CNC Small Bore Fine Boring Inserts Micro Adjustable Precision IT7 Internal Hole Machining Insert

Boring insert for small-diameter finishing. Tested on a 4140 bore at HRC28, 200 m/min, 0.08 mm/rev. Got plus-minus 0.005 mm tolerance on a 20 mm bore. Surface finish Ra 0.4. Edge geometry is precise. 5 stars.

Insert for boring bar operations. We use these on 4140/4340 ID work at HRC28. Consistent geometry, sharp edge, good chip control. Worked as advertised. 5 stars.

Small-diameter boring insert. Tested on a hardened 4140 bore at HRC32. Got plus-minus 0.005 mm and a clean Ra 0.2 finish in one finishing pass. Good chip-breaker geometry. 5 stars.

Precision boring insert for ID turning. Cutting 17-4 PH at HRC30, 180 m/min, 0.06 mm/rev. Bore tolerance plus-minus 0.005 mm, surface finish Ra 0.2. Excellent for finish-boring. 5 stars.

Boring insert — tested on an aluminum housing bore at 400 m/min, 0.1 mm/rev. Surface finish Ra 0.4, plus-minus 0.01 mm tolerance. Sharp out of the box. 5 stars.