Owner's manual

2-3 x dm

5 x dm

5-7 x dm

2. Applications – Thread turnin

Boring bar type Max. overhang

Steel

Steel dampened

Carbide

Internal thread turning

Internal threading is more demanding than external threading, due

to the increased need to evacuate chips effectively.

Chip evacuation, especially in blind holes, is helped by using left-

hand tools for right-hand threads and vice versa (pull-threading).

However, this also creates the greatest risk of insert movement.

Modi ed  ank infeed should always be used to generate a spiral

chip, which is easy to guide towards the entry of the bore

Boring bar selection also has a strong in uence on the effective-

ness of internal threading. Three main bar types can be used for

internal threading, depending on the length of overhang and level of

stability required.

• Steel boring bars - maximum 2-3 x bore diameter overhang

• Steel dampened boring bars - maximum 5 x bore diameter over-

hang

• Carbide boring bars - maximum 5-7 x bore diameter overhang

Boring bar de ection is in uenced by the boring bar material,

diameter, overhang and cutting forces. The recommended clamping

length in a boring bar holder with a sleeve is 4 x bar diameter dm