This second hand tap is an HSS-G threading tool for producing UNC internal threads in predrilled holes during workshop repair, maintenance, or small batch machining. You select it by the complete UNC 1.5/8 x 5 designation, ISO 529 design reference, Form D chamfer, tolerance class 2B, and right hand thread direction.
UNC denotes Unified National Coarse, an inch based thread series used on many North American components and service parts. HSS-G indicates a ground high speed steel execution, which supports defined cutting edges and repeatable hand tapping when lubrication and alignment are controlled. The right hand version is used when the drawing or mating part follows the standard fastening direction. The product data gives a core hole diameter of 36.3 mm and an overall length of 170 mm, so drilling, reach, and holder setup can be planned before cutting.
- Cut UNC internal threads in drilled holes where a controlled manual tapping process is required.
- Use Form D second chamfer after the starting operation when the thread must be guided toward full profile depth.
- Match the UNC 1.5/8 x 5 designation to the drawing, mating screw, and required right hand thread before machining.
- Use a tap wrench or guided hand tapping setup to keep the tool square to the hole axis.
- Prepare the core hole according to the stated 36.3 mm drilling value before starting the thread.
- Process: manual driving or assisted driving depending on your holder and machine setup
- Use: thread cutting, re tapping, and thread cleaning depending on condition
Note Use the second tap after the thread entry is started, keep the tap aligned, and stop if torque rises suddenly.
- ISO 529 design reference supports clear identification of the hand tap family in drawings and product data.
- Form D second geometry supports a staged hand tapping sequence between starting and finishing operations.
- HSS-G execution links the tool choice to ground high speed steel rather than an unspecified cutting material.
- Tolerance class 2B helps align the tapped internal thread with the required fit class.
- The stated core hole diameter gives a direct preparation value for drilling before tapping.
Drawbacks
- Manual tapping depends on operator alignment, so tilted entry can damage the internal thread.
- The tool is not a replacement for a guided machine tapping process when repeatability, feed control, or coolant delivery must be validated.
- Match the complete UNC 1.5/8 x 5 thread designation, direction, and tolerance requirement with the drawing or mating part.
- Prepare the core hole according to the documented drilling data.
- Chamfer the hole entry to support centred starting.
- Mount the hand tap in a suitable tap wrench.
- Align the hand tap square to the hole axis.
- Apply cutting fluid that fits the work material.
- Start the cut with steady torque and controlled feed.
- Reverse briefly at intervals to clear chips from the flutes.
- Withdraw the tool carefully after the required thread depth is reached.
- 1 piece Hand Tap Second ISO 529 Form D HSS-G - UNC 1.5/8 x 5
- Product type: Hand tap
- Tap stage: Second
- Standard: ISO 529
- Chamfer form: Form D
- Flute form code: N
- Thread system: UNC
- Thread size: UNC 1.5/8 x 5
- Thread standard: ANSI B 1.1
- Thread direction: Right hand thread
- Tolerance class: 2B
- Tool material or execution: HSS-G
- Overall length L1: 170 mm
- Thread length L2: 60 mm
- Shank diameter D2: 28 mm
- Square drive k: 22.4 mm
- Core hole diameter: 36.3 mm
- Packaging unit: 1 piece
- How do you confirm that this hand tap matches the required thread?
Match the full UNC 1.5/8 x 5 designation, right hand thread, tolerance class 2B, and thread standard ANSI B 1.1 against the drawing or mating part before you cut.
- What does UNC mean in the thread designation?
UNC denotes Unified National Coarse, an inch based thread series used on many North American components and service parts.
- Where can you find detailed technical notes for hand taps?
Technical information hand taps as PDF
- When do you use a second hand tap in the tapping sequence?
A Form D second hand tap is used after the thread has been started, so the profile can be developed further with controlled guidance.
- Where can you find an inch to millimetre reference for UNC work?
Inch to mm conversion table as PDF
- What is important when working with left hand inch threads?
Use a left hand tap only when the part drawing specifies LH or the mating fastener has a reverse tightening direction. A right hand tap would cut the wrong thread direction.
- Where can you find catalog information for this threading tool?
VD 23 catalog as PDF
- How do you reduce the risk of tap breakage during manual use?
Keep the tool aligned, use cutting fluid, avoid side load, and clear chips before torque becomes excessive.
Do you need help selecting or using the product?
Use the contact form
In this category: Threading tools
