensive item?) or am I ‘screwed’?
Reminds me of reading about the army & RAF trying to explain to Churchill how complicated it was doing maintainance in the desert, then I imagine what it would be like if none of the spanners work...
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