Need a big hex nut nobody stocks, a heavy structural nut, or a copy of an obsolete oversized machine nut? Send the mating bolt or the old nut for a quote in 12 hours — we machine it to the exact thread and grade.
When the Nut Is Too Big for the Shelf
Standard hex nuts thin out fast above M36. Past that, distributors carry a narrow range of sizes and grades, lead times stretch, and anything with a special pitch, a left-hand thread, or an obsolete OEM form simply isn't stocked. On heavy equipment, presses, moulds, wind and structural work, the nut is often the one part holding everything together — and the one part you can't buy.
EKINSUN machines it. We make large and oversize custom nuts — heavy and high hex, flanged, round and tube nuts — cut from solid and threaded to your exact bolt or shaft, in the strength class the joint needs, from your old nut or the mating thread. No CAD file or part number required, one piece or a batch, quoted within 12 hours.
Nuts We Machine
Heavy hex nut
DIN 6330 / ASME B18.2.2 — wider and taller than standard for high load.
Large hex nut
DIN 934 style, M30–M160 and imperial, full or thin (jam) height.
Structural HV nut
DIN 6915 / EN 14399 for pre-loaded structural steel connections — we machine custom structural nuts to both.
Special / left-hand pitch
Extra-fine, non-standard or LH thread single-pointed to your bolt.
Flanged large nut
Integral washer face to spread load and resist loosening.
Round & tube nut
Cylindrical nuts with spanner holes, slots or flats for tight clearances.
Custom structural nuts — HV (EN 14399-4 / DIN 6915) and ASTM A563 forms
Structural nuts are wider across the flats and taller than DIN 934 nuts of the same thread, so a standard nut cannot stand in for one. Custom structural nuts are machined to the HV dimensions below, or to ASTM A563 heavy hex dimensions for inch bolts, in the sizes, pitches and materials the structural ranges stop at.
| Thread | Across flats s (mm) | Height m (mm) | Matching bolt |
|---|---|---|---|
| M20 | 32 | 16 | HV bolt EN 14399-4, class 10.9 |
| M24 | 41 | 20 | HV bolt EN 14399-4, class 10.9 |
| M27 | 46 | 22 | HV bolt EN 14399-4, class 10.9 |
| M30 | 50 | 24 | HV bolt EN 14399-4, class 10.9 |
| M36 | 60 | 29 | HV bolt EN 14399-4, class 10.9 |
HV nut dimensions per EN 14399-4 (DIN 6915), nut class 10. Where the catalogue stops: HV form above M36, a left-hand or non-standard pitch, or a stainless or alloy grade the structural ranges do not list — machined from one piece.
Standards & Forms We Machine
| Standard | Form | Typical use |
|---|---|---|
| DIN 934 | Standard hex nut | General large-diameter fastening |
| DIN 6330 / 6331 | High & flanged hex nut | More thread engagement, higher load |
| DIN 6915 / EN 14399 | Structural heavy hex (HV) | Pre-loaded structural steel joints |
| ASME B18.2.2 | Heavy hex (imperial) | US structural & heavy equipment |
| Non-standard / OEM | Round, tube, special | Obsolete machine nuts, no published spec |
Large Metric Hex Nut Reference (DIN 934 width across flats)
| Thread | A/F | Thread | A/F |
|---|---|---|---|
| M30 | 46 mm | M48 | 75 mm |
| M33 | 50 mm | M52 | 80 mm |
| M36 | 55 mm | M56 | 85 mm |
| M42 | 65 mm | M60 | 90 mm |
| M45 | 70 mm | M64 | 95 mm |
Above M64, or in a special pitch, left-hand thread or heavy-hex width — that's exactly what we machine. The table above is only where the standard shelf tends to stop.
Where the Large-Nut Catalogue Stops
Most large nuts that cannot be bought are not exotic. One dimension has simply dropped off the standard table — the pitch, the across-flats or the height — and the distributor has nothing to sell. The rows below are the ones buyers send us; the full M56–M160 dimensions, weights and bar sizes sit on the large hex nut dimension table.
| What you need | In the catalogue? | What we machine |
|---|---|---|
| DIN 934 / ISO 4032 hex nut, M30–M64, class 8, plain or zinc | Yes — stocked | Buy it from stock. On a standard nut in a standard class no one-off can match that price, and we will say so in the quote. |
| Standard HV set M12–M36 (EN 14399) for a certified preloaded joint | Yes — stocked as certified bolt-nut-washer sets | Buy the set. A machined nut is not an EN 14399 assembly. Where the joint needs a size or thread the HV range does not cover, we machine the nut to the same dimensions and grade, with our material certificate rather than a set certificate. |
| M56–M160 coarse pitch, DIN 934 across flats | Stocked in carbon steel; thin and slow in stainless | Turned from bar to the DIN across flats and height, in the material the stockist does not carry. M56 and up → |
| A pitch outside the DIN 934 fine series — M120×3, or a left-hand fine pitch | No — the series gives each size one or two fine pitches; M90×2 and M100×2 are stocked, M120×3 is not | Single-pointed on the lathe to the pitch the rod already carries. Nut and bolt as a pair if you need both. Fine pitch above M64 → · M120×3 case → |
| Non-standard across-flats — 180 mm on an M120, wider than the DIN 934 hex of 170 | No — the standard fixes the hex | Hex milled to the width your spanner or pocket needs; bar stock chosen for the larger flats, not the standard ones. |
| A nut height that is not the standard m — taller for engagement in a soft casting, or a thin lock nut above M64 | No — DIN 934 fixes m at 0.8 d above M100 | Turned to the height the engagement needs, full-strength material, one piece up. Tall & thin nuts → |
| A194 2H properties on a metric thread — M30, M36, M30×1.5 | No — the standards do not cross | A 2H-grade body carrying the metric thread your studs use. Heavy hex nuts → |
| A worn or seized nut from an old machine, no drawing | No | Send the bolt or the old nut. We gauge the thread and machine the mate; the worn flanks are not the reference, the bolt is. |
Before you buy the stock nut, measure the pitch. Lay a rule across ten crests of the bolt or shaft: 55 mm is the M56 coarse pitch, 60 mm is the 6 mm standard from M72 up, and 40 or 30 mm is a fine pitch the shelf may or may not carry for that size. The diameter is on the label; the pitch is what sends nuts back. If the pitch you measured is one the catalogue stocks, buy the stock nut. If it is not — M120×3, M100×3, anything left-hand — send us the diameter, the pitch and the across-flats you need. How to measure it, and what each reading means →
Materials & Strength
| Material | Best for | Notes |
|---|---|---|
| Class 8 / 10 / 12 steel | Structural & high-load joints | Heat-treated, matched to the bolt grade; plated or blackened |
| Alloy steel (42CrMo4) | Highest load, fatigue service | Through-hardened for the biggest diameters |
| 304 stainless (A2) | Corrosive, washdown, outdoor | General corrosion resistance |
| 316 stainless (A4) | Marine & chemical | Chloride resistance for seawater and coastal plant |
| Brass / 6061 / 7075 aluminium | Non-galling, or lightweight large nuts | 7075 where a big nut must be light but still strong |
Match the nut grade to the bolt, or the threads strip. A large nut softer than its bolt fails by thread stripping before the bolt ever reaches its proof load — and on a big joint that fails quietly and dangerously. We machine large nuts to at least the bolt's strength class (8, 10 or 12), heat-treat to suit, and certify the grade so the joint is limited by the bolt, as it should be.
Class 10.9 nuts above M30 are machined from 42CrMo4 / 4140 / SCM440 / 42CrMo bar — one steel under four names; the 4140 / 42CrMo4 equivalents chart crosses them and gives the +QT strength by bar diameter.
How It Works
Send the bolt or the old nut
The mating bolt/stud, or the old nut — even worn or damaged. Tell us the strength class and pitch if you know them.
We measure and draw it
Thread, pitch, hand, width across flats and height measured and rebuilt — free, no part number needed. See how we work from a sample.
You approve, we machine
Cut from solid, thread single-pointed, heat-treated to grade, inspected before shipping.
Reorder anytime
We keep the thread and dimensions on file, so the next batch is a one-line email at a lower unit price.
Who Orders Large Nuts
"The nut on this press tie-bar is obsolete and no distributor carries the size"
Send the tie-bar thread or the old nut. We machine a matching large hex nut to the right pitch and grade, single pieces welcome — so the machine isn't idle waiting on a size nobody stocks.
"I need heavy hex HV nuts in a size or grade the merchant can't supply in time"
We machine structural heavy hex nuts to DIN 6915 / EN 14399 or ASME, in class 10/12, certified — so the connection is documented and the schedule holds.
"My design uses a big special-pitch thread and there's no catalogue nut for it"
We single-point the nut to your pitch — extra-fine, non-standard or left-hand on a large diameter — repeatable from saved data with material certs.
"I need a tall or flanged oversized nut for more engagement and it doesn't exist as stock"
We machine high nuts, flanged nuts and round tube nuts to your engagement and clearance — cut from solid, any diameter, one or many.
What Buyers Search For
Coupling nuts follow a different table, three diameters long at the DIN 934 flats; the coupling nut size chart covers M2 to M24 with across-flats, standard length and turns of thread.
Frequently Asked Questions
We routinely machine hex nuts well beyond the standard shelf range — M30 to M160 in metric and the imperial equivalents, and larger round or special nuts to order. Above the size where heavy hex stock disappears, a machined nut is often the only way to get one, and single pieces are welcome.
Yes. The nut must be at least as strong as the bolt or the threads strip. We machine large nuts in medium-carbon and alloy steels heat-treated to class 8, 10 or 12 proof loads, and mark or certify the grade. Tell us the bolt grade and we match or exceed it.
Yes — that is a common reason a large nut isn't available off the shelf. Extra-fine pitch, non-standard pitch, or left-hand thread on a big diameter are all single-pointed to match your bolt or shaft. Send the mating thread or the old nut and we reproduce it exactly.
Yes. Send the old nut — even a large, worn or damaged one — or the shaft it threads onto, and we measure the thread, pitch, width across flats and height and reproduce it. No part number or drawing needed; we work from the physical part.
Class 8/10/12 medium-carbon or alloy steel for structural and high-load nuts; 304 (A2) or 316 (A4) stainless for corrosive, marine or washdown service; brass where a softer nut protects the thread; and 6061-T6 or 7075-T6 aluminium where a large nut must be light. All cut from solid with EN 10204 3.1 certificates on request.
Yes — heavy hex (DIN 6330 / ASME B18.2.2), high nuts for more thread engagement, structural HV nuts (DIN 6915 / EN 14399), flanged nuts, and round or tube nuts with spanner holes or slots. Tell us the form or send the sample and we machine it to match — custom structural nuts in class 10 or 12 with non-standard widths across flats included.
Related Custom Fasteners
Large nuts pair with the parts they thread onto. We also machine large & oversize bolts (M20–M100), bearing lock & spindle nuts for the round-nut side, non-standard thread bolts and castle & slotted nuts. For anything one-off, see special fasteners made to drawing.
Large Nut Quote
Send the bolt or the old nut. Reply in 12h.
// Qty & price
1 pc
Sample price
Confirm fit before a run
10–50
Unit price drops
Setup cost shared
100+
Best price
All tiers quoted upfront
- →No distributor — you pay the maker directly
- →Thread & grade data saved — reorder anytime at lower unit price