NUTOOL NBD350 - Page 31

31
GB
GENERAL GUIDELINES FOR DRILLING
Alwayscentrepunchthepositionfordrilling.Acentrepunchis
a pointed tool that marks the material to be drilled with a small
indent.Itstopsthedrillbitmovingfromthedesiredposition.
Always start by drilling a small pilot hole and gradually
progressin drill diameter.When drilling metal,lubricate the
drilltipwithoil.
NEVERcoolwithwaterorwaterbasedlubricantotherwisean
electricshockcouldoccur.DONOTuseoilwhendrillingcopper
orbrass.Careshouldbetakenwhendrillingcopperandbrass
asthedrillbitwillbepronetojamming.
Small diameter drills require a higher speed and as the drill
diameterincreasestheslowerthespeedrequired.
The following drilling speed chart is a guide only and only covers
themorecommonmaterials,drilldiametersandspeeds.
DrillingSpeedChart(GuideOnly)
Material to be drilled
D E F G H I
C Drill Speed (RPM)
3 2500 2500 2500 2500 2500 2500
4 2500 2500 2500 2500 2500 2500
5 1750 2500 2500 2500 2500 2500
6 1750 2500 2500 2500 2500 2500
7 1250 1750 2500 2500 2500 2500
8 1250 1750 2500 2500 2500 2500
9 900 1250 1750 2500 2500 2500
10 900 1250 1750 1750 2500 2500
11 600 900 1250 1750 1750 2500
12 600 900 1250 1250 1750 1750
13 600 600 900 1250 1250 1750
C Drill Dia mm
D Steel
E Cast Iron
F Gun Metal
G Aluminium
H Plastics
I Wood