Liaocheng Jinquan Construction Machinery Co.,Ltd is selling this:

Other Hard Rock Mining Integral Drill Steel Rod 22X108mm

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The main material of hex integral drill steel rod is 55SiMnMo.
Intergral Drill Steel are normally produces from 19mm(3/4”),22mm(7/8”) or 25mm(1”) Hexagon Drill Steel,where the dimension given are measured across the flat of the hexagon.
Integral Drill Steels are a fixed length with a shank at one end and a bit at the other ,and are able to drill to a depth equivalent to their effective length.The bit may consist of single chisel shaped tungsten carbide insert or three such inserts.
To drill deep holes,the rods are designed to be used in a series where the lengh of any rod used in longer than the one used just before it.
To do this, a series of rods must be produced so that the bit diameter is reduced for each increase in lengh if rod to prevent jamming of the bit in the hole.