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close this bookCentring, Drilling and Counterboring / Countersinking - Course: Techniques for Machining of Material. Instruction Examples for Practical Vocational Training
View the document(introduction...)
View the documentPreface
View the documentInstruction example 3.1.: Shaft
View the documentInstruction example 3.2.: Die plate
View the documentInstruction example 3.3.: Adapter
View the documentInstruction example 3.4.: Draw-in bush

Instruction example 3.2.: Die plate

This example serves to practise centring with the turning tool on rotationally symmetrical parts held in a chuck



100 Cr 6 (100 = 1 % carbon; Cr 6 = 1.5 % chromium)


dia. 32×47

Cutting and operating tools

Inside turning tool for corner work, key

Measuring and testing tools

Vernier caliper, dial gauge, protractor


Stepped chuck jaws which can be turned out, supporting plates, coolant, Vee (for round cross section of turning tool shaft)

Required previous knowledge

Reading of drawings, measuring and testing, scribing and prick-punching

Explanations to the working drawing

­(0.04) = admissible true-running error of 0.04 mm not to be exceeded.

Surface finish: finished Rz 20

Sequence of operations


1. Dimensional inspection

2. Clamping of workpiece

Type of clamping: "chucking" in stepped chuck jaws which can be turned out. Chuck on dia. 30, measure on dia. 20, maintain admissible deviation. Check for true running. If necessary, turn out chuck jaws. Interrupted cut! Wear safety goggles I

3. Clamping of tool

Clamp short. See to necessary clearance angle. Swivel top slide by 30 degrees.

4. Setting of cutting values

5. Tool to take first cut

Set end stop. Let tool take first cut at interedge between end face and surface of hole by means of top slide adjustment.

6. Centring

Adjust cross slide to the left. Manually finish-turn centre hole by top slide adjustment. Use coolant for tools without carbide tips.

7. Dimensional and surface inspection

8. Unloading