Technical Info

General data

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Nomenclature of Drill

Machining formula

Working of Main Angle

Point Angle Torsional Angle Lip Relief Angle  

Large → Tork → Small
Small → Thrust → Large

Bad → Cutting ability → Good
Good → Chip emission → Bad
Large → Tool toughness → Small

Small → Tool wear → Large
Small → Vibration → Large
Point Angle Torsional Angle Lip Relief Angle

• V : Cutting Speed
• D : Diameter of drill
• N : Revolution
• π : (3.14)

• f : Feed
• S : Depth of cut per min
• N : Revolution

• δ : Helix angle
• D : Diameter of drill
• L : lead
• π : (3.14)

Drill Trouble Shooting

Drill Trouble Shooting

Trouble issue Cause Solution
Drill does not enter the workpiece Shortage of Lip Relief.
Thick the Web.
Regrinding to Lip Relief properly.
Thin down the Web.
Margine chipping Excessive Jig busing . Using the suitable busing for Drill size.
Blance of cutting edge Overheating the drill on work. Reduce feed speed and supply with cutting oil sufficiently.
Chipping of cutting edge Excessive rake angle.
Excessive feed speed.
Modify for Lip Relief.
Reduce feed speed.
Broken of tang Imperfection of connect between Taper shank and socket Remove to socket alien substance or change to socket if it wear
Broken for brass work Improper choice for Drill shape
blockage the chip on groove point
Choice to Drill properly
Crack of Drill core Shortage of Flute Clearance.
over feed speed
Regrinding to Drill proper rake angle.
Reduce feed speed.
Over hole size Edge of flue angle and cutting length is different.
Main shaft is loose
Choice for good quality Drill.
Tight up the Main shaft properly.
Broken for Flute edge Over cutting speed
Hard alien substance on workpiece
Shortage of Drill tip
Wear to Drill
Grinding for tip properly.
Reduce feed speed.
Irregular chip size Edge of flue was wrong grinded or did work one side of flute. Need to regrinding accurately.
Choice for good quality drill.
Rough hole Edge of flute was grinded as blunt or improperly.
Unsupplied with cutting oil on Drill tip.
Over feed speed
Unsubstantial Tool holder.
Regrinding to edge of flute angle.
Supply with cutting oil properly.
Reduce feed speed.
Fix to Tool Holder solidly.