It’s the main innovation the BTA system brings in the braoching machinig of keyways with CNC machine tools without Y axis.

Thanks to its graduated scale ingraved in the collar it’s possible to correctevery simmetry mistake may be occured during the keyway machinig. Thanks to the shift of the inside hole as to the bush central axis (0,5 mm) the insert holder field of action goes from +0,5 m mto -0,5 mm.

Every notch on the graduated scale corresponds to a 0,03 mm turn of the insert. The bush is made in hardned steel for tools and grinded. The available outside diameters fo the bush are: 32 mm, 40 mm and 50 mm (with H7 tolerance).

By Customer’s request BRIGHETTI MECCANICA SRL can supply this bush with a VDI connection or sizes in inches.

This adjustable graduated bush is covered by regular patent.

To help finding the correct tools for a machining, let’s make the example of a 4 mm keyway, 35 mm long with a H7 tolerance:

> Insert with L1=4; the code is IN-4-H7

> Insert holder: the code is UT-4-32 or UT-4-25 if the eccentric bush is necessary:

> The code for the bush is B-40 or B-32 respectively