Maker : Guhring

Troubleshooting - Application problems with new taps

Thread produced is too large

• incorrect tap, tap geometry not suitable for the application
  ⇒ apply correct tap for the material to be machined
• tapping size hole too small
  ⇒ observe tapping size hole table in the technical selection.
  Note different tapping size hole diameters for fluteless taps.
• alignment error of tapping size hole or position
  ⇒ check for correct tool clamping
  ⇒ apply floating tap holder
  ⇒ check core drill
• machine spindle axially restricted
  ⇒ use mechanical feed
  ⇒ apply tension/compression tap chuck
• cold welding at the flank of the tap
  ⇒ apply new tap
  ⇒ apply coated tap
  ⇒ optimize lubrication
• lead of tap unsatisfactory due to insufficient thread depth
  ⇒ tap with forced feed
  ⇒ apply tap with modified lead
• cutting speed too high
  ⇒ reduce cutting speed
  ⇒ improve lubrication
• lubrication or coolant supply insufficient
  ⇒ ensure sufficient and suitable coolant supply and check concentration
• tolerance specification on tap does not correspond to specifications on drawing and/or thread gauge
  ⇒ apply correct tap for required tolerances

Thread axially miscut

• spiral-fluted taps, corresponding to our design,are applied with too much pressure for initial tapping
  ⇒ with spiral-fluted taps only light pressure required for initial tapping.
  The tap should immediately be applied within the tension/compression range
• initial tapping pressure too low for taps with spiral point corresponding to our form "B"
  ⇒ taps with spiral point or left hand spiral require higher axial pressure.
  Ensure tap operates within the tension/compression range

Thread produced is too small

• tolerance specification on tap does not correspond to specifications on drawing and/or thread gauge
  ⇒ apply correct tap for required tolerance
• incorrect tap ⇒ apply correct tap for the material to be machined
• tap does not cut accurately (thread plug gauge)
  ⇒ avoid strong axial forces during the cutting process
• machine spindle is axially too rigid
  ⇒ apply tension/compression chuck

Thread surface not according to requirements

• cutting edge geometry not suitable for the application
  ⇒ apply "correct" tap for the material to be machined
• cutting speed too high
  ⇒ reduce cutting speed
  ⇒ optimize lubrication
• insufficient coolant (concentration and supply)
  ⇒ ensure suitable coolant and sufficient volume
• chip congestion ⇒ apply suitable tap type
• tapping size hole too small
  ⇒ observe tapping size hole diameter specifications to DIN 336 or respective standards. Observe table for fluteless taps
• with tough, hard materials loading on tool too much or pitch too steep
  ⇒ apply hand tap sets
• built-up edge ⇒ apply coated tap
• cold welding ⇒ improve coolant supply

Tool life insufficient

• surface hardening of tapping size hole
  ⇒ check drill (cutting edge) for wear
  ⇒ heat or surface treatment following thread production
• reasons listed under : "thread surface not according to requirements"
  ⇒ reasons listed under : thread surface "not according to requirements"
• chip congestion
  ⇒ apply correct tap

Tool breakage during advance or return

• tapping size hole too small
  ⇒ observe tapping size hole dia. acc. to DIN 336 or respective standards
• teeth of chamfer lead overloaded
  ⇒ longer chamfer lead (blind or through hole)
  ⇒ increase no. of teeth of chamfer lead by increasing no. of flutes
  ⇒ apply tap sets
• tap hits bottom of tapping size hole
  ⇒ check hole depth
  ⇒ apply tension/compression tap chuck
• lack of or incorrect chamfer of tapping size hole, positional or angle error of tapping size hole
  ⇒ correct chamfer angle of tapping size hole
  ⇒ ensure correct tool clamping
  ⇒ apply floating tap holder
  ⇒ check core drill
• tool hardness not suitable for the application, cutting edge geometry not suitable for the application
  ⇒ apply suitable tap for the individual application

Thread produced is too large

• burrs
  ⇒ remove burrs
• cutting edge geometry (chamfer lead, rake-, chamfer-, spiral point angle) not retained
  ⇒ observe technical specifications when regrinding.
  ⇒ observe regrinding instruction.

Thread produced is too small

• worn section has not been reground correctly
  ⇒ regrind again or apply new tool. Observe max. regrinding limits.
• tap too small due to no. of regrinds
  ⇒ max. regrinding limit reached. apply new tap

Thread produced not according to requirements

• burrs
  ⇒ remove burrs
• cutting edge geometry (chamfer lead, rake-, chamfer-, spiral point angle) not retained
  ⇒ observe technical specifications when regrinding.
  ⇒ observe regrinding instruction
• peak-to-valley height of the reground tap too large
  ⇒ regrind again or apply new tool. Observe max. regrinding limits.
• cold welding at the flanks
  ⇒ remove cold welding marks

Tool life insufficient

• cutting edge geometry (chamfer lead, rake-, chamfer-, spiral point angle) not retained
  ⇒ regrind again or apply new tool. Observe max. regrinding limits.
• loss of tap hardness due to heat development during the regrinding process
  ⇒ check quality of grinding wheel
  ⇒ check coolant supply
• loss of coating
  ⇒ recoat
  ⇒ check coating of the material to be machined