Blast Furnace Tapping hole bits

we offer H25, R28.5,R32,B32,T38 Thread tap drill bits from 32mm-152mm,coupling,adaptor and Rod etc.
H25 thread :Cross bits and X typebits:diameter:32mm-152mm:
H25-R32 Tap hole rod.Lenth:2000mm-5000mm
R32 Cross bits 45mm-152mm, 
 Drill rods with thread copper welded Tunsgten Carbide bits 
For very difficult tap holes with hard clays and some inclusions of slag and iron.It is made of a high alloy steel with cooper welded tungsten carbide point tips. 
size: 43mm-120mm diameter.