TIPS, IDEAS ON DRILLING
Chips clogging flutes is the major cause of
When hole depth is grater than three diameters, consider it a deep hole.
"Peck" drilling is required to remove chips when drilling deep holes.
Feed rate is the major controlling factor in breaking up chips.
A split-point or a thinned web will reduce thrust on the drill.
Tool design (chipbreaker) can help control the breaking of chips.
Coolant helps wash away chips and prevents tool and work from overheating.
THE CAUSE, AND CORRECT IT:
Work must be adequately supported and held.
The tool must be amply rigid to withstand heavy feeds without twisting; use the
shortest tool possible.
Spindle must have capacity to supply steady power to a multidrill unit.
The entire machine must resist deflection under working load.
The fixture should be rigid enough to withstand the work forces.
Practically all holes 0.050" or smaller
are in the deep-hole category.
Webs of small drills are proportionately thicker than larger drills.
Lip relief angle should be greater on small drills.
Avoid the tendency to overspeed and underfeed drills, they must produce chips,
Peck drill just enough to prevent packing chips in the flutes.
Decrease speeds and feeds as holes get deeper: