|Threads Per Inch:||40|
|Finish:||P0 Bright Finish|
|Thread Type:||Imperial - UNC|
Taps are tools used by engineers for creating a female thread inside a hole. The tap is inserted into a special wrench and turned whilst cutting oil is used to lubricate the tap.
When forming a brand new thread in a blind hole, it is usually a three-stage process.
UNC stands for Unified National Coarse. It is a common imperial thread type with less threads per axial distance than its UNF equivalent.
Unified thread types (UNF and UNC) were introduced at the beginning of World War 2 to enable the interchangeability of machinery manufacturing between the USA, Canada and Great Britain. Still commonly found on a vast array of old machines and vehicles in the UK, UNF and UNC threads continue to be the standard thread in the USA and Canada.
When cutting shallow female threads, it may be possible to skip the third stage and just use the taper or second taps.
If tapping into a soft material it is possible to cut the thread with only a second tap.