Threading Technology – Clamping Technology 520

161 Machine Taps UNC UNF UNEF UN-8 M MF NPSF Rp (BSPP) G NPT NPTF Rc (BSPT) STI SELF-LOCK Accessories NPSM/NPSC Tech. Info v c Product Finder 1.19 Troubleshooting guide for tapping Problem: Tapping oversized threads (no-go gage too loose) Possible Cause Possible Remedy ■ Improper tap for material and thread application. ■ Cutting speed to high. ■ Cold welding on the flanks of the tap (loading). ■ Chip packing in flutes. ■ Grinding burr. ■ Incorrect fixturing or positioning of part. ■ Inconsistent feed of tap. · Use a suitable tap for the hole style and material being tapped. Reference the EMUGE Tap Finder for proper selection. · Reduce cutting speed. · Improve coolant/lubrication. · Use a new tool. · Use surface treated taps. · Improve coolant/lubrication. · Grind away chipped and damaged teeth. · Use tap with different flute geometry/angle. · Possibly use set of taps. · Remove burr with soft wire or fiber brush. · Use tap holders with axial and parallel floating. · Check clamping of part for correct alignment. · 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. ■ Improper reconditioning of tap. · Review markings on tap and determine if it is suitable for the class of fit required. · If in doubt, contact an EMUGE Representative. · Reconditioning of tap requires that all ground surfaces maintain the orginal 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. ■ Axially hard working spindle. ■ Incorrect fixturing or positioning of part. · Work with controlled tap feed. · Use a tap holder with length compensation. · Use a tap holder with axial and parallel floating. · Check clamping of part for correct alignment. 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. Call an EMUGE Representative at 800-323-3013 if you need assistance. Problem: Torn and rough threads Possible Cause Possible Remedy ■ Improper selection of tap for material and thread application. ■ Cutting speed too fast or slow. ■ Cold welding on the flanks of the tap (loading). ■ Chips packing in flutes. ■ Grinding burr. ■ Tap drill too small. ■ Insufficient coolant/ lubrication. ■ Tool overloading due to coarse pitch, hard materials or short chamfers. · Use a suitable tap for the hole style and material being tapped. Reference the EMUGE Tap Finder for proper selection. · Select proper cutting speed. · Improve coolant selection to assist the effects of tap speed. · Use a new tool. · Use surface treated taps. · Improve coolant/lubrication. · Find away chipped and damaged teeth. · Use tap with different flute geometry/angle. · Use set of taps. · Remove burr with soft wire or brush. · 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. · Selection of suitable coolant/lubrication for material being tapped. · Use adequate amounts of coolant/lubrication. · 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. ■ Area of wear not removed when tap was resharpened. ■ Improper tap for material and thread application. ■ Go gage binds up part way into hole. ■ Tap selected too small for class of thread fit required. · Limit the number of regrinds a tap has. · Use a new tap. · Grind tap again. · Use a new tap. · Use suitable tap for the hole style and material being tapped. · Reference the EMUGE Tap Finder for proper selection. · 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. · 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. ■ Loss of tap hardness by excess hear during regrinding. ■ Loss of surface treatment from regrinding. ■ Work hardened drill hole and hole chamfer. · See torn and rough threads. · Change the specification of the grinding wheel. · Use coolant while grinding. · Retreatment of the tap surface. · Check suitability of surface treatment for material being tapped. · Change or regrind tap drill more frequently. · Check proper drilling speed and feed. · Anneal part before tapping. Problem: Tap breakage Possible Cause Possible Remedy ■ Improper selection of tap for material and threading application. ■ Tap drill too small. ■ Tap hole not deep enough. ■ Missing tap drill hole. ■ Chips packing in flutes. ■ Cutting speed too high or low. ■ Cold welding on the flanks of the tap (loading). ■ Overload of the chamfer teeth. ■ Incorrect fixturing or positioning of part. ■ Tap hitting the bottom of hole. ■ Tapping hard or high tensile materials. · Use a suitable tap for the hole style and material being tapped. · Reference the EMUGE Tap Finder for proper selection. · 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. · Check actual drill depth, drill may have slipped back into holder. · Ensure tap drill hole is present. Common problem in multiple spindle applications on transfer lines. · Use tap with different flute geometry/angle. · Use a set of taps. · Select proper cutting speed. · Improve coolant/lubrication to assist the effects of the tap speed. · Use a new tool. · Use surface treated taps. · Improve coolant/lubrication. · Grind away chipped and damaged teeth. · Use longer chamfer. · Increase number of tap flutes to provide more chamfered teeth. · Use tap holders with axial/parallel floating. · Check clamping of part for correct alignment. · Use tap holder with length compensation and torque overload system. · Check selection of tap, carbide tap may be more suitable then high speed steel taps.