Deep hole drilling
Requirement deep hole drilling
For good hole drilling results, cooling, lubrication and high-pressure coolant systems are required. Single flue gundrilling cannot only be achieved on deep drilling machines but is also very good on machining centers (drilling, turning and milling center) with:
- Deep-hole drilling oil,
- Emulsion (min. 10 – 12 % concentration, with additives),
- and under conditions, with a minimum quantity air/lubrication system
The asymmetric goemetry single-edged single flute gundrill is nit self-starting, therefore a pilot hole or drill bushing is required.
The prevent outbreaks during retraction of single flute gundrill we recommend plunging in counterclockwise rotation.
Too big a diameter difference between the tool and drill bush or pilot hole can cause the following problems:
- poor hole quality
- excessive hole straightness deviation
- drill breakage
Recommendation: Bushes DIN 179A medium.
Drill bushing has a form set against the workpiece!
Recommendation: pilot drill with m7 tolerance.
Deep drilling machine
- Make a pilot hole
- Enter with stationary spindle or speed < 50 rpm
- Set coolant pressure, speed and feed
- Continuous drilling to depth without peck
- Switch off coolant supply after reaching hole depth
- Retraction with stationary spindle or < 50 rpm
Failure to comply may result in tool breakage.
Special nose grinds
In the following examples, various forms are shown:
Please contact us if you need a special grind for your tools.
The information below are average values as a guide. They depend on meterial, bore diameter, unsupported tool length, cooling lubricant, drilling conditions ans stability of the machine.
Summary table Typ 100, Typ 110, Typ 120
Feed should be reduced at start, exit and cross holes.