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The drilling process
A brief introduction
to the subject of deep hole gun drilling
In the machining world, drilling depths of 10 x D and dee- Typical procedure with all gun drills on
per are regarded as deep hole drilling operations, whereby conventional machine tools:
smaller drilling depths can naturally also be produced with • production of pilot hole (tol. H8). Enter at low revolutions,
gun drills. Advantage is taken of the positive side effects,
as for example good surface quality, low deviation from approx. 200 rev./min, feed rate approx. 500 mm/min.
concentricity and optimised alignment accuracy. • setting coolant pressure and speed.
• continuous drilling to complete hole depth
High pressure cooling -
has become a matter of course. without wood pecking.
In recent years, internal cooling has established itself for • switch off coolant supply
all drilling tools. Coolants are now living up to their name
and being supplied via coolant ducts to where they are after reaching hole depth.
urgently required. Considerable improvements in tool life • rapid withdrawal with stationary spindle.
and less breakages have been achieved by this measure
for twist drills, taps etc. Application advice
Every conventional machine tool currently on the market • For drilling depths in excess than 40 x D we recommend
can be supplied with high pressure internal cooling and is
therefore also suitable for deep hole drilling. the use of two or more gun drills, e. g. 10 x 400 mm
The share of gun drills on machining centres, lathes etc. is and 9.95 x 800 mm.
forever gaining more importance. The process is therefore • Gun drills for drilling depths of more than 40 x D should
increasing in popularity in the machining world. enter the pilot hole revolving in the left hand direction.
• For machining of long-chipping materials we recommend
All gun drills must have Deep hole drilling is not the use of gun drills with polished flutes.
support for the pilot hole. a closed book, but can be • Single-fluted gun drills for long-chipping aluminium
Gun drills must never ope- mastered by anybody as should be supplied with point grind 180° and coolant
rate at full speed without long as certain conditions chamber.
support in the machine are adhered to. • Generally we recommend the use of soluble oil with a
shop. Recommended cutting minimum oil content of 10 %.
rates for the application of
Guhring gun drills can be
found on the pages for the
individual types!
Deep hole drilling Deep hole drilling machines
on conventional machine tools
1. operation - pilot hole L=1,5xD
workpiece
+0,03
+0,01
D workpiece drilling bush holder spindle unit coolant cycle
workpiece drilling bush
coolant cycle clamping feed drive
2. operation - deep hole drilling
D
high pressure pump high pressure
pump
filter M filter
M
MM
4 Gun drills
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www.guhring-tools.ru
