Find tap drill sizes for common SAE and metric threads. Use the quick lookup and browse the charts; printable shop references are coming soon.
Start by checking the fastener diameter and thread pitch. Choose UNC, UNF, or the correct metric pitch, then verify the result against your tap and the material being threaded. Reverse Lookup is helpful when you already have a drill size.
Close: smaller pass-through clearance, requiring more careful alignment and control. Normal: a general assembly fit. Loose: more installation room where allowed.
Inch: ASME B18.2.8 hole-size classes, displayed as published minimum diameters. Metric: ISO 273 fine, medium and coarse clearance series. Clearance selection is based on fastener diameter, not thread pitch.
A nominal drill marking does not guarantee the produced hole dimension. Use the engineering drawing or manufacturer specification when available, especially for location-critical joints.
Technical references: ASME B18.2.8 · Inch fastener table · Metric clearance sizes.
47 SAE entries cross-checked (23 UNC, 24 UNF). Select any thread to load its tap drill into the Finder. Values are common cutting-tap reference sizes, not mandatory hole diameters or certified thread-class specifications.
| THREAD SIZE | TAP DRILL | DRILL Ø (IN) | DRILL Ø (MM) |
|---|---|---|---|
| #53 | 0.0595″ | 1.511 mm | |
| #50 | 0.0700″ | 1.778 mm | |
| #47 | 0.0785″ | 1.994 mm | |
| #43 | 0.0890″ | 2.261 mm | |
| #38 | 0.1015″ | 2.578 mm | |
| #36 | 0.1065″ | 2.705 mm | |
| #29 | 0.1360″ | 3.454 mm | |
| #25 | 0.1495″ | 3.797 mm | |
| #16 | 0.1770″ | 4.496 mm | |
| #7 | 0.2010″ | 5.105 mm | |
| F | 0.2570″ | 6.528 mm | |
| 5/16″ | 0.3125″ | 7.938 mm | |
| U | 0.3680″ | 9.347 mm | |
| 27/64″ | 0.4219″ | 10.716 mm | |
| 31/64″ | 0.4844″ | 12.303 mm | |
| 17/32″ | 0.5313″ | 13.494 mm | |
| 21/32″ | 0.6563″ | 16.669 mm | |
| 49/64″ | 0.7656″ | 19.447 mm | |
| 7/8″ | 0.8750″ | 22.225 mm | |
| 63/64″ | 0.9844″ | 25.003 mm | |
| 1-7/64″ | 1.1094″ | 28.178 mm | |
| 1-7/32″ | 1.2188″ | 30.956 mm | |
| 1-11/32″ | 1.3438″ | 34.131 mm |
Select a thread size to load the Tap & Drill Finder. Listed diameters describe the drill, not the finished thread or a metric-thread equivalent. These are general cutting-tap references; verify material, tolerance and tool-specific recommendations.
| THREAD SIZE | TAP DRILL | DRILL Ø (IN) | DRILL Ø (MM) |
|---|---|---|---|
| 3/64″ | 0.0469″ | 1.191 mm | |
| #53 | 0.0595″ | 1.511 mm | |
| #50 | 0.0700″ | 1.778 mm | |
| #45 | 0.0820″ | 2.083 mm | |
| #42 | 0.0935″ | 2.375 mm | |
| #37 | 0.1040″ | 2.642 mm | |
| #33 | 0.1130″ | 2.870 mm | |
| #29 | 0.1360″ | 3.454 mm | |
| #21 | 0.1590″ | 4.039 mm | |
| #14 | 0.1820″ | 4.623 mm | |
| #3 | 0.2130″ | 5.410 mm | |
| I | 0.2720″ | 6.909 mm | |
| Q | 0.3320″ | 8.433 mm | |
| 25/64″ | 0.3906″ | 9.922 mm | |
| 29/64″ | 0.4531″ | 11.509 mm | |
| 33/64″ | 0.5156″ | 13.097 mm | |
| 37/64″ | 0.5781″ | 14.684 mm | |
| 11/16″ | 0.6875″ | 17.463 mm | |
| 13/16″ | 0.8125″ | 20.638 mm | |
| 59/64″ | 0.9219″ | 23.416 mm | |
| 1-3/64″ | 1.0469″ | 26.591 mm | |
| 1-11/64″ | 1.1719″ | 29.766 mm | |
| 1-19/64″ | 1.2969″ | 32.941 mm | |
| 1-27/64″ | 1.4219″ | 36.116 mm |
Select a thread size to load the Tap & Drill Finder. Listed diameters describe the drill, not the finished thread or a metric-thread equivalent. These are general cutting-tap references; verify material, tolerance and tool-specific recommendations.
Tap-drill sizes are general cutting-tap starting recommendations, not hole diameters mandated by ASME B1.1. The exact hole depends on the thread tolerance, material, intended engagement, and specific tool. In particular, TapBase uses #45 for #3-56 UNF and #14 for #12-28 UNF as common general-reference defaults; TEKTON's hand-tap chart instead lists smaller #46 and #15. Other reference variations include #2-56 (#50 or #51), #12-24 (#16 or #17), and 7/16-20 (25/64″ or W). The Finder identifies alternate recommendations when recorded.
Accuracy convention: TapBase stores the exact nominal number, letter, or fractional drill diameter, converts from that unrounded value using 1 in = 25.4 mm exactly, and displays inches to four decimals and millimeters to three, with round-half-up formatting. A displayed decimal is an approximation when the original drill is fractional. Published recommendations vary in actual thread engagement—do not assume every row equals exactly 75%.
Thread-series distinction: 1-12 UNF is the standard fine-series entry here. A 1-14 thread is not included in this UNF series chart; check the actual specified thread series before substituting a tap. The 1-3/8-inch and larger tap drills are industrial reference values, and the actual tap or thread specification must be confirmed.
Sources reviewed: TEKTON tap-and-die reference chart, Engineering ToolBox UNC/UNF thread-series tables, Speed & Feed Calc tap-drill chart, and expanded UNC/UNF tap-drill comparison.
50 reviewed metric cutting-tap references: 27 coarse and 23 fine-pitch combinations. Values describe common drill starting diameters, not universal hole or thread-tolerance specifications. Select a thread to load it into the Finder.
| THREAD SIZE | THREAD PITCH | TAP DRILL Ø (MM) | DRILL Ø (IN) |
|---|---|---|---|
| 0.35 mm | 1.25 mm | 0.0492″ | |
| 0.35 mm | 1.45 mm | 0.0571″ | |
| 0.4 mm | 1.6 mm | 0.0630″ | |
| 0.45 mm | 1.75 mm | 0.0689″ | |
| 0.45 mm | 2.05 mm | 0.0807″ | |
| 0.5 mm | 2.5 mm | 0.0984″ | |
| 0.6 mm | 2.9 mm | 0.1142″ | |
| 0.7 mm | 3.3 mm | 0.1299″ | |
| 0.75 mm | 3.7 mm | 0.1457″ | |
| 0.8 mm | 4.2 mm | 0.1654″ | |
| 1.0 mm | 5.0 mm | 0.1969″ | |
| 1.0 mm | 6.0 mm | 0.2362″ | |
| 1.25 mm | 6.8 mm | 0.2677″ | |
| 1.25 mm | 7.8 mm | 0.3071″ | |
| 1.5 mm | 8.5 mm | 0.3346″ | |
| 1.5 mm | 9.5 mm | 0.3740″ | |
| 1.75 mm | 10.2 mm | 0.4016″ | |
| 2.0 mm | 12.0 mm | 0.4724″ | |
| 2.0 mm | 14.0 mm | 0.5512″ | |
| 2.5 mm | 15.5 mm | 0.6102″ | |
| 2.5 mm | 17.5 mm | 0.6890″ | |
| 2.5 mm | 19.5 mm | 0.7677″ | |
| 3.0 mm | 21.0 mm | 0.8268″ | |
| 3.0 mm | 24.0 mm | 0.9449″ | |
| 3.5 mm | 26.5 mm | 1.0433″ | |
| 3.5 mm | 29.5 mm | 1.1614″ | |
| 4.0 mm | 32.0 mm | 1.2598″ |
Select a thread to load it into the Finder. Dimensions describe the tap drill, not the finished thread. Values are common cutting-tap starting sizes; verify tap manufacturer, material and hole-tolerance requirements.
| THREAD SIZE | THREAD PITCH | TAP DRILL Ø (MM) | DRILL Ø (IN) |
|---|---|---|---|
| 0.35 mm | 2.65 mm | 0.1043″ | |
| 0.5 mm | 3.5 mm | 0.1378″ | |
| 0.5 mm | 4.5 mm | 0.1772″ | |
| 0.75 mm | 5.2 mm | 0.2047″ | |
| 1.0 mm | 7.0 mm | 0.2756″ | |
| 1.0 mm | 9.0 mm | 0.3543″ | |
| 1.25 mm | 8.8 mm | 0.3465″ | |
| 1.25 mm | 10.8 mm | 0.4252″ | |
| 1.5 mm | 10.5 mm | 0.4134″ | |
| 1.5 mm | 12.5 mm | 0.4921″ | |
| 1.5 mm | 14.5 mm | 0.5709″ | |
| 1.5 mm | 16.5 mm | 0.6496″ | |
| 2.0 mm | 16.0 mm | 0.6299″ | |
| 1.5 mm | 18.5 mm | 0.7283″ | |
| 2.0 mm | 18.0 mm | 0.7087″ | |
| 1.5 mm | 20.5 mm | 0.8071″ | |
| 2.0 mm | 20.0 mm | 0.7874″ | |
| 2.0 mm | 22.0 mm | 0.8661″ | |
| 2.0 mm | 25.0 mm | 0.9843″ | |
| 2.0 mm | 28.0 mm | 1.1024″ | |
| 2.0 mm | 31.0 mm | 1.2205″ | |
| 3.0 mm | 33.0 mm | 1.2992″ | |
| 3.0 mm | 36.0 mm | 1.4173″ |
Select a thread to load it into the Finder. Dimensions describe the tap drill, not the finished thread. Values are common cutting-tap starting sizes; verify tap manufacturer, material and hole-tolerance requirements.
What is being listed? These are common starting drills for cutting taps. ISO metric nominal diameter and pitch do not by themselves prescribe a single drill for all materials, percentage thread engagements, tolerances, or tap geometry. The practical D − P calculation is an approximation; real drill-series availability can change the chosen size.
Published variations: M4.5 × 0.75 uses 3.7 mm (Haas tool recommendation, versus theoretical 3.75 mm). M6 × 0.75 commonly uses 5.2 mm, while 5.25 mm also appears; M10 × 1.25 often specifies 8.8 mm instead of theoretical 8.75 mm; M12 × 1.25 often specifies 10.8 mm instead of 10.75 mm. These are alternatives for different tooling and engagement needs, not interchangeable assurances.
Scope: 27 metric coarse sizes, M1.6 through M36, including less-common M4.5, M9 and M11; 23 fine-pitch combinations, M3 × 0.35 through M39 × 3. Multiple fine pitches for one nominal diameter are separately labeled and are not interchangeable.
Sources compared: Fractory metric chart, MachinistCharts tap-drill references, TR Fastenings coarse pitches, CustomPartNet drill chart, MLC metric pitch reference and Haas M4.5 cutting-tap recommendation.
Validation boundary: Diameters/conversions and public source comparison are checked for these rows; this is not a certified ISO 261/724/965 conformance review or a manufacturer approval for your specific material or machine. Consult toolmaker recommendations for forming taps and special applications.
Full #1–#80 and A–Z nominal drill series, fractional sizes in 1/64″ increments through 1½″, and a practical selection of metric diameters through 36 mm. Values are nominal drill diameters, not measured holes or universal tap-drill recommendations.
| DRILL SIZE | TYPE | DECIMAL INCHES | METRIC EQUIVALENT |
|---|---|---|---|
| #80 | Number | 0.0135″ | 0.343 mm |
| #79 | Number | 0.0145″ | 0.368 mm |
| 1/64″ | Fractional | 0.0156″ | 0.397 mm |
| #78 | Number | 0.0160″ | 0.406 mm |
| #77 | Number | 0.0180″ | 0.457 mm |
| 0.5 mm | Metric | 0.0197″ | 0.500 mm |
| #76 | Number | 0.0200″ | 0.508 mm |
| #75 | Number | 0.0210″ | 0.533 mm |
| #74 | Number | 0.0225″ | 0.572 mm |
| 0.6 mm | Metric | 0.0236″ | 0.600 mm |
| #73 | Number | 0.0240″ | 0.610 mm |
| #72 | Number | 0.0250″ | 0.635 mm |
| #71 | Number | 0.0260″ | 0.660 mm |
| 0.7 mm | Metric | 0.0276″ | 0.700 mm |
| #70 | Number | 0.0280″ | 0.711 mm |
| #69 | Number | 0.0292″ | 0.742 mm |
| #68 | Number | 0.0310″ | 0.787 mm |
| 1/32″ | Fractional | 0.0313″ | 0.794 mm |
| 0.8 mm | Metric | 0.0315″ | 0.800 mm |
| #67 | Number | 0.0320″ | 0.813 mm |
| #66 | Number | 0.0330″ | 0.838 mm |
| #65 | Number | 0.0350″ | 0.889 mm |
| 0.9 mm | Metric | 0.0354″ | 0.900 mm |
| #64 | Number | 0.0360″ | 0.914 mm |
| #63 | Number | 0.0370″ | 0.940 mm |
| #62 | Number | 0.0380″ | 0.965 mm |
| #61 | Number | 0.0390″ | 0.991 mm |
| 1.0 mm | Metric | 0.0394″ | 1.000 mm |
| #60 | Number | 0.0400″ | 1.016 mm |
| #59 | Number | 0.0410″ | 1.041 mm |
| #58 | Number | 0.0420″ | 1.067 mm |
| #57 | Number | 0.0430″ | 1.092 mm |
| 1.1 mm | Metric | 0.0433″ | 1.100 mm |
| #56 | Number | 0.0465″ | 1.181 mm |
| 3/64″ | Fractional | 0.0469″ | 1.191 mm |
| 1.2 mm | Metric | 0.0472″ | 1.200 mm |
| 1.25 mm | Metric | 0.0492″ | 1.250 mm |
| 1.3 mm | Metric | 0.0512″ | 1.300 mm |
| #55 | Number | 0.0520″ | 1.321 mm |
| #54 | Number | 0.0550″ | 1.397 mm |
| 1.4 mm | Metric | 0.0551″ | 1.400 mm |
| 1.45 mm | Metric | 0.0571″ | 1.450 mm |
| 1.5 mm | Metric | 0.0591″ | 1.500 mm |
| #53 | Number | 0.0595″ | 1.511 mm |
| 1/16″ | Fractional | 0.0625″ | 1.588 mm |
| 1.6 mm | Metric | 0.0630″ | 1.600 mm |
| #52 | Number | 0.0635″ | 1.613 mm |
| 1.7 mm | Metric | 0.0669″ | 1.700 mm |
| #51 | Number | 0.0670″ | 1.702 mm |
| 1.75 mm | Metric | 0.0689″ | 1.750 mm |
| #50 | Number | 0.0700″ | 1.778 mm |
| 1.8 mm | Metric | 0.0709″ | 1.800 mm |
| #49 | Number | 0.0730″ | 1.854 mm |
| 1.9 mm | Metric | 0.0748″ | 1.900 mm |
| #48 | Number | 0.0760″ | 1.930 mm |
| 5/64″ | Fractional | 0.0781″ | 1.984 mm |
| #47 | Number | 0.0785″ | 1.994 mm |
| 2.0 mm | Metric | 0.0787″ | 2.000 mm |
| 2.05 mm | Metric | 0.0807″ | 2.050 mm |
| #46 | Number | 0.0810″ | 2.057 mm |
| #45 | Number | 0.0820″ | 2.083 mm |
| 2.1 mm | Metric | 0.0827″ | 2.100 mm |
| #44 | Number | 0.0860″ | 2.184 mm |
| 2.2 mm | Metric | 0.0866″ | 2.200 mm |
| #43 | Number | 0.0890″ | 2.261 mm |
| 2.3 mm | Metric | 0.0906″ | 2.300 mm |
| #42 | Number | 0.0935″ | 2.375 mm |
| 3/32″ | Fractional | 0.0938″ | 2.381 mm |
| 2.4 mm | Metric | 0.0945″ | 2.400 mm |
| #41 | Number | 0.0960″ | 2.438 mm |
| #40 | Number | 0.0980″ | 2.489 mm |
| 2.5 mm | Metric | 0.0984″ | 2.500 mm |
| #39 | Number | 0.0995″ | 2.527 mm |
| #38 | Number | 0.1015″ | 2.578 mm |
| 2.6 mm | Metric | 0.1024″ | 2.600 mm |
| #37 | Number | 0.1040″ | 2.642 mm |
| 2.65 mm | Metric | 0.1043″ | 2.650 mm |
| 2.7 mm | Metric | 0.1063″ | 2.700 mm |
| #36 | Number | 0.1065″ | 2.705 mm |
| 7/64″ | Fractional | 0.1094″ | 2.778 mm |
| #35 | Number | 0.1100″ | 2.794 mm |
| 2.8 mm | Metric | 0.1102″ | 2.800 mm |
| #34 | Number | 0.1110″ | 2.819 mm |
| #33 | Number | 0.1130″ | 2.870 mm |
| 2.9 mm | Metric | 0.1142″ | 2.900 mm |
| #32 | Number | 0.1160″ | 2.946 mm |
| 3.0 mm | Metric | 0.1181″ | 3.000 mm |
| #31 | Number | 0.1200″ | 3.048 mm |
| 3.1 mm | Metric | 0.1220″ | 3.100 mm |
| 1/8″ | Fractional | 0.1250″ | 3.175 mm |
| 3.2 mm | Metric | 0.1260″ | 3.200 mm |
| #30 | Number | 0.1285″ | 3.264 mm |
| 3.3 mm | Metric | 0.1299″ | 3.300 mm |
| 3.4 mm | Metric | 0.1339″ | 3.400 mm |
| #29 | Number | 0.1360″ | 3.454 mm |
| 3.5 mm | Metric | 0.1378″ | 3.500 mm |
| #28 | Number | 0.1405″ | 3.569 mm |
| 9/64″ | Fractional | 0.1406″ | 3.572 mm |
| 3.6 mm | Metric | 0.1417″ | 3.600 mm |
| #27 | Number | 0.1440″ | 3.658 mm |
| 3.7 mm | Metric | 0.1457″ | 3.700 mm |
| #26 | Number | 0.1470″ | 3.734 mm |
| 3.75 mm | Metric | 0.1476″ | 3.750 mm |
| #25 | Number | 0.1495″ | 3.797 mm |
| 3.8 mm | Metric | 0.1496″ | 3.800 mm |
| #24 | Number | 0.1520″ | 3.861 mm |
| 3.9 mm | Metric | 0.1535″ | 3.900 mm |
| #23 | Number | 0.1540″ | 3.912 mm |
| 5/32″ | Fractional | 0.1563″ | 3.969 mm |
| #22 | Number | 0.1570″ | 3.988 mm |
| 4.0 mm | Metric | 0.1575″ | 4.000 mm |
| #21 | Number | 0.1590″ | 4.039 mm |
| #20 | Number | 0.1610″ | 4.089 mm |
| 4.1 mm | Metric | 0.1614″ | 4.100 mm |
| 4.2 mm | Metric | 0.1654″ | 4.200 mm |
| #19 | Number | 0.1660″ | 4.216 mm |
| 4.3 mm | Metric | 0.1693″ | 4.300 mm |
| #18 | Number | 0.1695″ | 4.305 mm |
| 11/64″ | Fractional | 0.1719″ | 4.366 mm |
| #17 | Number | 0.1730″ | 4.394 mm |
| 4.4 mm | Metric | 0.1732″ | 4.400 mm |
| #16 | Number | 0.1770″ | 4.496 mm |
| 4.5 mm | Metric | 0.1772″ | 4.500 mm |
| #15 | Number | 0.1800″ | 4.572 mm |
| 4.6 mm | Metric | 0.1811″ | 4.600 mm |
| #14 | Number | 0.1820″ | 4.623 mm |
| #13 | Number | 0.1850″ | 4.699 mm |
| 4.7 mm | Metric | 0.1850″ | 4.700 mm |
| 3/16″ | Fractional | 0.1875″ | 4.763 mm |
| 4.8 mm | Metric | 0.1890″ | 4.800 mm |
| #12 | Number | 0.1890″ | 4.801 mm |
| #11 | Number | 0.1910″ | 4.851 mm |
| 4.9 mm | Metric | 0.1929″ | 4.900 mm |
| #10 | Number | 0.1935″ | 4.915 mm |
| #9 | Number | 0.1960″ | 4.978 mm |
| 5.0 mm | Metric | 0.1969″ | 5.000 mm |
| #8 | Number | 0.1990″ | 5.055 mm |
| 5.1 mm | Metric | 0.2008″ | 5.100 mm |
| #7 | Number | 0.2010″ | 5.105 mm |
| 13/64″ | Fractional | 0.2031″ | 5.159 mm |
| #6 | Number | 0.2040″ | 5.182 mm |
| 5.2 mm | Metric | 0.2047″ | 5.200 mm |
| #5 | Number | 0.2055″ | 5.220 mm |
| 5.25 mm | Metric | 0.2067″ | 5.250 mm |
| 5.3 mm | Metric | 0.2087″ | 5.300 mm |
| #4 | Number | 0.2090″ | 5.309 mm |
| 5.4 mm | Metric | 0.2126″ | 5.400 mm |
| #3 | Number | 0.2130″ | 5.410 mm |
| 5.5 mm | Metric | 0.2165″ | 5.500 mm |
| 7/32″ | Fractional | 0.2188″ | 5.556 mm |
| 5.6 mm | Metric | 0.2205″ | 5.600 mm |
| #2 | Number | 0.2210″ | 5.613 mm |
| 5.7 mm | Metric | 0.2244″ | 5.700 mm |
| #1 | Number | 0.2280″ | 5.791 mm |
| 5.8 mm | Metric | 0.2283″ | 5.800 mm |
| 5.9 mm | Metric | 0.2323″ | 5.900 mm |
| A | Letter | 0.2340″ | 5.944 mm |
| 15/64″ | Fractional | 0.2344″ | 5.953 mm |
| 6.0 mm | Metric | 0.2362″ | 6.000 mm |
| B | Letter | 0.2380″ | 6.045 mm |
| 6.1 mm | Metric | 0.2402″ | 6.100 mm |
| C | Letter | 0.2420″ | 6.147 mm |
| 6.2 mm | Metric | 0.2441″ | 6.200 mm |
| D | Letter | 0.2460″ | 6.248 mm |
| 6.3 mm | Metric | 0.2480″ | 6.300 mm |
| E | Letter | 0.2500″ | 6.350 mm |
| 1/4″ | Fractional | 0.2500″ | 6.350 mm |
| 6.4 mm | Metric | 0.2520″ | 6.400 mm |
| 6.5 mm | Metric | 0.2559″ | 6.500 mm |
| F | Letter | 0.2570″ | 6.528 mm |
| 6.6 mm | Metric | 0.2598″ | 6.600 mm |
| G | Letter | 0.2610″ | 6.629 mm |
| 6.7 mm | Metric | 0.2638″ | 6.700 mm |
| 17/64″ | Fractional | 0.2656″ | 6.747 mm |
| H | Letter | 0.2660″ | 6.756 mm |
| 6.8 mm | Metric | 0.2677″ | 6.800 mm |
| 6.9 mm | Metric | 0.2717″ | 6.900 mm |
| I | Letter | 0.2720″ | 6.909 mm |
| 7.0 mm | Metric | 0.2756″ | 7.000 mm |
| J | Letter | 0.2770″ | 7.036 mm |
| 7.1 mm | Metric | 0.2795″ | 7.100 mm |
| K | Letter | 0.2810″ | 7.137 mm |
| 9/32″ | Fractional | 0.2813″ | 7.144 mm |
| 7.2 mm | Metric | 0.2835″ | 7.200 mm |
| 7.3 mm | Metric | 0.2874″ | 7.300 mm |
| L | Letter | 0.2900″ | 7.366 mm |
| 7.4 mm | Metric | 0.2913″ | 7.400 mm |
| M | Letter | 0.2950″ | 7.493 mm |
| 7.5 mm | Metric | 0.2953″ | 7.500 mm |
| 19/64″ | Fractional | 0.2969″ | 7.541 mm |
| 7.6 mm | Metric | 0.2992″ | 7.600 mm |
| N | Letter | 0.3020″ | 7.671 mm |
| 7.7 mm | Metric | 0.3031″ | 7.700 mm |
| 7.8 mm | Metric | 0.3071″ | 7.800 mm |
| 7.9 mm | Metric | 0.3110″ | 7.900 mm |
| 5/16″ | Fractional | 0.3125″ | 7.938 mm |
| 8.0 mm | Metric | 0.3150″ | 8.000 mm |
| O | Letter | 0.3160″ | 8.026 mm |
| 8.1 mm | Metric | 0.3189″ | 8.100 mm |
| 8.2 mm | Metric | 0.3228″ | 8.200 mm |
| P | Letter | 0.3230″ | 8.204 mm |
| 8.3 mm | Metric | 0.3268″ | 8.300 mm |
| 21/64″ | Fractional | 0.3281″ | 8.334 mm |
| 8.4 mm | Metric | 0.3307″ | 8.400 mm |
| Q | Letter | 0.3320″ | 8.433 mm |
| 8.5 mm | Metric | 0.3346″ | 8.500 mm |
| 8.6 mm | Metric | 0.3386″ | 8.600 mm |
| R | Letter | 0.3390″ | 8.611 mm |
| 8.7 mm | Metric | 0.3425″ | 8.700 mm |
| 11/32″ | Fractional | 0.3438″ | 8.731 mm |
| 8.75 mm | Metric | 0.3445″ | 8.750 mm |
| 8.8 mm | Metric | 0.3465″ | 8.800 mm |
| S | Letter | 0.3480″ | 8.839 mm |
| 8.9 mm | Metric | 0.3504″ | 8.900 mm |
| 9.0 mm | Metric | 0.3543″ | 9.000 mm |
| T | Letter | 0.3580″ | 9.093 mm |
| 9.1 mm | Metric | 0.3583″ | 9.100 mm |
| 23/64″ | Fractional | 0.3594″ | 9.128 mm |
| 9.2 mm | Metric | 0.3622″ | 9.200 mm |
| 9.3 mm | Metric | 0.3661″ | 9.300 mm |
| U | Letter | 0.3680″ | 9.347 mm |
| 9.4 mm | Metric | 0.3701″ | 9.400 mm |
| 9.5 mm | Metric | 0.3740″ | 9.500 mm |
| 3/8″ | Fractional | 0.3750″ | 9.525 mm |
| V | Letter | 0.3770″ | 9.576 mm |
| 9.6 mm | Metric | 0.3780″ | 9.600 mm |
| 9.7 mm | Metric | 0.3819″ | 9.700 mm |
| 9.8 mm | Metric | 0.3858″ | 9.800 mm |
| W | Letter | 0.3860″ | 9.804 mm |
| 9.9 mm | Metric | 0.3898″ | 9.900 mm |
| 25/64″ | Fractional | 0.3906″ | 9.922 mm |
| 10.0 mm | Metric | 0.3937″ | 10.000 mm |
| X | Letter | 0.3970″ | 10.084 mm |
| 10.1 mm | Metric | 0.3976″ | 10.100 mm |
| 10.2 mm | Metric | 0.4016″ | 10.200 mm |
| Y | Letter | 0.4040″ | 10.262 mm |
| 10.3 mm | Metric | 0.4055″ | 10.300 mm |
| 13/32″ | Fractional | 0.4063″ | 10.319 mm |
| 10.4 mm | Metric | 0.4094″ | 10.400 mm |
| Z | Letter | 0.4130″ | 10.490 mm |
| 10.5 mm | Metric | 0.4134″ | 10.500 mm |
| 10.6 mm | Metric | 0.4173″ | 10.600 mm |
| 10.7 mm | Metric | 0.4213″ | 10.700 mm |
| 27/64″ | Fractional | 0.4219″ | 10.716 mm |
| 10.75 mm | Metric | 0.4232″ | 10.750 mm |
| 10.8 mm | Metric | 0.4252″ | 10.800 mm |
| 10.9 mm | Metric | 0.4291″ | 10.900 mm |
| 11.0 mm | Metric | 0.4331″ | 11.000 mm |
| 11.1 mm | Metric | 0.4370″ | 11.100 mm |
| 7/16″ | Fractional | 0.4375″ | 11.113 mm |
| 11.2 mm | Metric | 0.4409″ | 11.200 mm |
| 11.3 mm | Metric | 0.4449″ | 11.300 mm |
| 11.4 mm | Metric | 0.4488″ | 11.400 mm |
| 11.5 mm | Metric | 0.4528″ | 11.500 mm |
| 29/64″ | Fractional | 0.4531″ | 11.509 mm |
| 11.6 mm | Metric | 0.4567″ | 11.600 mm |
| 11.7 mm | Metric | 0.4606″ | 11.700 mm |
| 11.8 mm | Metric | 0.4646″ | 11.800 mm |
| 11.9 mm | Metric | 0.4685″ | 11.900 mm |
| 15/32″ | Fractional | 0.4688″ | 11.906 mm |
| 12.0 mm | Metric | 0.4724″ | 12.000 mm |
| 12.1 mm | Metric | 0.4764″ | 12.100 mm |
| 12.2 mm | Metric | 0.4803″ | 12.200 mm |
| 12.3 mm | Metric | 0.4843″ | 12.300 mm |
| 31/64″ | Fractional | 0.4844″ | 12.303 mm |
| 12.4 mm | Metric | 0.4882″ | 12.400 mm |
| 12.5 mm | Metric | 0.4921″ | 12.500 mm |
| 12.6 mm | Metric | 0.4961″ | 12.600 mm |
| 1/2″ | Fractional | 0.5000″ | 12.700 mm |
| 12.7 mm | Metric | 0.5000″ | 12.700 mm |
| 12.8 mm | Metric | 0.5039″ | 12.800 mm |
| 12.9 mm | Metric | 0.5079″ | 12.900 mm |
| 13.0 mm | Metric | 0.5118″ | 13.000 mm |
| 33/64″ | Fractional | 0.5156″ | 13.097 mm |
| 17/32″ | Fractional | 0.5313″ | 13.494 mm |
| 13.5 mm | Metric | 0.5315″ | 13.500 mm |
| 35/64″ | Fractional | 0.5469″ | 13.891 mm |
| 14.0 mm | Metric | 0.5512″ | 14.000 mm |
| 9/16″ | Fractional | 0.5625″ | 14.288 mm |
| 14.5 mm | Metric | 0.5709″ | 14.500 mm |
| 37/64″ | Fractional | 0.5781″ | 14.684 mm |
| 15.0 mm | Metric | 0.5906″ | 15.000 mm |
| 19/32″ | Fractional | 0.5938″ | 15.081 mm |
| 39/64″ | Fractional | 0.6094″ | 15.478 mm |
| 15.5 mm | Metric | 0.6102″ | 15.500 mm |
| 5/8″ | Fractional | 0.6250″ | 15.875 mm |
| 16.0 mm | Metric | 0.6299″ | 16.000 mm |
| 41/64″ | Fractional | 0.6406″ | 16.272 mm |
| 16.5 mm | Metric | 0.6496″ | 16.500 mm |
| 21/32″ | Fractional | 0.6563″ | 16.669 mm |
| 17.0 mm | Metric | 0.6693″ | 17.000 mm |
| 43/64″ | Fractional | 0.6719″ | 17.066 mm |
| 11/16″ | Fractional | 0.6875″ | 17.463 mm |
| 17.5 mm | Metric | 0.6890″ | 17.500 mm |
| 45/64″ | Fractional | 0.7031″ | 17.859 mm |
| 18.0 mm | Metric | 0.7087″ | 18.000 mm |
| 23/32″ | Fractional | 0.7188″ | 18.256 mm |
| 18.5 mm | Metric | 0.7283″ | 18.500 mm |
| 47/64″ | Fractional | 0.7344″ | 18.653 mm |
| 19.0 mm | Metric | 0.7480″ | 19.000 mm |
| 3/4″ | Fractional | 0.7500″ | 19.050 mm |
| 49/64″ | Fractional | 0.7656″ | 19.447 mm |
| 19.5 mm | Metric | 0.7677″ | 19.500 mm |
| 25/32″ | Fractional | 0.7813″ | 19.844 mm |
| 20.0 mm | Metric | 0.7874″ | 20.000 mm |
| 51/64″ | Fractional | 0.7969″ | 20.241 mm |
| 20.5 mm | Metric | 0.8071″ | 20.500 mm |
| 13/16″ | Fractional | 0.8125″ | 20.638 mm |
| 21.0 mm | Metric | 0.8268″ | 21.000 mm |
| 53/64″ | Fractional | 0.8281″ | 21.034 mm |
| 27/32″ | Fractional | 0.8438″ | 21.431 mm |
| 21.5 mm | Metric | 0.8465″ | 21.500 mm |
| 55/64″ | Fractional | 0.8594″ | 21.828 mm |
| 22.0 mm | Metric | 0.8661″ | 22.000 mm |
| 7/8″ | Fractional | 0.8750″ | 22.225 mm |
| 22.5 mm | Metric | 0.8858″ | 22.500 mm |
| 57/64″ | Fractional | 0.8906″ | 22.622 mm |
| 23.0 mm | Metric | 0.9055″ | 23.000 mm |
| 29/32″ | Fractional | 0.9063″ | 23.019 mm |
| 59/64″ | Fractional | 0.9219″ | 23.416 mm |
| 23.5 mm | Metric | 0.9252″ | 23.500 mm |
| 15/16″ | Fractional | 0.9375″ | 23.813 mm |
| 24.0 mm | Metric | 0.9449″ | 24.000 mm |
| 61/64″ | Fractional | 0.9531″ | 24.209 mm |
| 24.5 mm | Metric | 0.9646″ | 24.500 mm |
| 31/32″ | Fractional | 0.9688″ | 24.606 mm |
| 25.0 mm | Metric | 0.9843″ | 25.000 mm |
| 63/64″ | Fractional | 0.9844″ | 25.003 mm |
| 1″ | Fractional | 1.0000″ | 25.400 mm |
| 25.5 mm | Metric | 1.0039″ | 25.500 mm |
| 1-1/64″ | Fractional | 1.0156″ | 25.797 mm |
| 26.0 mm | Metric | 1.0236″ | 26.000 mm |
| 1-1/32″ | Fractional | 1.0313″ | 26.194 mm |
| 26.5 mm | Metric | 1.0433″ | 26.500 mm |
| 1-3/64″ | Fractional | 1.0469″ | 26.591 mm |
| 1-1/16″ | Fractional | 1.0625″ | 26.988 mm |
| 27.0 mm | Metric | 1.0630″ | 27.000 mm |
| 1-5/64″ | Fractional | 1.0781″ | 27.384 mm |
| 27.5 mm | Metric | 1.0827″ | 27.500 mm |
| 1-3/32″ | Fractional | 1.0938″ | 27.781 mm |
| 28.0 mm | Metric | 1.1024″ | 28.000 mm |
| 1-7/64″ | Fractional | 1.1094″ | 28.178 mm |
| 28.5 mm | Metric | 1.1220″ | 28.500 mm |
| 1-1/8″ | Fractional | 1.1250″ | 28.575 mm |
| 1-9/64″ | Fractional | 1.1406″ | 28.972 mm |
| 29.0 mm | Metric | 1.1417″ | 29.000 mm |
| 1-5/32″ | Fractional | 1.1563″ | 29.369 mm |
| 29.5 mm | Metric | 1.1614″ | 29.500 mm |
| 1-11/64″ | Fractional | 1.1719″ | 29.766 mm |
| 30.0 mm | Metric | 1.1811″ | 30.000 mm |
| 1-3/16″ | Fractional | 1.1875″ | 30.163 mm |
| 30.5 mm | Metric | 1.2008″ | 30.500 mm |
| 1-13/64″ | Fractional | 1.2031″ | 30.559 mm |
| 1-7/32″ | Fractional | 1.2188″ | 30.956 mm |
| 31.0 mm | Metric | 1.2205″ | 31.000 mm |
| 1-15/64″ | Fractional | 1.2344″ | 31.353 mm |
| 31.5 mm | Metric | 1.2402″ | 31.500 mm |
| 1-1/4″ | Fractional | 1.2500″ | 31.750 mm |
| 32.0 mm | Metric | 1.2598″ | 32.000 mm |
| 1-17/64″ | Fractional | 1.2656″ | 32.147 mm |
| 32.5 mm | Metric | 1.2795″ | 32.500 mm |
| 1-9/32″ | Fractional | 1.2813″ | 32.544 mm |
| 1-19/64″ | Fractional | 1.2969″ | 32.941 mm |
| 33.0 mm | Metric | 1.2992″ | 33.000 mm |
| 1-5/16″ | Fractional | 1.3125″ | 33.338 mm |
| 33.5 mm | Metric | 1.3189″ | 33.500 mm |
| 1-21/64″ | Fractional | 1.3281″ | 33.734 mm |
| 34.0 mm | Metric | 1.3386″ | 34.000 mm |
| 1-11/32″ | Fractional | 1.3438″ | 34.131 mm |
| 34.5 mm | Metric | 1.3583″ | 34.500 mm |
| 1-23/64″ | Fractional | 1.3594″ | 34.528 mm |
| 1-3/8″ | Fractional | 1.3750″ | 34.925 mm |
| 35.0 mm | Metric | 1.3780″ | 35.000 mm |
| 1-25/64″ | Fractional | 1.3906″ | 35.322 mm |
| 35.5 mm | Metric | 1.3976″ | 35.500 mm |
| 1-13/32″ | Fractional | 1.4063″ | 35.719 mm |
| 36.0 mm | Metric | 1.4173″ | 36.000 mm |
| 1-27/64″ | Fractional | 1.4219″ | 36.116 mm |
| 1-7/16″ | Fractional | 1.4375″ | 36.513 mm |
| 1-29/64″ | Fractional | 1.4531″ | 36.909 mm |
| 1-15/32″ | Fractional | 1.4688″ | 37.306 mm |
| 1-31/64″ | Fractional | 1.4844″ | 37.703 mm |
| 1-1/2″ | Fractional | 1.5000″ | 38.100 mm |
| Drill size | Type | Inches | Millimeters |
|---|---|---|---|
| #80 | Number | 0.0135″ | 0.343 mm |
| #79 | Number | 0.0145″ | 0.368 mm |
| 1/64″ | Fractional | 0.0156″ | 0.397 mm |
| #78 | Number | 0.0160″ | 0.406 mm |
| #77 | Number | 0.0180″ | 0.457 mm |
| 0.5 mm | Metric | 0.0197″ | 0.500 mm |
| #76 | Number | 0.0200″ | 0.508 mm |
| #75 | Number | 0.0210″ | 0.533 mm |
| #74 | Number | 0.0225″ | 0.572 mm |
| 0.6 mm | Metric | 0.0236″ | 0.600 mm |
| #73 | Number | 0.0240″ | 0.610 mm |
| #72 | Number | 0.0250″ | 0.635 mm |
| #71 | Number | 0.0260″ | 0.660 mm |
| 0.7 mm | Metric | 0.0276″ | 0.700 mm |
| #70 | Number | 0.0280″ | 0.711 mm |
| #69 | Number | 0.0292″ | 0.742 mm |
| #68 | Number | 0.0310″ | 0.787 mm |
| 1/32″ | Fractional | 0.0313″ | 0.794 mm |
| 0.8 mm | Metric | 0.0315″ | 0.800 mm |
| #67 | Number | 0.0320″ | 0.813 mm |
| #66 | Number | 0.0330″ | 0.838 mm |
| #65 | Number | 0.0350″ | 0.889 mm |
| 0.9 mm | Metric | 0.0354″ | 0.900 mm |
| #64 | Number | 0.0360″ | 0.914 mm |
| #63 | Number | 0.0370″ | 0.940 mm |
| #62 | Number | 0.0380″ | 0.965 mm |
| #61 | Number | 0.0390″ | 0.991 mm |
| 1.0 mm | Metric | 0.0394″ | 1.000 mm |
| #60 | Number | 0.0400″ | 1.016 mm |
| #59 | Number | 0.0410″ | 1.041 mm |
| #58 | Number | 0.0420″ | 1.067 mm |
| #57 | Number | 0.0430″ | 1.092 mm |
| 1.1 mm | Metric | 0.0433″ | 1.100 mm |
| #56 | Number | 0.0465″ | 1.181 mm |
| 3/64″ | Fractional | 0.0469″ | 1.191 mm |
| 1.2 mm | Metric | 0.0472″ | 1.200 mm |
| 1.25 mm | Metric | 0.0492″ | 1.250 mm |
| 1.3 mm | Metric | 0.0512″ | 1.300 mm |
| #55 | Number | 0.0520″ | 1.321 mm |
| #54 | Number | 0.0550″ | 1.397 mm |
| 1.4 mm | Metric | 0.0551″ | 1.400 mm |
| 1.45 mm | Metric | 0.0571″ | 1.450 mm |
| 1.5 mm | Metric | 0.0591″ | 1.500 mm |
| #53 | Number | 0.0595″ | 1.511 mm |
| 1/16″ | Fractional | 0.0625″ | 1.588 mm |
| 1.6 mm | Metric | 0.0630″ | 1.600 mm |
| #52 | Number | 0.0635″ | 1.613 mm |
| 1.7 mm | Metric | 0.0669″ | 1.700 mm |
| #51 | Number | 0.0670″ | 1.702 mm |
| 1.75 mm | Metric | 0.0689″ | 1.750 mm |
| #50 | Number | 0.0700″ | 1.778 mm |
| 1.8 mm | Metric | 0.0709″ | 1.800 mm |
| #49 | Number | 0.0730″ | 1.854 mm |
| 1.9 mm | Metric | 0.0748″ | 1.900 mm |
| #48 | Number | 0.0760″ | 1.930 mm |
| 5/64″ | Fractional | 0.0781″ | 1.984 mm |
| #47 | Number | 0.0785″ | 1.994 mm |
| 2.0 mm | Metric | 0.0787″ | 2.000 mm |
| 2.05 mm | Metric | 0.0807″ | 2.050 mm |
| #46 | Number | 0.0810″ | 2.057 mm |
| #45 | Number | 0.0820″ | 2.083 mm |
| 2.1 mm | Metric | 0.0827″ | 2.100 mm |
| #44 | Number | 0.0860″ | 2.184 mm |
| 2.2 mm | Metric | 0.0866″ | 2.200 mm |
| #43 | Number | 0.0890″ | 2.261 mm |
| 2.3 mm | Metric | 0.0906″ | 2.300 mm |
| #42 | Number | 0.0935″ | 2.375 mm |
| 3/32″ | Fractional | 0.0938″ | 2.381 mm |
| 2.4 mm | Metric | 0.0945″ | 2.400 mm |
| #41 | Number | 0.0960″ | 2.438 mm |
| #40 | Number | 0.0980″ | 2.489 mm |
| 2.5 mm | Metric | 0.0984″ | 2.500 mm |
| #39 | Number | 0.0995″ | 2.527 mm |
| #38 | Number | 0.1015″ | 2.578 mm |
| 2.6 mm | Metric | 0.1024″ | 2.600 mm |
| #37 | Number | 0.1040″ | 2.642 mm |
| 2.65 mm | Metric | 0.1043″ | 2.650 mm |
| 2.7 mm | Metric | 0.1063″ | 2.700 mm |
| #36 | Number | 0.1065″ | 2.705 mm |
| 7/64″ | Fractional | 0.1094″ | 2.778 mm |
| #35 | Number | 0.1100″ | 2.794 mm |
| 2.8 mm | Metric | 0.1102″ | 2.800 mm |
| #34 | Number | 0.1110″ | 2.819 mm |
| #33 | Number | 0.1130″ | 2.870 mm |
| 2.9 mm | Metric | 0.1142″ | 2.900 mm |
| #32 | Number | 0.1160″ | 2.946 mm |
| 3.0 mm | Metric | 0.1181″ | 3.000 mm |
| #31 | Number | 0.1200″ | 3.048 mm |
| 3.1 mm | Metric | 0.1220″ | 3.100 mm |
| 1/8″ | Fractional | 0.1250″ | 3.175 mm |
| 3.2 mm | Metric | 0.1260″ | 3.200 mm |
| #30 | Number | 0.1285″ | 3.264 mm |
| 3.3 mm | Metric | 0.1299″ | 3.300 mm |
| 3.4 mm | Metric | 0.1339″ | 3.400 mm |
| #29 | Number | 0.1360″ | 3.454 mm |
| 3.5 mm | Metric | 0.1378″ | 3.500 mm |
| #28 | Number | 0.1405″ | 3.569 mm |
| 9/64″ | Fractional | 0.1406″ | 3.572 mm |
| 3.6 mm | Metric | 0.1417″ | 3.600 mm |
| #27 | Number | 0.1440″ | 3.658 mm |
| 3.7 mm | Metric | 0.1457″ | 3.700 mm |
| #26 | Number | 0.1470″ | 3.734 mm |
| 3.75 mm | Metric | 0.1476″ | 3.750 mm |
| #25 | Number | 0.1495″ | 3.797 mm |
| 3.8 mm | Metric | 0.1496″ | 3.800 mm |
| #24 | Number | 0.1520″ | 3.861 mm |
| 3.9 mm | Metric | 0.1535″ | 3.900 mm |
| #23 | Number | 0.1540″ | 3.912 mm |
| 5/32″ | Fractional | 0.1563″ | 3.969 mm |
| #22 | Number | 0.1570″ | 3.988 mm |
| 4.0 mm | Metric | 0.1575″ | 4.000 mm |
| #21 | Number | 0.1590″ | 4.039 mm |
| #20 | Number | 0.1610″ | 4.089 mm |
| 4.1 mm | Metric | 0.1614″ | 4.100 mm |
| 4.2 mm | Metric | 0.1654″ | 4.200 mm |
| #19 | Number | 0.1660″ | 4.216 mm |
| 4.3 mm | Metric | 0.1693″ | 4.300 mm |
| #18 | Number | 0.1695″ | 4.305 mm |
| 11/64″ | Fractional | 0.1719″ | 4.366 mm |
| #17 | Number | 0.1730″ | 4.394 mm |
| 4.4 mm | Metric | 0.1732″ | 4.400 mm |
| #16 | Number | 0.1770″ | 4.496 mm |
| 4.5 mm | Metric | 0.1772″ | 4.500 mm |
| #15 | Number | 0.1800″ | 4.572 mm |
| 4.6 mm | Metric | 0.1811″ | 4.600 mm |
| #14 | Number | 0.1820″ | 4.623 mm |
| #13 | Number | 0.1850″ | 4.699 mm |
| 4.7 mm | Metric | 0.1850″ | 4.700 mm |
| 3/16″ | Fractional | 0.1875″ | 4.763 mm |
| 4.8 mm | Metric | 0.1890″ | 4.800 mm |
| #12 | Number | 0.1890″ | 4.801 mm |
| #11 | Number | 0.1910″ | 4.851 mm |
| 4.9 mm | Metric | 0.1929″ | 4.900 mm |
| #10 | Number | 0.1935″ | 4.915 mm |
| #9 | Number | 0.1960″ | 4.978 mm |
| 5.0 mm | Metric | 0.1969″ | 5.000 mm |
| #8 | Number | 0.1990″ | 5.055 mm |
| 5.1 mm | Metric | 0.2008″ | 5.100 mm |
| #7 | Number | 0.2010″ | 5.105 mm |
| 13/64″ | Fractional | 0.2031″ | 5.159 mm |
| #6 | Number | 0.2040″ | 5.182 mm |
| 5.2 mm | Metric | 0.2047″ | 5.200 mm |
| #5 | Number | 0.2055″ | 5.220 mm |
| 5.25 mm | Metric | 0.2067″ | 5.250 mm |
| 5.3 mm | Metric | 0.2087″ | 5.300 mm |
| #4 | Number | 0.2090″ | 5.309 mm |
| 5.4 mm | Metric | 0.2126″ | 5.400 mm |
| #3 | Number | 0.2130″ | 5.410 mm |
| 5.5 mm | Metric | 0.2165″ | 5.500 mm |
| 7/32″ | Fractional | 0.2188″ | 5.556 mm |
| 5.6 mm | Metric | 0.2205″ | 5.600 mm |
| #2 | Number | 0.2210″ | 5.613 mm |
| 5.7 mm | Metric | 0.2244″ | 5.700 mm |
| #1 | Number | 0.2280″ | 5.791 mm |
| 5.8 mm | Metric | 0.2283″ | 5.800 mm |
| 5.9 mm | Metric | 0.2323″ | 5.900 mm |
| A | Letter | 0.2340″ | 5.944 mm |
| 15/64″ | Fractional | 0.2344″ | 5.953 mm |
| 6.0 mm | Metric | 0.2362″ | 6.000 mm |
| B | Letter | 0.2380″ | 6.045 mm |
| 6.1 mm | Metric | 0.2402″ | 6.100 mm |
| C | Letter | 0.2420″ | 6.147 mm |
| 6.2 mm | Metric | 0.2441″ | 6.200 mm |
| D | Letter | 0.2460″ | 6.248 mm |
| 6.3 mm | Metric | 0.2480″ | 6.300 mm |
| E | Letter | 0.2500″ | 6.350 mm |
| 1/4″ | Fractional | 0.2500″ | 6.350 mm |
| 6.4 mm | Metric | 0.2520″ | 6.400 mm |
| 6.5 mm | Metric | 0.2559″ | 6.500 mm |
| F | Letter | 0.2570″ | 6.528 mm |
| 6.6 mm | Metric | 0.2598″ | 6.600 mm |
| G | Letter | 0.2610″ | 6.629 mm |
| 6.7 mm | Metric | 0.2638″ | 6.700 mm |
| 17/64″ | Fractional | 0.2656″ | 6.747 mm |
| H | Letter | 0.2660″ | 6.756 mm |
| 6.8 mm | Metric | 0.2677″ | 6.800 mm |
| 6.9 mm | Metric | 0.2717″ | 6.900 mm |
| I | Letter | 0.2720″ | 6.909 mm |
| 7.0 mm | Metric | 0.2756″ | 7.000 mm |
| J | Letter | 0.2770″ | 7.036 mm |
| 7.1 mm | Metric | 0.2795″ | 7.100 mm |
| K | Letter | 0.2810″ | 7.137 mm |
| 9/32″ | Fractional | 0.2813″ | 7.144 mm |
| 7.2 mm | Metric | 0.2835″ | 7.200 mm |
| 7.3 mm | Metric | 0.2874″ | 7.300 mm |
| L | Letter | 0.2900″ | 7.366 mm |
| 7.4 mm | Metric | 0.2913″ | 7.400 mm |
| M | Letter | 0.2950″ | 7.493 mm |
| 7.5 mm | Metric | 0.2953″ | 7.500 mm |
| 19/64″ | Fractional | 0.2969″ | 7.541 mm |
| 7.6 mm | Metric | 0.2992″ | 7.600 mm |
| N | Letter | 0.3020″ | 7.671 mm |
| 7.7 mm | Metric | 0.3031″ | 7.700 mm |
| 7.8 mm | Metric | 0.3071″ | 7.800 mm |
| 7.9 mm | Metric | 0.3110″ | 7.900 mm |
| 5/16″ | Fractional | 0.3125″ | 7.938 mm |
| 8.0 mm | Metric | 0.3150″ | 8.000 mm |
| O | Letter | 0.3160″ | 8.026 mm |
| 8.1 mm | Metric | 0.3189″ | 8.100 mm |
| 8.2 mm | Metric | 0.3228″ | 8.200 mm |
| P | Letter | 0.3230″ | 8.204 mm |
| 8.3 mm | Metric | 0.3268″ | 8.300 mm |
| 21/64″ | Fractional | 0.3281″ | 8.334 mm |
| 8.4 mm | Metric | 0.3307″ | 8.400 mm |
| Q | Letter | 0.3320″ | 8.433 mm |
| 8.5 mm | Metric | 0.3346″ | 8.500 mm |
| 8.6 mm | Metric | 0.3386″ | 8.600 mm |
| R | Letter | 0.3390″ | 8.611 mm |
| 8.7 mm | Metric | 0.3425″ | 8.700 mm |
| 11/32″ | Fractional | 0.3438″ | 8.731 mm |
| 8.75 mm | Metric | 0.3445″ | 8.750 mm |
| 8.8 mm | Metric | 0.3465″ | 8.800 mm |
| S | Letter | 0.3480″ | 8.839 mm |
| 8.9 mm | Metric | 0.3504″ | 8.900 mm |
| 9.0 mm | Metric | 0.3543″ | 9.000 mm |
| T | Letter | 0.3580″ | 9.093 mm |
| 9.1 mm | Metric | 0.3583″ | 9.100 mm |
| 23/64″ | Fractional | 0.3594″ | 9.128 mm |
| 9.2 mm | Metric | 0.3622″ | 9.200 mm |
| 9.3 mm | Metric | 0.3661″ | 9.300 mm |
| U | Letter | 0.3680″ | 9.347 mm |
| 9.4 mm | Metric | 0.3701″ | 9.400 mm |
| 9.5 mm | Metric | 0.3740″ | 9.500 mm |
| 3/8″ | Fractional | 0.3750″ | 9.525 mm |
| V | Letter | 0.3770″ | 9.576 mm |
| 9.6 mm | Metric | 0.3780″ | 9.600 mm |
| 9.7 mm | Metric | 0.3819″ | 9.700 mm |
| 9.8 mm | Metric | 0.3858″ | 9.800 mm |
| W | Letter | 0.3860″ | 9.804 mm |
| 9.9 mm | Metric | 0.3898″ | 9.900 mm |
| 25/64″ | Fractional | 0.3906″ | 9.922 mm |
| 10.0 mm | Metric | 0.3937″ | 10.000 mm |
| X | Letter | 0.3970″ | 10.084 mm |
| 10.1 mm | Metric | 0.3976″ | 10.100 mm |
| 10.2 mm | Metric | 0.4016″ | 10.200 mm |
| Y | Letter | 0.4040″ | 10.262 mm |
| 10.3 mm | Metric | 0.4055″ | 10.300 mm |
| 13/32″ | Fractional | 0.4063″ | 10.319 mm |
| 10.4 mm | Metric | 0.4094″ | 10.400 mm |
| Z | Letter | 0.4130″ | 10.490 mm |
| 10.5 mm | Metric | 0.4134″ | 10.500 mm |
| 10.6 mm | Metric | 0.4173″ | 10.600 mm |
| 10.7 mm | Metric | 0.4213″ | 10.700 mm |
| 27/64″ | Fractional | 0.4219″ | 10.716 mm |
| 10.75 mm | Metric | 0.4232″ | 10.750 mm |
| 10.8 mm | Metric | 0.4252″ | 10.800 mm |
| 10.9 mm | Metric | 0.4291″ | 10.900 mm |
| 11.0 mm | Metric | 0.4331″ | 11.000 mm |
| 11.1 mm | Metric | 0.4370″ | 11.100 mm |
| 7/16″ | Fractional | 0.4375″ | 11.113 mm |
| 11.2 mm | Metric | 0.4409″ | 11.200 mm |
| 11.3 mm | Metric | 0.4449″ | 11.300 mm |
| 11.4 mm | Metric | 0.4488″ | 11.400 mm |
| 11.5 mm | Metric | 0.4528″ | 11.500 mm |
| 29/64″ | Fractional | 0.4531″ | 11.509 mm |
| 11.6 mm | Metric | 0.4567″ | 11.600 mm |
| 11.7 mm | Metric | 0.4606″ | 11.700 mm |
| 11.8 mm | Metric | 0.4646″ | 11.800 mm |
| 11.9 mm | Metric | 0.4685″ | 11.900 mm |
| 15/32″ | Fractional | 0.4688″ | 11.906 mm |
| 12.0 mm | Metric | 0.4724″ | 12.000 mm |
| 12.1 mm | Metric | 0.4764″ | 12.100 mm |
| 12.2 mm | Metric | 0.4803″ | 12.200 mm |
| 12.3 mm | Metric | 0.4843″ | 12.300 mm |
| 31/64″ | Fractional | 0.4844″ | 12.303 mm |
| 12.4 mm | Metric | 0.4882″ | 12.400 mm |
| 12.5 mm | Metric | 0.4921″ | 12.500 mm |
| 12.6 mm | Metric | 0.4961″ | 12.600 mm |
| 1/2″ | Fractional | 0.5000″ | 12.700 mm |
| 12.7 mm | Metric | 0.5000″ | 12.700 mm |
| 12.8 mm | Metric | 0.5039″ | 12.800 mm |
| 12.9 mm | Metric | 0.5079″ | 12.900 mm |
| 13.0 mm | Metric | 0.5118″ | 13.000 mm |
| 33/64″ | Fractional | 0.5156″ | 13.097 mm |
| 17/32″ | Fractional | 0.5313″ | 13.494 mm |
| 13.5 mm | Metric | 0.5315″ | 13.500 mm |
| 35/64″ | Fractional | 0.5469″ | 13.891 mm |
| 14.0 mm | Metric | 0.5512″ | 14.000 mm |
| 9/16″ | Fractional | 0.5625″ | 14.288 mm |
| 14.5 mm | Metric | 0.5709″ | 14.500 mm |
| 37/64″ | Fractional | 0.5781″ | 14.684 mm |
| 15.0 mm | Metric | 0.5906″ | 15.000 mm |
| 19/32″ | Fractional | 0.5938″ | 15.081 mm |
| 39/64″ | Fractional | 0.6094″ | 15.478 mm |
| 15.5 mm | Metric | 0.6102″ | 15.500 mm |
| 5/8″ | Fractional | 0.6250″ | 15.875 mm |
| 16.0 mm | Metric | 0.6299″ | 16.000 mm |
| 41/64″ | Fractional | 0.6406″ | 16.272 mm |
| 16.5 mm | Metric | 0.6496″ | 16.500 mm |
| 21/32″ | Fractional | 0.6563″ | 16.669 mm |
| 17.0 mm | Metric | 0.6693″ | 17.000 mm |
| 43/64″ | Fractional | 0.6719″ | 17.066 mm |
| 11/16″ | Fractional | 0.6875″ | 17.463 mm |
| 17.5 mm | Metric | 0.6890″ | 17.500 mm |
| 45/64″ | Fractional | 0.7031″ | 17.859 mm |
| 18.0 mm | Metric | 0.7087″ | 18.000 mm |
| 23/32″ | Fractional | 0.7188″ | 18.256 mm |
| 18.5 mm | Metric | 0.7283″ | 18.500 mm |
| 47/64″ | Fractional | 0.7344″ | 18.653 mm |
| 19.0 mm | Metric | 0.7480″ | 19.000 mm |
| 3/4″ | Fractional | 0.7500″ | 19.050 mm |
| 49/64″ | Fractional | 0.7656″ | 19.447 mm |
| 19.5 mm | Metric | 0.7677″ | 19.500 mm |
| 25/32″ | Fractional | 0.7813″ | 19.844 mm |
| 20.0 mm | Metric | 0.7874″ | 20.000 mm |
| 51/64″ | Fractional | 0.7969″ | 20.241 mm |
| 20.5 mm | Metric | 0.8071″ | 20.500 mm |
| 13/16″ | Fractional | 0.8125″ | 20.638 mm |
| 21.0 mm | Metric | 0.8268″ | 21.000 mm |
| 53/64″ | Fractional | 0.8281″ | 21.034 mm |
| 27/32″ | Fractional | 0.8438″ | 21.431 mm |
| 21.5 mm | Metric | 0.8465″ | 21.500 mm |
| 55/64″ | Fractional | 0.8594″ | 21.828 mm |
| 22.0 mm | Metric | 0.8661″ | 22.000 mm |
| 7/8″ | Fractional | 0.8750″ | 22.225 mm |
| 22.5 mm | Metric | 0.8858″ | 22.500 mm |
| 57/64″ | Fractional | 0.8906″ | 22.622 mm |
| 23.0 mm | Metric | 0.9055″ | 23.000 mm |
| 29/32″ | Fractional | 0.9063″ | 23.019 mm |
| 59/64″ | Fractional | 0.9219″ | 23.416 mm |
| 23.5 mm | Metric | 0.9252″ | 23.500 mm |
| 15/16″ | Fractional | 0.9375″ | 23.813 mm |
| 24.0 mm | Metric | 0.9449″ | 24.000 mm |
| 61/64″ | Fractional | 0.9531″ | 24.209 mm |
| 24.5 mm | Metric | 0.9646″ | 24.500 mm |
| 31/32″ | Fractional | 0.9688″ | 24.606 mm |
| 25.0 mm | Metric | 0.9843″ | 25.000 mm |
| 63/64″ | Fractional | 0.9844″ | 25.003 mm |
| 1″ | Fractional | 1.0000″ | 25.400 mm |
| 25.5 mm | Metric | 1.0039″ | 25.500 mm |
| 1-1/64″ | Fractional | 1.0156″ | 25.797 mm |
| 26.0 mm | Metric | 1.0236″ | 26.000 mm |
| 1-1/32″ | Fractional | 1.0313″ | 26.194 mm |
| 26.5 mm | Metric | 1.0433″ | 26.500 mm |
| 1-3/64″ | Fractional | 1.0469″ | 26.591 mm |
| 1-1/16″ | Fractional | 1.0625″ | 26.988 mm |
| 27.0 mm | Metric | 1.0630″ | 27.000 mm |
| 1-5/64″ | Fractional | 1.0781″ | 27.384 mm |
| 27.5 mm | Metric | 1.0827″ | 27.500 mm |
| 1-3/32″ | Fractional | 1.0938″ | 27.781 mm |
| 28.0 mm | Metric | 1.1024″ | 28.000 mm |
| 1-7/64″ | Fractional | 1.1094″ | 28.178 mm |
| 28.5 mm | Metric | 1.1220″ | 28.500 mm |
| 1-1/8″ | Fractional | 1.1250″ | 28.575 mm |
| 1-9/64″ | Fractional | 1.1406″ | 28.972 mm |
| 29.0 mm | Metric | 1.1417″ | 29.000 mm |
| 1-5/32″ | Fractional | 1.1563″ | 29.369 mm |
| 29.5 mm | Metric | 1.1614″ | 29.500 mm |
| 1-11/64″ | Fractional | 1.1719″ | 29.766 mm |
| 30.0 mm | Metric | 1.1811″ | 30.000 mm |
| 1-3/16″ | Fractional | 1.1875″ | 30.163 mm |
| 30.5 mm | Metric | 1.2008″ | 30.500 mm |
| 1-13/64″ | Fractional | 1.2031″ | 30.559 mm |
| 1-7/32″ | Fractional | 1.2188″ | 30.956 mm |
| 31.0 mm | Metric | 1.2205″ | 31.000 mm |
| 1-15/64″ | Fractional | 1.2344″ | 31.353 mm |
| 31.5 mm | Metric | 1.2402″ | 31.500 mm |
| 1-1/4″ | Fractional | 1.2500″ | 31.750 mm |
| 32.0 mm | Metric | 1.2598″ | 32.000 mm |
| 1-17/64″ | Fractional | 1.2656″ | 32.147 mm |
| 32.5 mm | Metric | 1.2795″ | 32.500 mm |
| 1-9/32″ | Fractional | 1.2813″ | 32.544 mm |
| 1-19/64″ | Fractional | 1.2969″ | 32.941 mm |
| 33.0 mm | Metric | 1.2992″ | 33.000 mm |
| 1-5/16″ | Fractional | 1.3125″ | 33.338 mm |
| 33.5 mm | Metric | 1.3189″ | 33.500 mm |
| 1-21/64″ | Fractional | 1.3281″ | 33.734 mm |
| 34.0 mm | Metric | 1.3386″ | 34.000 mm |
| 1-11/32″ | Fractional | 1.3438″ | 34.131 mm |
| 34.5 mm | Metric | 1.3583″ | 34.500 mm |
| 1-23/64″ | Fractional | 1.3594″ | 34.528 mm |
| 1-3/8″ | Fractional | 1.3750″ | 34.925 mm |
| 35.0 mm | Metric | 1.3780″ | 35.000 mm |
| 1-25/64″ | Fractional | 1.3906″ | 35.322 mm |
| 35.5 mm | Metric | 1.3976″ | 35.500 mm |
| 1-13/32″ | Fractional | 1.4063″ | 35.719 mm |
| 36.0 mm | Metric | 1.4173″ | 36.000 mm |
| 1-27/64″ | Fractional | 1.4219″ | 36.116 mm |
| 1-7/16″ | Fractional | 1.4375″ | 36.513 mm |
| 1-29/64″ | Fractional | 1.4531″ | 36.909 mm |
| 1-15/32″ | Fractional | 1.4688″ | 37.306 mm |
| 1-31/64″ | Fractional | 1.4844″ | 37.703 mm |
| 1-1/2″ | Fractional | 1.5000″ | 38.100 mm |
Nominal sizes may coincide across series (for example, E and 1/4″ are both 0.2500″). The equivalent columns convert diameter; they are not substitutions for tap or clearance-hole recommendations. Metric series is a practical shop index, not an exhaustive manufacturer-stock list.
SAE (47 rows) and metric (50 rows) remain reviewed cutting-tap references. The complete drill-size index adds nominal drill dimensions and exact converted equivalents, not additional tap recommendations. These are not certified hole-size specifications or toolmaker approvals. Final paid PDFs, print sizes, and machine-specific use still require release checks.
Start with the existing thread. Remove contamination first; use a matched chaser only when needed. Cleaning and chasing cannot replace missing metal or prove a joint is safe.
For existing tapped holes contaminated by debris, oil, residue, or light corrosion.
Open a reference when you need the details. These apply alongside the procedure above.
Identify the contamination and workpiece material first. Use a cleaner approved for the metal, plating, seals, paint and nearby components. Remove loosened debris and residue rather than allowing it to collect inside the hole.
Old cured threadlocker may need careful mechanical removal and solvent treatment according to the adhesive manufacturer's instructions. Before applying new threadlocker, follow its product-specific surface-preparation requirements; oils or cleaning residues can affect bonding.
Reference: LOCTITE — Surface preparation for threadlockers ↗
A correctly sized chaser follows the original diameter and pitch and is intended for cleaning or slight thread-form restoration. Start squarely and stop if it binds unexpectedly.
Standard cutting taps and dies can remove parent material. They are not the default choice for routine cleaning, though an individual manufacturer's repair or installation instructions may explicitly call for a specified tap. Never substitute an oversized tool to make a fastener fit.
Reference: ARP Fastener Installation FAQ — thread preparation ↗
Blind holes can collect chips and trapped liquids. Before assembly, remove pooled oil or cleaner, check usable thread depth, and confirm the fastener cannot bottom before clamping the joint. Final lubrication or sealant still depends on the manufacturer's assembly instructions; not every installation calls for dry threads.
Prefer controlled extraction, swabs or suitable vacuum methods for loose material. If compressed air is used for cleaning in a workplace covered by OSHA's general-industry rule, it must be reduced to less than 30 psi with effective chip guarding and appropriate PPE. Do not aim air at yourself or bystanders.
References: Fel-Pro — TTY bolt installation ↗ · OSHA 1910.242(b) ↗
Inspect thread crests, flanks, corrosion, cracks, missing metal and damaged protective coatings. A correct fastener threading in freely by hand is a helpful check for gross interference, not proof of fastener strength, adequate engagement or joint safety.
Do not reuse fasteners the manufacturer identifies as single-use, or fasteners that fail specified dimensional or condition checks. Torque-to-yield head bolts are a common replacement-only example. Verify the assembly's specified lubricated, sealed or dry condition before tightening.
Reference: Fel-Pro — TTY bolt service ↗
Stop and inspect the joint or follow the specified repair procedure when you find:
Material is gone, the thread form is substantially damaged, or normal engagement cannot be achieved.
A bolt or stud is stretched, cracked, severely corroded, or specified as single-use.
The repair affects a critical assembly or the fastener does not seat and engage as specified.
Cleaning does not restore missing thread material or certify load capacity. Use an approved repair and verify the joint's service requirements.
Inspect the cleaned thread form and confirm the correct fastener engages smoothly by hand. Follow the assembly-specific lubrication, sealing, tightening and reuse instructions.
First identify the damage. Cleaning, thread restoration, oversizing and installing a threaded insert address different conditions. The right repair depends on the parent material, hole geometry and assembly requirements.
Assess the entry threads, working thread engagement and mating fastener before choosing a repair.
Check the repair against the applicable specifications for fit, alignment, engagement and inspection.
A thread chaser follows existing thread form to remove deposits or correct light deformation without intentionally cutting a new profile. A cutting tap removes material. If the original threads are sound, use the Cleaning guide; if material is missing, a tap or chaser cannot put it back.
Controlled original-size retapping may be acceptable for specific minor damage, but only when the remaining engagement and repair method meet the actual application's requirements. Avoid using the TapBase cutting-tap chart as a repair instruction.
Reference: ARP fastener installation guidance ↗
A wire insert can restore the original bolt thread size by using a larger, specially prepared receiving thread in the damaged component. This is not the same as drilling for a larger bolt. Confirm material, edge distance, wall thickness, hole depth, thread pitch and insert length.
Follow the selected insert system's specified drill, special insert-receiving tap, installation depth and installation method. For tang-type inserts, follow that system's tang-removal instructions. A standard cutting-tap drill chart is not the setup chart for an insert.
Reference: Böllhoff HELICOIL repair and installation handbook (PDF) ↗
Solid inserts use a machined bushing rather than a wire coil. The selected system can call for drilling, counterboring, a dedicated tap and an installation driver. Do not assume every solid insert uses the same steps or retention mechanism.
Blind holes need enough usable depth for the insert and the manufacturer's cutting and installation tools. Check the kit's required clearance, tool bottoming limits, debris removal, insert seating and locking method before assembly.
Reference: TIME-SERT installation FAQ ↗
Changing to a larger bolt changes the fastener, joint geometry and potentially the clamp-load design. Oversize tapping is appropriate only when the assembly is designed or formally approved for the changed fastener and enough sound parent material remains.
If an existing wire or solid insert has failed, identify the repair already present before machining. Dedicated oversize insert systems are available for some previous repairs, but not every damaged hole has sufficient remaining material. Verify the particular kit and application, rather than stacking repairs automatically.
Reference: TIME-SERT BIG-SERT oversized repairs ↗
We’re preparing downloadable SAE, metric, and drill-size reference sheets. The online charts and lookup tools are available now, free to use.
A planned collection bringing SAE and metric tap-drill references together with the drill-size index. The final contents and format are still being developed.
| THREAD | DRILL | INCH |
|---|---|---|
| 1/4–20 | #7 | .2010 |
| 5/16–18 | F | .2570 |
| 3/8–16 | 5/16 | .3125 |
| 1/4–28 | #3 | .2130 |
A bench-friendly reference for common UNC and UNF thread sizes, recommended tap drills, and decimal-inch equivalents.
| THREAD | DRILL | INCH |
|---|---|---|
| M5 × 0.8 | 4.2 | .1654 |
| M6 × 1.0 | 5.0 | .1969 |
| M8 × 1.25 | 6.8 | .2677 |
| M10 × 1.5 | 8.5 | .3346 |
Covers common metric coarse and fine threads, with thread pitch, recommended tap drills, and decimal-inch equivalents.
| DRILL | INCH | MM |
|---|---|---|
| #7 | .2010 | 5.105 |
| F | .2570 | 6.528 |
| 5/16 | .3125 | 7.938 |
| 5.0 mm | .1969 | 5.000 |
A compact conversion sheet for number, letter, fractional, and metric drill sizes—useful alongside the tap-drill charts or anywhere drill designations need translating fast.
Both tools produce internal threads, but use different processes. A cutting tap shears material away; a forming (roll) tap plastically displaces suitably ductile material. The tool, starting-hole diameter, lubrication and material requirements are different.
A cutting tap uses cutting edges to shear metal into chips. Its flute and chamfer geometry help control chip flow as the thread is produced.
A forming (roll) tap uses rounded lobes to displace ductile material into an internal thread profile without generating cutting chips.
Conceptual cutaway diagrams only — not to scale, and not a depiction of specific tap tooth geometry or thread tolerances.
TapBase's general tap-drill charts contain common cutting-tap starting sizes. Do not use those diameters for a forming tap. Follow the specific tap manufacturer's hole-size range for the thread tolerance, material and target engagement; check the actual drilled hole, not only the drill label.
Confirm thread diameter, pitch, standard and tolerance class; identify the exact cutting or forming tap.
Check the actual hole diameter, tolerance, depth and entry chamfer; allow clearance in blind holes.
Match tap geometry, alignment and lubricant to the material and hole type; plan chip evacuation for cutting taps.
| CONSIDERATION | CUTTING TAP | FORMING TAP |
|---|---|---|
| How the thread is made | Cutting edges shear workpiece material to create the internal thread profile. | Forming lobes plastically displace compatible ductile material into the thread profile. |
| Chips | Generates chips; correct flute geometry and chip direction matter, especially in blind holes. | Does not generate cutting chips while forming the thread. |
| Starting hole | Use the specified starting-hole diameter for the cutting tap, tolerance and application. | Usually a larger starting hole than a cutting tap; tightly controlled to manufacturer data. |
| Material suitability | Suitable for many material groups when geometry, coating and cutting conditions are appropriate. | Requires compatible material ductility; brittle or unsuitable materials should not be form-tapped. |
| Lubrication | Use the specified cutting fluid or approved dry-tapping process; chip control remains important. | High contact pressure makes the manufacturer-recommended lubricant especially important. |
| Through vs. blind holes | Select flute/chamfer geometry for hole type and intended chip direction; provide chip-clearance room in blind holes. | Chipless forming can be useful for blind holes, but tap entry, depth and lubricant delivery still matter. |
| Inspection | Check the finished thread to its specified class using suitable thread gauges or the service procedure. | Check the formed thread to its specified class; the final minor diameter changes as material flows. |
| Common problems | Chip packing or incorrect flow, wrong hole size, misalignment and tool damage. | Incorrect starting-hole diameter, incompatible material, high torque or inadequate lubrication. |
No. A common cutting-tap chart is not a forming-tap drill chart. Use the forming-tool maker's hole-size range for the exact thread, material and required tolerance.
Often, yes, in suitable ductile aluminum alloys. The alloy, temper, tool geometry, lubrication and application matter; verify the exact material against the tap maker's recommendations.
No. Chipless does not mean frictionless. Forming requires suitable lubrication or a specifically approved process to control friction, torque and tool life.
No. A forming tap is designed to produce new threads in a prepared hole, not chase or clean existing threads. Use the Cleaning or Repair guide for an existing threaded hole.
Sometimes, depending on tool design. Cutting taps have different flute and chamfer geometries that change chip direction and usable thread depth. A suitable forming tap may work in either hole type, but hole depth, tool design and lubricant delivery must still be checked.
Measure or gauge the finished thread against the required tolerance class and service specification. Smooth engagement by hand alone does not prove thread accuracy or strength.
This guide compares general cutting and forming methods; it is not a substitute for the exact tool maker's drilling, tapping and inspection data. Verify the workpiece alloy, tool specification, tolerance class, actual hole size and cutting or forming conditions for your application.
Tap-drill size does not determine tightening torque. For a separate general reference, see TorqueBase’s SAE and metric bolt torque charts. Use the joint’s specified tightening procedure when available.