This bottoming hand tap is an HSS-G threading tool for producing metric ISO internal threads in predrilled holes during workshop repair, maintenance, or small batch machining. You select it by the complete M 18 x 2.5 designation, ISO 529 design reference, Form C chamfer, tolerance class ISO2 6H, and left hand thread direction.
M denotes an ISO metric thread with nominal diameter and pitch in millimetres, commonly used for machine screws and general fastening in mechanical engineering. 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 left hand version is selected when the thread must tighten opposite to standard right hand fastening direction. The SML product data gives a core hole diameter of 15.5 mm and an overall length of 110 mm, so drilling, reach, and holder setup can be planned before cutting.
- Cut metric ISO internal threads in drilled holes where a controlled manual tapping process is required.
- Use Form C bottoming chamfer to continue the thread closer to the bottom of a blind hole after a suitable lead-in exists.
- Match the M 18 x 2.5 designation to the drawing, mating screw, and required left 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 15.5 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 a suitable starting sequence before bottoming, 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 C bottoming geometry supports finishing threads near the base of blind holes after thread entry has been prepared.
- HSS-G execution links the tool choice to ground high speed steel rather than an unspecified cutting material.
- Tolerance class ISO2 6H 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.
- Left hand execution covers reverse tightening thread requirements without using a right hand tap incorrectly.
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 M 18 x 2.5 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 Bottoming ISO 529 Form C HSS-G left hand thread - M 18 x 2.5 LH
- Product type: Hand tap
- Tap stage: Bottoming
- Standard: ISO 529
- Chamfer form: Form C
- Flute form code: N
- Thread system: M
- Thread size: M 18 x 2.5
- Thread standard: DIN 13
- Thread direction: Left hand thread
- Tolerance class: ISO2 6H
- Tool material or execution: HSS-G
- Special feature: Linksgewinde
- Overall length L1: 110 mm
- Thread length L2: 37 mm
- Shank diameter D2: 14 mm
- Square drive k: 11.2 mm
- Core hole diameter: 15.5 mm
- Packaging unit: 1 piece
- How do you confirm that this hand tap matches the required thread?
Match the full M 18 x 2.5 designation, left hand thread, tolerance class ISO2 6H, and thread standard DIN 13 against the drawing or mating part before you cut.
- What does M mean in the thread designation?
M denotes an ISO metric thread with nominal diameter and pitch in millimetres, commonly used for machine screws and general fastening in mechanical engineering.
- Where can you find detailed technical notes for hand taps?
Technical information hand taps as PDF
- When do you use a bottoming hand tap in a blind hole?
A Form C bottoming hand tap is used after the thread has been started, so the usable thread can continue closer to the base of a blind hole.
- Why does the core hole diameter matter before tapping?
The core hole diameter of 15.5 mm controls how much material the hand tap removes and how much torque is needed during cutting.
- What should you check before ordering a metric hand tap?
Check diameter, pitch, tolerance class, hand tap stage, and right hand or left hand direction against the drawing before ordering.
- 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
