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Dowel pins, inch (ASME B18.8.2 hardened ground machine dowel pins), 1/16 to 1 in: standard and oversize diameter limits, point diameter, crown

What are the standard and oversize diameter limits of a 1/4 in dowel pin (ASME B18.8.2)? · Standard part · basis: Engineers Edge's ASME B18.8.2 table, checked against the Machinery's Handbook pocket companion table (1/16 to 1/2 in agree on every value read; its 5/8 in row is cut off); numbers only

Also called: asme b18.8.2 dowel pin, 1/4 dowel pin diameter, 1/4 inch dowel pin size .2503, oversize dowel pin .0008, 1/8 dowel pin diameter tolerance, 3/8 dowel pin diameter, dowel pin sizes inch chart, hardened ground machine dowel pin, 5/16 dowel pin diameter, 1/2 dowel pin .5003, standard series vs oversize dowel pin

Exact dimensions. True size, with no tolerance added.

sizes
15 in table

Notes

  • Hardened ground machine dowel pins, ASME B18.8.2, inch, nominal 1/16 to 1 in. Each size has two diameter series: the standard series (for initial installation) and the oversize series (0.0008 in larger, for replacement pins in worn holes), each with a 0.0002 in limit band. Columns: pin diameter max / min for each series in inches (as printed) and in mm (computed, x 25.4), point diameter B max / min and the crown value C max / min, all in inches. Engineers Edge's heading for the last pair is 'crown height C / crown radius R' without saying which the printed column is, so the column is labelled C (crown) and not read further; the Machinery's Handbook text prints the same numbers. The 5/32 in nominal is missing in Engineers Edge's size column and was read from the diameters (0.1565 / 0.1563 in) in both sources.
  • Length tolerance is ±0.010 in (Engineers Edge's footnote; Amesweb's ASME B18.8.2-2000 page prints the same). Nominal lengths run in 1/16 in steps up to 3/8 in, then 1/8 in, 1/4 in and 1/2 in steps per Engineers Edge's footnote b; the per-size length table was not on the page. The Machinery's Handbook text also prints a double-shear column and a suggested hole range; the column labels did not survive the text extraction, so those values are left out.
  • Oversize series diameters are exactly 0.0008 in above the standard series (max and min) on every row read. For a nominal 1/4 in pin that is Ø6.358 / 6.353 mm standard against Ø6.378 / 6.373 mm oversize (computed).
  • Not on this page: unhardened dowel pins, pull-out (tapped) dowels and the metric ISO series (dowel-pins-iso-2338-8734). No file: a dowel is a cylinder with a chamfer or crown, a plain primitive, and the crown height and radius are not separated in the source read.
  • The existing page dowel-pins-metric covers 2 to 6 mm metric dowels at press and slip hole sizes.

Dowel pins, inch (ASME B18.8.2 hardened ground machine dowel pins)… size chart

nominal sizestandard series max / min (in)standard series max / min (mm, computed)oversize series max / min (in)oversize series max / min (mm, computed)point diameter B max / min (in)crown C max / min (in)
1/16 in0.0628 / 0.06261.595 / 1.5900.0636 / 0.06341.615 / 1.6100.058 / 0.0480.020 / 0.008
5/64 in0.0784 / 0.07821.991 / 1.9860.0792 / 0.07902.012 / 2.0070.074 / 0.0640.026 / 0.010
3/32 in0.0941 / 0.09392.390 / 2.3850.0949 / 0.09472.410 / 2.4050.089 / 0.0790.031 / 0.012
1/8 in0.1253 / 0.12513.183 / 3.1780.1261 / 0.12593.203 / 3.1980.120 / 0.1100.041 / 0.016
5/32 in0.1565 / 0.15633.975 / 3.9700.1573 / 0.15713.995 / 3.9900.150 / 0.1400.052 / 0.020
3/16 in0.1878 / 0.18764.770 / 4.7650.1886 / 0.18844.790 / 4.7850.180 / 0.1700.062 / 0.023
1/4 in0.2503 / 0.25016.358 / 6.3530.2511 / 0.25096.378 / 6.3730.240 / 0.2300.083 / 0.031
5/16 in0.3128 / 0.31267.945 / 7.9400.3136 / 0.31347.965 / 7.9600.302 / 0.2900.104 / 0.039
3/8 in0.3753 / 0.37519.533 / 9.5280.3761 / 0.37599.553 / 9.5480.365 / 0.3500.125 / 0.047
7/16 in0.4378 / 0.437611.120 / 11.1150.4386 / 0.438411.140 / 11.1350.424 / 0.4090.146 / 0.055
1/2 in0.5003 / 0.500112.708 / 12.7030.5011 / 0.500912.728 / 12.7230.486 / 0.4710.167 / 0.063
5/8 in0.6253 / 0.625115.883 / 15.8780.6261 / 0.625915.903 / 15.8980.611 / 0.5950.208 / 0.078
3/4 in0.7503 / 0.750119.058 / 19.0530.7511 / 0.750919.078 / 19.0730.735 / 0.7150.250 / 0.094
7/8 in0.8753 / 0.875122.233 / 22.2280.8761 / 0.875922.253 / 22.2480.860 / 0.8400.293 / 0.109
1 in1.0003 / 1.000125.408 / 25.4031.0011 / 1.000925.428 / 25.4230.980 / 0.9600.333 / 0.125

Where the files are

Other publishers' files are linked, not hosted. "verify" = check the license at the link before commercial use.

Engineers EdgeANSI / ASME B18.8.2 hardened ground machine dowel pins: standard and oversize series diameter max / min, point diameter B, crown, length footnote, 1/16 to 1 inwebReference page; numbers only
Machinery's Handbook pocket companion (GlobalSpec reference)Dowel pins: nominal size, standard and oversize limits, point B, crown, 1/16 to 5/8 in (cross-check; OCR)webReference text; numbers only
AmeswebDowel pins dimensions (inch): ASME B18.8.2-2000 calculator; length tolerance ±0.01 in (values are interactive and were not readable)webReference page; numbers only
MISUMIDowel pins, spring pins, stepped pins (configure a part and download 3D CAD from MISUMI)web, CADMaker site terms; CAD per part from the maker verify

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Plain text: sheet.txt · JSON: /api/geometry?object=dowel-pins-asme-b18-8-2-inch

Schematic, not to scale.

Fits with

Dowel pins ISO 2338 and ISO 8734 (parallel pins, m6 and h8), 0.6–50 mm: diameter limits, chamfer c, commercial lengths20 sizes★ sheet
Dowel pins, 2–6 mm (ISO 2338 / DIN 6325), isometric render of a generated part
Dowel pins, 2–6 mm (ISO 2338 / DIN 6325)5 sizes★ 23 files
Spring pins: slotted (ISO 8752, ASME B18.8.2) and coiled (ISO 8750): diameter, wall, chamfer, hole size, shear + hole gauges, isometric render of a generated part
Spring pins: slotted (ISO 8752, ASME B18.8.2) and coiled (ISO 8750): diameter, wall, chamfer, hole size, shear + hole gauges98.3×20.7×3.0 mm★ 2 files
Taper pins: ISO 2339 / DIN 1 (1:50) and ANSI / ASME No. 7/0 to No. 14 (1/4 in per foot): diameters, taper, lengths + example taper pin models, isometric render of a generated part
Taper pins: ISO 2339 / DIN 1 (1:50) and ANSI / ASME No. 7/0 to No. 14 (1/4 in per foot): diameters, taper, lengths + example taper pin models17.9×17.9×50.8 mm★ 24 files
Clevis pins ISO 2341 B, Ø3 to Ø8, isometric render of a generated part
Clevis pins ISO 2341 B, Ø3 to Ø87 sizes★ 7 files

Questions

What diameter is a 1/4 in standard dowel pin?

0.2503 in max and 0.2501 in min (6.358 / 6.353 mm computed) in the ASME B18.8.2 standard series; the oversize series is 0.2511 / 0.2509 in.

What is an oversize dowel pin for?

Replacement in a hole that has worn: the oversize series is 0.0008 in larger than the standard series (Engineers Edge's table).

What is the length tolerance of a hardened ground dowel pin?

±0.010 in (Engineers Edge footnote, Amesweb).