Fastener
Resources.
The know-how, in plain English. Guides that skip the jargon, reference charts you can actually read, and quick calculators — the same things our own staff lean on every day.
Not sure where to start?
You don’t need to know the lingo to get the right part. Pick the one that sounds like you:
Rather just ask a person? That’s what the counter is for.
Guides 5
Start here if a fastener is more or less a mystery. No experience assumed.
Counter questions, answered
The questions we field every day — sizing, grades, finishes, anchors, flanges — answered in plain English, the way we’d tell you in person.
Read the answers →How to measure a fastener
Diameter and thread the same for everything — then the right way to measure length for bolts, flat-heads, studs, and U-bolts. Printable ruler included.
Start measuring →Thread, grade & finish explained
Coarse vs. fine, Grade 5 vs. Grade 8, zinc vs. plain — what each one means and when it actually matters for your job.
Read the guide →Bolt, screw or stud?
The names get used loosely. Here’s the difference in one minute — so you ask for the right thing and we hand you the right thing.
Read the guide →Metric vs. inch
How to tell the two systems apart, the lookalike sizes that cross-thread (M8 vs. 5/16″), and how to read the head markings.
Read the guide →Choosing the right part 5
You know roughly what you need — here’s how to pick the right variant for the job.
Tapping screws: which type?
Thread-forming, thread-cutting, or self-drilling (TEK) — what “self-tapping” really means and how to pick so it doesn’t spin or split.
Read the guide →Choosing an anchor
Which anchor for concrete, brick, block, or drywall — wedge, sleeve, drop-in, concrete screw, toggle — matched to base material and load.
Read the guide →Washer types
Flat, fender, split lock, star, structural, Belleville — what each one does, when to use it, and the SAE vs. USS size difference.
Read the guide →Nut types
Hex, nylon-insert lock, jam, castle, flange, coupling, cap — what each is for, plus the nylock heat limit and when to double-nut.
Read the guide →Choosing a rivet
Blind (pop), structural, rivet nut, solid, drive and plastic — which rivet for the job, how to pick grip and drill size, and matching the material.
Read the guide →Reference charts 14
Look-up tables for when you know what you need. Printable, no sign-in.
Thread pitch & tap-drill chart
Threads per inch for every common inch size, coarse and fine, plus the right tap drill for a clean, strong thread.
Open the chart →Metric thread pitch & tap drill
Pitch and tap-drill sizes (mm) for M3–M24, coarse and fine — the metric companion to the inch thread chart.
Open the chart →Clearance holes
The hole to drill for a bolt to pass through — close, normal, and loose fit by size. The companion to the tap-drill chart.
Open the chart →Bolt grade markings & strength
Read the head markings at a glance — Grade 2, 5, 8, A325 and more — with proof, yield, and tensile strength side by side.
Open the chart →Drive & security screw ID
Match the recess to find your bit — slotted, Phillips, Pozidriv, square, Torx, hex — plus the common tamper-resistant security drives.
Open the chart →Bolt & screw head styles
“What kind of bolt is this?” — match the head profile: hex, carriage, socket, button, flat, oval, and more.
Open the chart →Wrench & socket size
What size wrench fits which bolt — across the head, by diameter, for both hex and heavy-hex.
Open the chart →Decimal · fraction · metric
The conversions you reach for constantly — fractions to decimals to millimeters, in one tidy table with a live converter.
Open the chart →Lag screw pilot holes
Drill the right pilot for a lag screw — by diameter and by wood type — so it bites without splitting.
Open the chart →Screw extractor size guide
Broke a bolt off? Match the right extractor to the diameter, and the pilot hole to drill — plus how to back it out clean.
Open the chart →Flange stud & nut chart
How many studs and nuts per flanged joint — by size and pressure class (ASME B16.5), with stud diameter and length.
Open the chart →U-bolt & pad fit chart
Insulated pipe U-bolts and the pads they seat on — sizes for both, and the one measurement that has to match.
Open the chart →Hex cap screw dimensions
Across flats and corners, head height, thread length and stress area for inch hex cap screws (ASME B18.2.1).
Open the chart →Heavy hex bolt dimensions
Structural A325 / A490 (ASME B18.2.6) and heavy hex bolts (B18.2.1): across flats, head height, thread length and the wrench.
Open the chart →Machine screw head dimensions
Head size, Phillips driver and wrench size for flat, oval, pan, round, truss, fillister, binding and hex head machine screws (ASME B18.6.3).
Open the chart →Metric socket head cap screw dimensions
Hex key size, head height and thread length for DIN 912 / ISO 4762 socket head cap screws, M2 to M48, plus DIN 7984 and DIN 6912 low heads.
Open the chart →Metric set screw dimensions
Hex key size, key depth and point sizes for DIN 913 / 914 / 915 / 916 set screws — flat, cone, dog and cup point, M1.6 to M24.
Open the chart →Metric flat & button head dimensions
Hex key size, head diameter and head height for DIN 7991 flat head and ISO 7380 button head socket cap screws.
Open the chart →Metric machine screw dimensions
Head diameter, head height and Phillips size for DIN 7985 pan, DIN 963 / 965 flat and DIN 966 oval head machine screws.
Open the chart →Metric nut dimensions
Wrench size and height for DIN 934 hex, DIN 985 nylon-insert, DIN 439 jam, DIN 980 all-metal, DIN 6923 flange and DIN 937 castle nuts.
Open the chart →Metric washer dimensions
Hole, outside diameter and thickness for DIN 125 flat, DIN 9021 large and DIN 7980 high-collar lock washers.
Open the chart →Pin dimensions
Cotter pin head and prong, clevis pin head and cross hole, and slotted spring pin drill sizes and shear (ASME B18.8.1 / B18.8.2).
Open the chart →Hex key sizes
Across flats and arm lengths for inch (ASME B18.3) and metric (ISO 2936) hex keys, and which key fits which socket screw.
Open the chart →Hex flange bolt dimensions
Wrench size, flange diameter, head height and thread length for serrated and smooth hex flange bolts (IFI-111).
Open the chart →Tapping screw dimensions
Threads per inch, head sizes and driver sizes for Type A, AB and B sheet metal screws and self-drilling (Tek) screws.
Open the chart →Plow bolt dimensions
Head diameter, square neck and thread length for No. 3 and No. 7 head plow bolts (ASME B18.9).
Open the chart →Wood screw dimensions
Threads per inch, thread diameter and head sizes for flat, oval and round head wood screws (ASME B18.6.1).
Open the chart →Drill bit sizes
Decimal sizes of number, letter, fractional and metric drills, jobber and screw machine lengths, and the tap drill for each thread (ASME B94.11M).
Open the chart →O-ring sizes
AS568 dash numbers with the actual inside diameter and cross-section, tolerances in inches and mm, and the 900 series boss gaskets.
Open the chart →Pipe thread sizes (NPT)
Threads per inch, pipe OD, hand-tight and effective thread length, wall thickness and the tap drill for each pipe size, 1/8 to 6 (ASME B1.20.1).
Open the chart →Eye bolt dimensions
Shoulder, plain, turned and lag eye bolts: what each is for, which can be used for lifting, and forged shoulder eye bolt shank and eye sizes.
Open the chart →Socket and wrench sizes
Which socket or wrench fits which bolt and nut, inch and metric, drive sizes and mm equivalents.
Open the chart →Retaining ring sizes
External, internal and E-ring sizes: free diameter, thickness, groove diameter and groove width.
Open the chart →All-metal lock nut dimensions
Wrench size and thickness for prevailing-torque, top lock, two-way reversible and K-lock (Kep) nuts.
Open the chart →Coupling nut dimensions
Wrench size by thread and length for hex coupling nuts, where the standard and makers agree.
Open the chart →Key stock sizes
Which key fits which shaft, and the keyseat depth, for square and rectangular keys (ASME B17.1).
Open the chart →Thread repair insert sizes
Helical coil insert lengths, STI tap and the tap drill for each thread, where Heli-Coil and Recoil agree.
Open the chart →Solid rivet dimensions
Head and shank sizes for button, flat, countersunk and truss head solid rivets (ASME B18.1.1), hole drills and aluminum alloy codes.
Open the chart →Concrete anchor sizes
The drill bit for wedge, sleeve, drop-in, concrete screw and lag shield anchors, and embedment where the makers agree. Loads come from the maker.
Open the chart →Shaft collar dimensions
Outside diameter, width and set screw for set screw, one-piece and two-piece clamp collars, where Climax and Ruland agree.
Open the chart →Clevis dimensions
Adjustable clevis yokes and structural clevises: thread, pin, slot and length, where makers agree.
Open the chart →Drywall screw dimensions
Coarse vs fine thread drywall screws (ASTM C1002 / C954), bugle head and Phillips bit size.
Open the chart →Thumb screw dimensions
Shoulder vs plain thumb screws, the threads they come in and the tap drill for each.
Open the chart →Wire terminal sizes
Ring terminal color code by wire gauge, stud sizes and insulation, where the makers agree.
Open the chart →Hollow-wall anchor sizes
Hole size for toggle bolts, mollies and plastic anchors in wallboard, plaster and hollow block, where the makers agree. Loads come from the maker.
Open the chart →Turnbuckle sizes
Turnbuckle end types, thread and take-up sizes, and how to use them. Ratings come from the maker.
Open the chart →Tube fitting sizes
Thread for each tube size on 45° flare, inverted flare and compression fittings, and the dash size, where the makers agree.
Open the chart →Masonry drill bits
ANSI B212.15 carbide tip sizes, SDS-plus and SDS-max shanks, and which anchor each bit drills for.
Open the chart →Reamer & countersink sizes
Chucking reamer lengths, taper pin reamers, center drills, and which countersink angle matches which screw.
Open the chart →Hydraulic fitting sizes
JIC 37° and O-ring boss threads by dash size, and the hydraulic pipe end, where the makers agree.
Open the chart →Push-to-connect fittings
How push-to-connect fittings are sized, connected and released, and the air brake standards.
Open the chart →Abrasive & saw blade guide
How to read a grinding wheel marking, wheel types, grit scales, paper weight and saw blade teeth per inch.
Open the chart →Wire connector sizes
Spade, quick disconnect, butt splice and lug sizes: color code by wire gauge, tab widths and stud sizes.
Open the chart →Machine bushing sizes
Narrow and wide rim machine bushings: outside diameter by shaft size and 10 / 14 / 18 gauge thickness.
Open the chart →Rivet nut sizes
Rivet nut grip range, hole and drill by thread for flat head, ribbed and half hex styles, where the makers agree.
Open the chart →Wing nut dimensions
Cold-forged and stamped wing nuts: wing spread, wing height and boss size, #4 to 3/4 inch.
Open the chart →Grease fitting sizes
Zerk and DIN 71412 grease fittings: thread, hex and height for straight, 45, 65 and 90 degree, button head and drive fittings.
Open the chart →Nylon-insert lock nut dimensions
Wrench size and thickness for nylon-insert (nylock) nuts, 1/4″ to 1-1/2″ — and where they take a smaller wrench (ASME B18.16.6).
Open the chart →Acorn nut dimensions
Wrench size, height and thread depth for low crown acorn (cap) nuts, #6 to 3/4″ (SAE J483).
Open the chart →Hex flange nut dimensions
Wrench size, flange diameter and thickness for serrated and smooth hex flange nuts, #10 to 3/4″ (ASME B18.2.2).
Open the chart →Square head bolt dimensions
Wrench size, across the corners, head height and thread length for square head bolts, 1/4″ to 1-1/2″ (ASME B18.2.1).
Open the chart →Carriage bolt dimensions
Head diameter and height, square neck size and minimum thread length for carriage bolts, #10 to 1″ (ASME B18.5).
Open the chart →Flat washer dimensions
Hole, outside diameter and thickness for SAE and USS flat washers (ASME B18.21.1) and F436 structural washers.
Open the chart →Lock washer dimensions
Hole, outside diameter, thickness and width for regular split lock washers, #2 to 1-1/2″ (ASME B18.21.1).
Open the chart →Hex nut dimensions
Across flats, corners and thickness for hex, heavy hex and jam nuts, with the wrench for each (ASME B18.2.2).
Open the chart →Metric hex cap screw dimensions
Wrench size, head height, thread length and stress area for metric hex cap screws M3–M36 (DIN 933 / 931).
Open the chart →Socket head cap screw dimensions
Hex key size, head diameter, head height and key depth for inch socket head cap screws, #0–2″ (ASME B18.3).
Open the chart →Socket set screw dimensions
Hex key size, key depth and point sizes for inch socket set screws — cup, flat, half-dog and cone points, #0–1-1/2″ (ASME B18.3).
Open the chart →Flat & button head socket dimensions
Hex key size, head diameter, head height and key depth for inch flat (countersunk) and button head socket cap screws (ASME B18.3).
Open the chart →Shoulder screw dimensions
Shoulder diameter, thread size, head size and hex key for inch socket shoulder screws (stripper bolts), 1/4–2″ (ASME B18.3).
Open the chart →Square head set screw dimensions
Wrench size, head height and point sizes for inch square head set screws, #10–1-1/2″ (ASME B18.6.2).
Open the chart →Socket pipe plug dimensions
Hex key, length, key depth and tap drill for hex socket pipe plugs — Dryseal (3/4″ taper) and flush (7/8″ taper), NPTF.
Open the chart →Nut & bolt grade compatibility
Which nut grade to use with which bolt — Grade 2/5/8, A325, A490, stainless — so the nut is at least as strong as the bolt.
Open the chart →Steel hardness conversion
Read across Brinell, Rockwell C, and Rockwell B — plus the approximate tensile strength — for non-austenitic steel.
Open the chart →Fastener specifications (ASTM & SAE)
Plain-English guides to the specs on your prints — SAE J429, ASTM A307, A325, A490, A193 B7, A194 2H, and F1554.
Browse the specs →Calculators 3
Quick answers for the shop and the field. Type in your numbers, get a result.
Bolt weight calculator
Estimate the weight of a bolt or a box of them by size, length and material — handy for figuring freight before you order.
Open the calculator →Torque estimator
A starting-point torque value by bolt size, grade and lube — with a plain note on why these are estimates, not gospel.
Open the calculator →Epoxy anchor estimator
How much epoxy to set studs, threaded rod, or rebar in concrete — by rod size, hole and depth — totaled into cartridges.
Open the calculator →Still stuck? Talk to us.
Give us a call, send a photo, or bring a sample by. Fifty years in, there’s a good chance we’ve answered exactly your question before — and we’d rather you walk out with the right part than the close-enough one.