Tap Troubleshooting
EMUGE Taps are very free cutting and will easily cut oversize threads if overfed or pushed. For the best results, we recommend the use of an EMUGE Quick-Change Tap Holder with built-in tension, compression and overload clutch features. Always utilize your holder's tension feature by programming spindle feed to 95-98% of the calculated feed rate.
| Problem: Tapping oversized threads (no-go gage too loose) | |
| Possible Cause | Possible Remedy |
|---|---|
| Improper tap for material and thread application. | · Use a suitable tap for the hole style and material being tapped. Reference the EMUGE Tap Finder for proper selection. |
| Cutting speed to high. | · Reduce cutting speed. · Improve coolant/lubrication. |
| Cold welding on the flanks of the tap (loading). | · Use a new tool. · Use surface treated taps. · Improve coolant/lubrication. · Grind away chipped and damaged teeth. |
| Chip packing in flutes. | · Use tap with different flute geometry/angle. · Possibly use set of taps. |
| Grinding burr. | · Remove burr with soft wire or fiber brush. |
| Incorrect fixturing or positioning of part. | · Use tap holders with axial and parallel floating. · Check clamping of part for correct alignment. |
| Inconsistent feed of tap. | · Tap with controlled feed. · Check CNC programs. · Check lead screw for backlash. · Use compensating tension/compression tap holder. |
| Problem: Tapping oversized threads (no-go gage loose) | |
| Possible Cause | Possible Remedy |
| Tap selected too large for class of thread fit required. | · Review markings on tap and determine if it is suitable for the class of fit required. · If in doubt, contact an EMUGE Representative. |
| Improper reconditioning of tap. | · Reconditioning of tap requires that all ground surfaces maintain the original geometry put on by the manufacturer. · Contact an EMUGE Representative for instructive information. |
| Problem: Tapping bellmouthed hole (first few threads gage oversize) | |
| Possible Cause | Possible Remedy |
| Wrong initial starting pressure. | · Work with controlled tap feed. |
| Axially hard working spindle. | · Use a tap holder with length compensation. |
| Incorrect fixturing or positioning of part. | · Use a tap holder with axial and parallel floating. · Check clamping of part for correct alignment. |
| Problem: Torn and rough threads | |
| Possible Cause | Possible Remedy |
| Improper selection of tap for material and thread application. | · Use a suitable tap for the hole style and material being tapped. Reference the EMUGE Tap Finder for proper selection. |
| Cutting speed too fast or slow. | · Select proper cutting speed. · Improve coolant selection to assist the effects of tap speed. |
| Cold welding on the flanks of the tap (loading). | · Use a new tool. · Use surface treated taps. · Improve coolant/ lubrication. · Find away chipped and damaged teeth. |
| Chips packing in flutes. | · Use tap with different flute geometry/angle. · Use set of taps. |
| Grinding burr. | · Remove burr with soft wire or brush. |
| Tap drill too small. | · Use correct size drill. · Reference recommended sizes listed in EMUGE catalog. Note that cutting and roll form taps use different size tap drills for the same size thread. · If in doubt, contact an EMUGE Representative. |
| Insufficient coolant/ lubrication. | · Selection of suitable coolant/lubrication for material being tapped. · Use adequate amounts of coolant lubrication. |
| Tool overloading due to coarse pitch, hard materials or short chamfers. | · Use a set of taps. |
| Problem: Tapping undersized threads (go gage won't enter/binds up part way into hole) | |
| Possible Cause | Possible Remedy |
| Tap selected too small to do multiple regrinds. | · Limit the number of regrinds a tap has. · Use a new tap. |
| Area of wear not removed when tap was resharpened. | · Grind tap again. · Use a new tap. |
| Improper tap for material and thread application. | · Use suitable tap for the hole style and material being tapped. · Reference the EMUGE Tap Finder for proper selection. |
| Go gage binds up part way into hole. | · Tap is dull - recondition or replace tap. · Avoid too much axial force during tapping operation (this caused the tap to cut out of lead) · Use tap holders with length compensation. |
| Tap selected too small for class of thread fit required. | · Review markings on tap and determine if it is suitable for class of fit required. · If in doubt, contact an EMUGE Representative. |
| Problem: Tap life too low | |
| Possible Cause | Possible Remedy |
| All reasons stated in torn and rough threads. | · See torn and rough threads. |
| Loss of tap hardness by excess hear during regrinding. | · Change the specification of the grinding wheel. · Use coolant while grinding. |
| Loss of surface treatment from regrinding. | · Retreatment of the tap surface. · Check suitability of surface treatment for material being tapped. |
| Work hardened drill hole and hole chamfer. | · Change or regrind tap drill more frequently. · Check proper drilling speed and feed. · Anneal part before tapping. |
| Problem: Torn and rough threads | |
| Possible Cause | Possible Remedy |
| Improper selection of tap for material and threading application. | · Use a suitable tap for the hole style and material being tapped. · Reference the EMUGE Tap Finder for proper selection. |
| Tap drill too small. | · Use correct size drill. Recommended size drills listed in EMUGE catalog. Note that cutting and roll form taps use different size tap drills for same size thread. · If in doubt, contact an EMUGE Representative. |
| Tap hole not deep enough. | · Check actual drill depth, drill may have slipped back into holder. |
| Missing tap drill hole. | · Ensure tap drill hole is present. Common problem in multiple spindle applications on transfer lines. |
| Chips packing in flutes. | · Use tap with different flute geometry/angle. · Use a set of taps. |
| Cutting speed too high or low. | · Select proper cutting speed. · Improve coolant/lubrication to assist the effects of the tap speed. |
| Cold welding on the flanks of the tap (loading). | · Use a new tool. · Use surface treated taps. · Improve coolant/lubrication. · Grind away chipped and damaged teeth. |
| Overload of the chamfer teeth. | · Use longer chamfer. · Increase number of tap flutes to provide more chamfered teeth. |
| Incorrect fixturing or positioning of part. | · Use tap holders with axial/parallel floating. · Check clamping of part for correct alignment. |
| Tap hitting the bottom of hole. | · Use tap holder with length compensation and torque overload system. |
| Tapping hard or high tensile materials. | · Check selection of tap, carbide tap may be more suitable then high speed steel taps. |
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