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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 3.3.: Adapter

This example serves to practise drilling with the drill and boring with the boring tool on rotationally symmetrical parts held in a chuck.



St 60-2 (St = steel, 60 = 600 MPa tensile strength, 2 = grade)


dia. 55×70

Cutting and operating tools

Drill dia. 20. internal roughing tool, centre drill A 3.15, right-hand side-cutting tool, key.

Measuring and testing tools

Vernier caliper, depth gauge, dial gauge


Drill chuck, taper sleeves, supporting plates, coolant, block gauge 25 mm, chuck jaws which can be turned out

Required previous knowledge

Reading of drawings, measuring and testing, scribing and prick-punching, drilling and counterboring/countersinking

Explanations to the working drawing

ø 32-0.1 means:

toleranced size


upper deviation


lower deviation


Surface finish: finished Rz 20

Sequence of operations


1. Dimensional inspection

2. Clamping of workpiece

Type of clamping: "chucking" in chuck jaws which can be turned out. Clamp short.

3. Centring

4. Longitudinal turning and facing

Set live centre.

5. Clamping of tool

Drill to be held in tailstock. Ensure firm fit of taper.
Clamp short considering blind hole length. (Use vee, if necessary).

6. Drilling ø 20

Drill through hole dia. 20 by manual adjustment of tail-stock sleeve. Use sleeve scale.

7. Boring ø 32-0.1

Make sure the drill edge is sufficiently cooled. Set end stop. Insert block gauge 25 mm. Tool nose to take first cut on transition between end face and inner surface of the workpiece. Remove block gauge. Set feed
Finish-bore ø 32-0.1
Utilize "0" position of cross-slide.

8. Deburring

Use primary cutting edge.

9. Re-chucking

10. Facing to 60 mm length

11. Deburring

Thoroughly deburr inner and outer edges.

For batch production repeat sequence of operations until operation 3, re-chuck, centre and continue with operation 4. Operation 8 is then deleted (earlier operation).