Thank you for 100% supporting TDC core bits.
I asked factory to check again, and confirm 661075 is made by TDC in 2005 ---
Sorry we are not aware of it immediately, because our database can track production record within 10 years only.
As our observation report dated 9-Mar, the issue is because of thickness
thickness of segment : 5mm( new) vs. 4.8mm( normal size after use) vs. 3.8 mm( issue one from your side)
thickness of wall of core bit( steel part) : 3mm( normal ) vs. 1.5mm ( issue one from your side)
As you know, if customer uses normally , wall of core bit ( steel part) would also wear off graduately, but normally, life of segment would end first.
( because it's DIAMOND segments cut the concrete, not steel part)
so why the thickness of steel part wore out quickly ? bad run-out may be the reason.
our suggestion to prevent the same problem:
please ask client to settle core-bit on machine properly.
also, please check the run-out of the drilling machine.