Hand Tap Taper JIS B-4430 Form A HSS-G - UNF 7/8 x 14

• Create internal threads during repair work or low volume production where manual tapping is practical.
• Process: manual driving or assisted driving depending on your holder and machine setup
• Use: thread cutting, re tapping, and thread cleaning depending on condition
• Use cutting fluid suitable for the material and keep the tool square to the hole axis.

Note Keep the setup clean and check the thread with a gauge or mating part after cutting.

• Manual control over torque and alignment during thread cutting
• Suitable for workshop repair, maintenance, and low volume production
• Practical for starting threads in assembled or hard to fixture parts
• Ground tool geometry can support consistent cutting action

• High torque applications can require stronger tooling and rigid fixturing
• Manual operation is slower than automated production methods

1. Prepare the hole with the correct pre machining and add a small entry chamfer.
2. Secure the workpiece so it cannot move during tapping.
3. Clamp the tap in a suitable tap wrench and bring it to the hole axis squarely.
4. Apply a cutting fluid matched to the workpiece material.
5. Start the first turns with steady pressure while keeping alignment.
6. Advance with controlled torque and reverse slightly at intervals to clear chips from the flutes.
7. Continue until the required thread depth is reached, then back out smoothly.
8. Clean the thread and inspect fit with a gauge or mating part.

• 1 piece Hand Tap Taper JIS B-4430 Form A HSS-G - UNF 7/8 x 14

• Product type: Hand Tap
• Standard: JIS B-4430
• Tool material: HSS-G
• Thread designation: UNF 7/8 x 14
• Thread system: UNF
• Chamfer form: Form A

How do you select the correct thread designation for this tool
Match the designation UNF 7/8 x 14 to the drawing and mating part, then confirm that the hole type and process match the tool design.

Which holder is typically used for manual tapping
A tap wrench that clamps the square shank is the typical choice, and you keep the tool axis aligned to the hole to reduce side load.

What does the stage name in the product name tell you
Stage names such as rougher, intermediate, finisher, taper, or bottoming indicate the intended chamfer and entry behavior, so you can plan the tapping sequence and hole depth.

Which workpiece materials are typical for this threading tool
Thread cutting tools are commonly used in steels, cast iron, and many non ferrous alloys, but you should adapt lubricant choice and process control for hard, sticky, or abrasive materials.

What does UNF mean in the thread designation
UNF means Unified National Fine, an inch based thread series used where finer adjustment or more engaged threads are desired.

Do you need lubrication and how do you manage chips
Use a cutting fluid suitable for the material to reduce friction, and clear chips from the flutes during the process to keep torque stable.

Where can you find additional technical information for selection and standards
For an overview of threading tools and related standards, refer to the VD 23 catalog as PDF.