... tolerances and controlled straightness.4. Down the hole hammers and DTH button bits (Down The Hole Drilling)Offer ir hammers,DHD3.5,DHD340a ... ,DHD360,DHD380,and low pressure hammers CIR65a, CIR90, CIR110, CIR150,CIR170etc,DTH drill bits ... .4mm, 25mm,30mm,33mm,38mm,etc.8. Blast furnace tap hole drill tools.(Rod, Cross type bits, button bits and X type ...