About Gun Drill Processing
　　Depth gun drill is also called depth drill, it was initially used for weapon manufacturing industry, and thus it got the name of gun drill. With continuous development of science and technology and continuous efforts of the deep hole processing system manufacturer, deep hole processing has become a convenient and high-efficiency processing way, and is extensively utilized for such fields as automobile industry, spaceflight industry, structure and construction industry, medical apparatus industry, mould, cutting tool, jig, oil pressure, air pressure industry and so on.
　　Gun drill is the ideal deep hole processing resolution. With gun drill, it can obtain the precise processing effect. The processed hole has precise position and high straightness accuracy and axiality, and it also has very high surface fineness and minor deviation. It can conveniently process different forms of deep holes. In actual application, it can substitute the process of drilling and reaming with the once processing, and it has very strong process reliability.
　　The gun drill can drill and cut cast iron, carbon steel, copper, aluminum alloy, alloy steel and so on. It can complete hole drilling, boring and reaming once. With once cutting feed, it can process the hole with high accuracy (class IT8-11), high straightness accuracy (0.16-0.5mm/1000mm) and low roughness (Ra6.3-Ra0.8). The drilling and cutting linear speed can reach above 30-100mm/min.
　　The gun drill is mainly used for drilling and cutting the diameter of small holes, the diameter ranges from 1.5mm to 38mm. The length-to-diameter factor of the hole drilling refers to: drill bit diameter x 150 (namely the maximum drilling depth). Via the main shaft and drill bit center, the high-pressure cooling liquid reaches the cutting position. Scrap iron is discharged via V-type groove at the drill bit.

Operating instructions for the gun drill
　　1. In utilization, it must select the guide sleeve of the suitable size. The clearance between the guide sleeve and the gun drill head must keep within 0.003mm--0.008mm. The main shaft of the machine tool that uses the gun drill must have the fairly higher axial and radial rigidity, and the guide sleeve and the main shaft shall have fairly higher axiality. In hole drilling, for the processed material (especially the casting), there shall not be breakage, air hole and other foreign matter at the hole drilling position, otherwise it may lead to tipping, even head falling. In operation, it shall correctly select the cutting amount. Generally, the cutting speed: V=1.1-1.65m/s; amount of feed: s=0.015-0.03mm/rotation; oil pressure: P=2.5-6.0Mpa; flow rate: Q=0.2-0.65L/s.
　　2. The cutting liquid used for the gun drill is also very important, and it can directly affect the precision of the processed hole, and it must select the special-purpose gun drill oil. Generally, the cutting liquid used for the gun drill shall have the extreme pressure additive to ensure to form the oil film at high pressure and prevent dry grinding. The viscosity of the cutting liquid is related to the drilled hole diameter. If the diameter is smaller, the viscosity will be lower. Compared with the ordinary mechanical working, the cutting oil sent to the cutting area of the gun drill has such characteristics as high pressure, great flow rate and high filtration precision. The flow rate shall increase with the increase of the hole depth to ensure that the cutting oil has larger flow speed and achieve the purpose of discharging the scraps smoothly.
　　3. After gun drill bit is worn, it needs to grind the edge in time and correctly. For edge grinding, at the universal cutting tool grinding machine or special-purpose cutting tool grinding machine, it must mount the gun drill at the special-purpose clamp for edge grinding. The resin diamond grinding wheel whose granularity is about 120 can be selected for edge grinding. For each edge grinding, it shall only thin the rear edge face of the internal angle and external angle. It must ensure the correct geometrical angle (this Company will provide drawings) and tip position.
About BTA
　　BTA hole drilling manner is different from gun drill for its manners of cooling liquid entering and scrap iron discharging. For BTA, oil feeder brings the cutting oil to the cutting position, and then the cutting oil brings the scrap iron into the holes in the drill bit and drill rod for discharging the scrap iron. For drilling the larger hole (above 40mm), BTA hole drilling manner will be the first choice.

Application mode of the BTA machine tool

Hole drilling (diameter range: 30mm-120mm )	Hole boring (diameter range: 35mm-1200mm )
Ejector drilling head (special machine tool)	Boring drill (special machine tool)
Jacking	Scraping and roll
Bottom isomerism	Bottle boring