Thread Mills

Thread Mills

Made in USA since 1992

Which thread do you need?

NPS Pipe Threads
NPS Pipe Threads
UN Threads
UN Threads Unified inch threads, coarse and fine 3, 4 and 5 flute options Best for Standard inch threading, blind or through
UN Threads - Single Form
UN Threads - Single Form
UN Threads - Coolant Through
UN Threads - Coolant Through Same UN threads, coolant fed to the cut Clears chips in deep and blind holes Best for Deep holes and lights-out production
NPT Pipe Threads
NPT Pipe Threads Standard tapered pipe thread Sealed with tape or thread compound Best for General pipe and fitting work
NPTF Pipe Threads
NPTF Pipe Threads Dryseal variant of NPT Crests crush to seal metal-to-metal Best for Hydraulic and fuel lines, no sealant
Metric Threads
Metric Threads ISO metric, multiple pitches per diameter 3, 4 and 5 flute options Best for Metric threading from M4 upward

Thread mills cut internal or external threads using a helical milling path rather than a traditional tap, which reduces the risk of tool breakage in blind holes and hardened materials while allowing one tool to cut multiple thread sizes when paired with the right program. We stock thread mills for UN Threads (including coolant-through versions for improved chip evacuation), NPT Pipe Threads, NPTF Pipe Threads, and Metric Threads.

Because thread milling doesn't rely on axial tap pressure to form threads, it's often the preferred method for hardened steels, thin-walled parts, and large-diameter threads where tapping risks breakage. All thread mills are manufactured in the USA.

  • Compare SKU Vendor Cutter Diameter Thread Size (D1) Shank Diameter (D2) Thread Length (L2) Overall Length (L1) Thread Type Number of Flutes Coating In Stock Price Quantity
    A79016 ACT 0.2450 1/16-27 1/4 7/16 2-1/2 NPS Pipe Thread 3 ALTiN 25
    $168.67
  • A78974 ACT 0.0640 2 1/8 5/32 1-1/2 UN Thread 3 Uncoated 36
    $88.39
  • A42772 ACT .115 M4 x 0.70 1/8 .250 2 Metric Thread 3 Uncoated 100
    $142.78
  • A42765 ACT .245 1/16-27 1/4 .437 2-1/2 NPTF Pipe Thread 3 Uncoated 17
    $185.28
  • A42758 ACT .245 1/16-27 1/4 .437 2-1/2 NPT Pipe Thread 3 Uncoated 70
    $185.28
  • A42745 ACT .120 10-32 3/16 .312 2 UN Thread Coolant Through 3 Uncoated 50
    $161.37
  • A42718 ACT .065 2-56 1/8 .125 2 UN Thread 3 Uncoated 52
    $129.26
  • A79017 ACT 0.2400 1/8-27 1/4 0.5700 2-1/2 NPS Pipe Thread 3 ALTiN 100
    $184.67
  • A78975 ACT 0.0720 3 1/8 5/32 1-1/2 UN Thread 3 Uncoated 60
    $88.39
  • A71240 ACT .120 10-32 3/16 .312 2 UN Thread Coolant Through 3 ALTiN 13
    $167.23
  • A72547 ACT .065 2-56 1/8 .125 2 UN Thread 3 ALTiN 25
    $134.45
  • A50088 ACT .115 M4 x 0.70 1/8 .250 2 Metric Thread 3 ALTiN 18
    $147.98
  • A50081 ACT .245 1/16-27 1/4 .437 2-1/2 NPTF Pipe Thread 3 ALTiN 8
    $192.76
  • A50074 ACT .245 1/16-27 1/4 .437 2-1/2 NPT Pipe Thread 3 ALTiN 28
    $192.76
  • A79018 ACT 0.4300 1/4-18 7/16 0.7370 3 NPS Pipe Thread 4 ALTiN 9
    $246.22
  • A78976 ACT 0.0800 4 1/8 1/8 2 UN Thread 3 Uncoated 60
    $92.81
  • A42773 ACT .120 M4.5 x 0.75 1/8 .250 2 Metric Thread 3 Uncoated 79
    $141.87
  • A42766 ACT .310 1/8-27 5/16 .437 2-1/2 NPTF Pipe Thread 4 Uncoated 20
    $183.73
  • A42759 ACT .310 1/8-27 5/16 .437 2-1/2 NPT Pipe Thread 4 Uncoated 100
    $183.73
  • A42746 ACT .180 1/4-20 3/16 .500 2-1/2 UN Thread Coolant Through 3 Uncoated 20
    $171.22
  • A42719 ACT .085 4-40 1/8 .180 2 UN Thread 3 Uncoated 100
    $129.26
  • A79019 ACT 0.4300 3/8-18 7/16 0.7370 3 NPS Pipe Thread 4 ALTiN 22
    $246.22
  • A78977 ACT 0.0800 4 1/8 1/4 2 UN Thread 3 Uncoated 32
    $92.81
  • A71241 ACT .180 1/4-20 3/16 .500 2-1/2 UN Thread Coolant Through 3 ALTiN 14
    $177.45
  • A72548 ACT .085 4-40 1/8 .180 2 UN Thread 3 ALTiN 19
    $134.45
  • A50089 ACT .120 M4.5 x 0.75 1/8 .250 2 Metric Thread 3 ALTiN 15
    $147.07
  • A50082 ACT .310 1/8-27 5/16 .437 2-1/2 NPTF Pipe Thread 4 ALTiN 10
    $193.04
  • A50075 ACT .310 1/8-27 5/16 .437 2-1/2 NPT Pipe Thread 4 ALTiN 66
    $193.04
  • A79020 ACT 0.6200 1/2-14 5/8 1.1500 3-1/2 NPS Pipe Thread 5 ALTiN 18
    $450.80
  • A78978 ACT 0.0980 (2.5 mm) 6 1/8 1/4 2 UN Thread 4 Uncoated 32
    $89.88
  • A42774 ACT .120 M5 x 0.80 3/16 .312 2 Metric Thread 3 Uncoated 22
    $141.87
  • A42767 ACT .370 1/4-18 3/8 .625 3 NPTF Pipe Thread 4 Uncoated 51
    $209.00
  • A42760 ACT .370 1/4-18 3/8 .625 3 NPT Pipe Thread 4 Uncoated 16
    $209.00
  • A42747 ACT .180 1/4-28 3/16 .500 2-1/2 UN Thread Coolant Through 3 Uncoated 16
    $171.22
  • A42720 ACT .100 6-32 1/8 .218 2 UN Thread 3 Uncoated 100
    $138.87
  • A79021 ACT 0.6200 3/4-14 5/8 1.1500 3-1/2 NPS Pipe Thread 5 ALTiN 19
    $450.80
  • A78979 ACT 0.0980 (2.5 mm) 6 1/8 3/8 2 UN Thread 4 Uncoated Available to Order*
    $93.30
  • A71242 ACT .180 1/4-28 3/16 .500 2-1/2 UN Thread Coolant Through 3 ALTiN 10
    $174.56
  • A50090 ACT .120 M5 x 0.80 3/16 .312 2 Metric Thread 3 ALTiN 12
    $147.72
  • A50083 ACT .370 1/4-18 3/8 .625 3 NPTF Pipe Thread 4 ALTiN 15
    $219.54
  • A50076 ACT .370 1/4-18 3/8 .625 3 NPT Pipe Thread 4 ALTiN 16
    $219.54
  • A50049 ACT .100 6-32 1/8 .218 2 UN Thread 3 ALTiN 100
    $144.05
  • A79022 ACT 0.7450 1-11-1/2 3/4 1.3650 4 NPS Pipe Thread 5 ALTiN 23
    $536.11
  • A78980 ACT 0.1200 8 1/8 5/16 2 UN Thread 4 Uncoated 50
    $89.88
  • A42775 ACT .170 M6 x 1.00 3/16 .500 2-1/2 Metric Thread 3 Uncoated 100
    $155.81
  • A42768 ACT .370 3/8-18 3/8 .625 3 NPTF Pipe Thread 4 Uncoated 20
    $209.00
  • A42761 ACT .370 3/8-18 3/8 .625 3 NPT Pipe Thread 4 Uncoated 100
    $209.00
  • A42748 ACT .240 5/16-18 1/4 .625 2-1/2 UN Thread Coolant Through 3 Uncoated 4
    $211.10
  • A42721 ACT .115 8-32 1/8 .250 2 UN Thread 3 Uncoated 100
    $138.87
  • A78981 ACT 0.1200 8 1/8 1/2 2 UN Thread 4 Uncoated 22
    $93.30
  • A71243 ACT .240 5/16-18 1/4 .625 2-1/2 UN Thread Coolant Through 3 ALTiN 12
    $218.56
  • A50091 ACT .170 M6 x 1.00 3/16 .500 2-1/2 Metric Thread 3 ALTiN 37
    $162.03
  • A50084 ACT .370 3/8-18 3/8 .625 3 NPTF Pipe Thread 4 ALTiN 11
    $219.54
  • A50077 ACT .370 3/8-18 3/8 .625 3 NPT Pipe Thread 4 ALTiN 24
    $219.54
  • A50050 ACT .115 8-32 1/8 .250 2 UN Thread 3 ALTiN 16
    $144.05
  • A78982 ACT 0.1380 (3.5 mm) 10 3/16 3/8 2 UN Thread 4 Uncoated 32
    $86.50
  • A42776 ACT .235 M8 x 0.75 1/4 .625 2-1/2 Metric Thread 3 Uncoated 26
    $185.28
  • A42769 ACT .495 1/2-14 1/2 .875 3-1/2 NPTF Pipe Thread 4 Uncoated 100
    $339.07
  • A42762 ACT .495 1/2-14 1/2 .875 3-1/2 NPT Pipe Thread 4 Uncoated 100
    $339.07
  • A42749 ACT .240 5/16-24 1/4 .625 2-1/2 UN Thread Coolant Through 3 Uncoated 85
    $212.17
  • A42722 ACT .115 8-36 1/8 .250 2 UN Thread 3 Uncoated 42
    $138.87
  • A78983 ACT 0.1380 (3.5 mm) 10 3/16 5/8 2 UN Thread 4 Uncoated Available to Order*
    $90.63
  • A71244 ACT .240 5/16-24 1/4 .625 2-1/2 UN Thread Coolant Through 3 ALTiN 25
    $219.64
  • A50092 ACT .235 M8 x 0.75 1/4 .625 2-1/2 Metric Thread 3 ALTiN 10
    $192.76
  • A50085 ACT .495 1/2-14 1/2 .875 3-1/2 NPTF Pipe Thread 4 ALTiN 15
    $356.48
  • A50078 ACT .495 1/2-14 1/2 .875 3-1/2 NPT Pipe Thread 4 ALTiN 54
    $357.76
  • A50051 ACT .115 8-36 1/8 .250 2 UN Thread 3 ALTiN 29
    $144.05
  • A78984 ACT 0.1600 12 3/16 5/8 2 UN Thread 4 Uncoated 50
    $90.63
  • A42777 ACT .235 M8 x 1.00 1/4 .625 2-1/2 Metric Thread 3 Uncoated 38
    $185.28
  • A42770 ACT .495 3/4-14 1/2 .875 3-1/2 NPTF Pipe Thread 4 Uncoated 41
    $339.07
  • A42763 ACT .495 3/4-14 1/2 .875 3-1/2 NPT Pipe Thread 4 Uncoated 35
    $339.07
  • A42750 ACT .290 3/8-16 5/16 .750 3 UN Thread Coolant Through 4 Uncoated 21
    $263.13
  • A42723 ACT .120 10-24 3/16 .312 2 UN Thread 3 Uncoated 100
    $138.28
  • A78985 ACT 0.1800 1/4 3/16 1/2 2 UN Thread 4 Uncoated 19
    $94.26
  • A71245 ACT .290 3/8-16 5/16 .750 3 UN Thread Coolant Through 4 ALTiN 14
    $272.08
  • A50093 ACT .235 M8 x 1.00 1/4 .625 2-1/2 Metric Thread 3 ALTiN 9
    $192.76
  • A50086 ACT .495 3/4-14 1/2 .875 3-1/2 NPTF Pipe Thread 4 ALTiN 4
    $357.76
  • A50079 ACT .495 3/4-14 1/2 .875 3-1/2 NPT Pipe Thread 4 ALTiN 31
    $357.76
  • A50052 ACT .120 10-24 3/16 .312 2 UN Thread 3 ALTiN 100
    $144.15
  • A78986 ACT 0.1800 1/4 3/16 3/4 2 UN Thread 4 Uncoated Available to Order*
    $96.11
  • A42778 ACT .235 M8 x 1.25 1/4 .625 2-1/2 Metric Thread 3 Uncoated 100
    $185.28
  • A42771 ACT .620 1-11-1/2 3/4 1.125 4 NPTF Pipe Thread 5 Uncoated 71
    $451.59
  • A42764 ACT .620 1-11-1/2 3/4 1.125 4 NPT Pipe Thread 5 Uncoated 67
    $451.59
  • A42751 ACT .290 3/8-24 5/16 .750 3 UN Thread Coolant Through 4 Uncoated 16
    $263.13
  • A42724 ACT .120 10-32 3/16 .312 2 UN Thread 3 Uncoated 100
    $138.28
  • A78987 ACT 0.2400 5/16 1/4 1/2 2-1/2 UN Thread 4 Uncoated 49
    $110.75
  • A71246 ACT .290 3/8-24 5/16 .750 3 UN Thread Coolant Through 4 ALTiN 3
    $272.08
  • A50094 ACT .235 M8 x 1.25 1/4 .625 2-1/2 Metric Thread 3 ALTiN 23
    $192.76
  • A50087 ACT .620 1-11-1/2 3/4 1.125 4 NPTF Pipe Thread 5 ALTiN 11
    $479.09
  • A50080 ACT .620 1-11-1/2 3/4 1.125 4 NPT Pipe Thread 5 ALTiN 20
    $479.09
  • A50053 ACT .120 10-32 3/16 .312 2 UN Thread 3 ALTiN 16
    $144.15
  • A78988 ACT 0.2400 5/16 1/4 3/4 2-1/2 UN Thread 4 Uncoated 21
    $115.94
  • A42779 ACT .300 M10 x 1.25 5/16 .750 3 Metric Thread 4 Uncoated 27
    $219.72
  • A42752 ACT .340 7/16-14 3/8 .875 3 UN Thread Coolant Through 4 Uncoated 15
    $304.57
  • A42725 ACT .180 1/4-20 3/16 .500 2-1/2 UN Thread 3 Uncoated 100
    $156.83
  • A78989 ACT 0.3000 3/8 3/8 3/4 2-1/2 UN Thread 4 Uncoated 33
    $137.46
  • A71247 ACT .340 7/16-14 3/8 .875 3 UN Thread Coolant Through 4 ALTiN 7
    $228.99
  • A50095 ACT .300 M10 x 1.25 5/16 .750 3 Metric Thread 4 ALTiN 7
    $228.63
  • A50054 ACT .180 1/4-20 3/16 .500 2-1/2 UN Thread 3 ALTiN 100
    $163.02
  • A78990 ACT 0.3000 3/8 3/8 1 2-1/2 UN Thread 4 Uncoated 24
    $144.19

* Lead times can vary from 1–10 business days. Call (908) 98-ATLAS or email sales@atlascuttingtools.com for details.

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