This 3 piece hand tap set to DIN 352 in HSS-G is made for cutting a left hand internal thread in UNC 1/4 x 20 LH. Use it when the workpiece, drawing, or mating component requires this exact thread designation and when the selected tap stage matches the manual tapping sequence.
The set covers the rougher, intermediate, and finisher stages for a controlled three stage manual tapping sequence. UNC identifies a Unified coarse inch thread used on inch based fasteners where a robust coarse thread series is required. The referenced thread standard is ANSI B 1.1. HSS-G indicates a ground high speed steel execution for accurate manual thread cutting in suitable materials. Check the prepared hole, holder, lubrication, and alignment before use in workshop repair, field service preparation, and controlled hand threading tasks.
- cutting or reworking internal UNC 1/4 x 20 LH threads where the drawing or mating part requires this exact designation
- The set covers the rougher, intermediate, and finisher stages for a controlled three stage manual tapping sequence.
- left hand thread work where the thread direction must not be confused with right hand standard threads
- selection by DIN 352 tool dimensions and the stated thread standard where applicable
- inch based fastener maintenance where the Unified thread series must match the existing part
- 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 Match UNC 1/4 x 20 LH, tap stage, thread direction, holder fit, and hole preparation before the tool enters the workpiece.
- HSS-G cutting material is stated in the product data and supports selection by material execution instead of appearance
- DIN 352 dimension reference helps you compare the tool with drawings, stock systems, and existing tool lists
- tolerance class 2B gives a clear selection reference for the internal thread requirement
- set structure keeps the required hand tap stages together for UNC 1/4 x 20 LH
- staged manual cutting reduces the need to force a single tap through the full thread profile
Drawbacks
- The product is only correct for UNC 1/4 x 20 LH and the stated tap stage; use another item from Threading tools if thread, direction, or stage differs.
- Confirm that the component requires UNC 1/4 x 20 LH and that thread direction matches the selected tool.
- Prepare the tapping hole and secure the workpiece so the tap can enter square to the surface.
- Select a suitable tap wrench or guided driving setup for the tap shank.
- Start with the rougher tap from the set and keep the tap square to the hole axis.
- Apply suitable cutting oil before the cutting edges engage the workpiece.
- Turn steadily and remove chips from the flutes at controlled intervals.
- Continue with the intermediate tap and then the finisher tap in sequence.
- Clean the thread and verify the result with the mating part or an appropriate inspection method.
- 1 set of 3 pieces Hand Tap set of 3 pieces DIN 352 HSS-G left hand thread - UNC 1/4 x 20 LH
- Product type: 3 piece hand tap set
- Standard: DIN 352
- Cutting material: HSS-G
- Thread system: Unified coarse inch thread
- Thread designation: UNC 1/4 x 20 LH
- Thread standard: ANSI B 1.1
- Tolerance class: 2B
- Thread direction: left hand
- Core hole diameter from product data: 5.2 mm
- Overall length L1: 50 mm
- Thread length L2: 19 mm
- Shank diameter D2: 6 mm
- Square k: 4.9 mm
- Packaging unit: 1
- Which exact thread is this product for?
- This product is for UNC 1/4 x 20 LH. UNC identifies a Unified coarse inch thread used on inch based fasteners where a robust coarse thread series is required. The referenced thread standard is ANSI B 1.1.
- Is this product for internal or external threads?
- This product is for internal threads. Use a round die when the workpiece needs an external thread.
- How do you choose the correct tap stage?
- Choose the stage by the manual tapping sequence. The set covers the rougher, intermediate, and finisher stages for a controlled three stage manual tapping sequence.
- What is important with left hand thread selection?
- Left hand selection is critical because UNC 1/4 x 20 LH must not be replaced by the equivalent right hand thread. Check the drawing, mating part, and tool marking before use.
- Where can you find technical background for hand taps?
- Use the Technical information hand taps as PDF.
- Can this product be used for repair or thread cleaning?
- Use it for re tapping or cleaning only when the existing internal thread is UNC 1/4 x 20 LH and the thread condition still allows controlled cutting.
- Where can you compare inch based thread references with metric workshop units?
- Use the Inch to mm conversion table as PDF.
- How do you avoid selecting the wrong inch thread series?
- Compare thread family, nominal size, pitch in threads per inch, and direction. Similar inch sizes from different thread systems are not interchangeable.
- Where can you find the matching VÖLKEL threading tool catalog?
- Use the VD 23 catalog as PDF.
Do you need help selecting or using the product?
Use the contact form.
In this category: Threading tools
