® Thread Turning Technical Section Anvil Change Recommendation As can be seen from the chart, some Pitch to Diameter combinations require an anvil change. If change is required, use AE anvils for EX-RH and IN-LH toolholders and AI anvils for IN-RH and EX-LH toolholders. ACME STUB ACME TRAPEZ (DIN 103) ROUND (DIN 405) As can be seen from the chart, most applications do not require an anvil change. If change is required, use AE anvils for EX-RH and IN-LH toolholders and AI anvils for IN-RH and EX-LH toolholders. PARTIAL PROFILE 60° PARTIAL PROFILE 55° ISO UN WHIT. NPT BSPT As can be seen from the chart, most applications require an anvil change. In most cases a negative anvil is required. Use AE anvils for EX-RH and IN-LH toolholders and AI anvils for IN-RH and EX-LH toolholders. AMERICAN BUTTRESS SAGENGEWINDE (DIN 513) Wrong Correct A04-7