​80 Internal Thread Processing Tips to Help You Easily Deal with Processing Problems!

Enlargement of the Internal Thread Pitch Diameter

• Use taps with appropriate accuracy grades.
• Increase the length of the engagement portion.
• Reduce the rake angle.
• Select a tap with a concentric wide back.
• Adjust the back angle of the cutting taper length.

• Use a front tap or spiral tap.
• Reduce the number of tap grooves and increase the groove volume.
• Use fine pitch threads.
• Increase the bottom hole diameter as much as possible.
• For blind holes, deepen the bottom hole as much as possible.
• Shorten the tapping length.
• Use other cutting oils and oiling methods.
• Use internal coolant taps.

• Adjust the cutting speed.
• Prevent the tap from being eccentric or tilted with the bottom hole.
• Use a floating clamping method.
• Control the feed speed to prevent the thread crest from deforming.
• Use a forced feed method (pitch feed method).
• Choose the appropriate tapping machine processing capacity.
• Prevent spindle vibration.
• Use flexible tapping fixtures.

• Use taps with oxide film treatment on the surface.
• Use cutting oil with stronger anti-adhesion properties.
• Reduce cutting speed.
• Adjust the cutting angle to adapt to the material being processed.
• Use internal coolant taps.
• Shorten the thread processing length.

Reduced Internal Thread Diameter

• Use larger taps:
• For materials such as copper alloys, aluminum alloys, and cast iron, the expansion rate is small when tapping.
• Pay special attention to materials that are prone to rebound, such as tubular or thin plates.
• Adjust the clearance angle.
• Increase the cutting angle.
• Increase the rake angle.
• Increase the number of grooves.

• When rotating and pushing out, especially when the tap leaves the internal thread mouth, the speed should be appropriate to avoid damaging the thread.

• Improve the sharpness of the tap and reduce the residual whisker-like chips.
• After completely removing the residual chips, check the internal thread with a gauge.

• Increase the length of the front-end engagement.
• Adjust the cutting angle to suit the workpiece material.

Problems with the Internal Thread Processing Surface

• Use a tap with a clearance angle on the thread.
• Reduce the blade thickness.
• Use a tap with a surface treatment.
• Change the type of cutting oil and the oiling method.
• Reduce the cutting speed.

• Use a front-end tap or a spiral tap.
• Increase the bottom hole diameter.

• Reduce the cutting angle.
• Grind down the thread clearance angle.

• Avoid the blade thickness being too small.
• Do not grind the groove bottom.

Tap Breakage

• Change the material from SKS2 to SKH.
• Prevent chip clogging (use a front-end tap, spiral tap, or grooveless tap).
• Enlarge the chip groove.
• Clear the chips around the bottom hole and the workpiece.
• Make sure there is enough space for chip removal.

• Try to increase the bottom hole diameter.
• Shorten the tapping length.
• Use fine pitch threads.
• Increase the cutting angle to improve the sharpness of the tap.
• Slightly increase the thread clearance angle and reduce the blade thickness.
• Use a spiral tap.

• Reduce the cutting speed.
• Prevent the tap from being eccentric or tilted with the bottom hole.
• Use a floating clamping method.
• Use an adjustable tapping clamp.
• Prevent the tap from hitting the bottom of the blind hole.
• Prevent the bottom hole from being hardened.
• Maintain a stable feed rate.
• Remove chips from the previous process.
• Check the hardness and uniformity of the material being processed.

• Do not grind the groove bottom.
• Avoid too small a blade thickness.
• Grind away the worn part.
• Grind in advance.

Blade Chipping

• Reduce the cutting angle.
• Change the tap material.
• Reduce the hardness.
• Increase the length of the engagement portion.
• Prevent chip clogging (use a spiral groove tap).
• Shorten the thread length.
• Remove the worn part.
• Avoid too small blade thickness.

• Reduce the cutting speed.
• Prevent center deviation and imbalance when cutting.
• Do not turn rapidly when cutting blind holes.
• Increase the length of the cutting part.
• Use a flexible tapping fixture.
• Improve coaxiality.
• Prevent hardening of the bottom hole.