No 4 x 0.66 BA HSS Tap Set - Goliath

About this item:

• No 4 x 0.66 BA HSS Tap Set - Goliath
• HSS Bright Finish BA Hand and Machine Tap Set (T, I, B).
• HSS Straight Flute Short Machine and Hand Taps.
• These general purpose taps are ideal for creating new threads in a wide variety of materials.
• Goliath HSS taps provide a high hardness to toughness ratio, compressive and tensile strength, good abrasion resistance and resistance to micro-chipping, ensuring a long tool life.
• British Association thread form - in 1884 the British Association for the Advancement of Science adopted a thread form and series, primarily for use in precision equipment.
• It was inspired by one used in the Swiss watch and clock industry, and was formerly sometimes called the Swiss Small Screw Thread System; but is now just referred to as the BA series.
• Like the Whitworth thread, it has a rounded root and crest, but the included angle is 47.5º.
• Despite the date of origin and the British sponsorship, the BA is a metric series.
• Not only is it based on the metre, but the thread frequency is specified in terms of round numbers in the pitch sequence, with threads per metre allowed to fall where it may.
• Taper Taps have a lead of eight threads and are used as a starting tap in difficult or high precision holes.
• Intermediate Taps have a lead of four threads and are used in most general purpose applications to cut a thread true to a pre-drilled pilot hole.
• Bottoming Taps have a lead of two threads and are used to ensure minimum thread run-out when tapping to the bottom of a blind hole.
• Bottoming Taps are typically preceded by the use of a Taper or Intermediate Tap.
• Manufactured from HSS this general purpose tap is designed for use in medium tensile materials and is for hand or general machine use.