EKINSUN is a custom parts manufacturer that turns insert nuts, barrel nuts and plate nuts to drawing: a longer body for a thick board, a fine or inch thread, a brass or 316L insert for a marine or visible fitting, a flange sized to hide a chipped hole. The size ranges are those a distributor stocked in 2026.
A typical request: oak bar tops 60 mm thick with M10 bolts from underneath, where the stock inserts are 20 mm long and strip out of the end grain.
Length against thickness, and grain against thread form: two things the standard insert does not know about your board.
Insert nut types and size ranges
| Type | Standard | Size range | Common materials | Notes |
|---|---|---|---|---|
| Screw-in threaded insert (E-nut), hex drive | DIN 7965 form | M6–M10 | yellow-zinc steel; 304; brass to order | coarse external thread cuts into a pilot hole; flanged or flush |
| Screw-in insert, slotted drive | maker series | M4–M8 | zinc steel; 304 | driven with a screwdriver; softer woods |
| Self-tapping thread insert (slotted, three-hole, 302-type) | maker series | M2–M18 | 304; brass | the metal-and-plastic cousin, see inserts for plastics |
| Pronged tee nut | DIN 1624 | M3–M10 | blue-white zinc steel; 304 M4–M10 | hammered in from the back; prongs resist rotation |
| Three-hole plate nut | maker series | M6–M12 | zinc steel | screwed to the back face with three wood screws |
| Barrel nut / cross dowel | maker series | M4–M6 | 304; zinc steel | sits across a hole in a rail; bolt enters at 90° |
| Hex-socket clamp-plate nut (sex bolt / binding post) | maker series | M3–M10; posts Ø4–Ø5 | 304; brass; zinc steel | a nut with its own head; joins two panels face to face |
| Binding (book) screw | maker series | Ø5 × 3–100 mm; M4–M5 | brass; nickel steel | the same idea with a long sleeve |
| Wood dowel plug | — | M5–M12 sizes | beech | for repairing a stripped insert hole before a new insert goes in |
Need insert nuts for wood in a size, thread or material no catalogue lists? EKINSUN is a custom parts manufacturer: we make insert nuts for wood to your drawing, sketch or sample, steel, 304 stainless steel or brass, from 1 piece, quoted in 12 hours and shipped duties paid. Standard sizes can often be supplied from stock; the more pieces, the lower the unit price. All custom fasteners
Which insert for which board
| Board | Use | Pilot hole | Why |
|---|---|---|---|
| Hardwood (oak, beech, maple), side grain | screw-in insert, hex drive | about the insert's core diameter; the external thread cuts the wood | the coarse thread bites cleanly in dense wood |
| Hardwood, end grain | longer screw-in insert, or a cross dowel | as above, deeper | end grain holds threads poorly; length or a cross dowel makes up for it |
| Softwood (pine, spruce) | screw-in insert with a flange, or a tee nut | slightly smaller than in hardwood | the flange stops the insert sinking; a tee nut spreads load on the back face |
| Plywood | tee nut, or screw-in insert | as for the wood species of the plies | plies hold a tee nut well; glue lines can chip with a screw-in |
| MDF and particleboard | tee nut or plate nut on the back; screw-in inserts only in the face, never the edge | smaller pilot; the material crumbles | edge threads in MDF strip; a plate nut on the back face is the durable answer |
| Thick top, bolt from below | long custom insert | deep pilot | the standard 20 mm insert holds a fraction of the thread a 45 mm one does |
| Visible face, brass hardware | brass screw-in insert or brass binding post | as for the wood | matches the fitting; does not stain the wood |
What to send for an insert that is not standard
- Thread and pitch of the bolt or screw that goes in (metric, UNC for US furniture bolts, or fine).
- Board material and thickness, and whether the insert goes into face, edge or end grain.
- Insert length wanted, or the depth of thread engagement the joint needs.
- Flanged or flush, and the drive: hex socket, slot, Torx.
- Material: zinc steel for hidden joints, 304 for damp rooms, 316L for marine joinery, brass for visible fittings.
- Quantity.
Read the pitch before you order the furniture bolt. Lay a steel rule along ten thread crests and divide by ten: 10 mm over ten pitches is a 1 mm pitch (M6 coarse), 12.5 mm is M8 coarse, 15 mm is M10 coarse, 17.5 mm is M12 coarse. A reading that is not a round number of millimetres is an inch thread, and a reading that is shorter than the coarse pitch for that diameter is a fine thread. If diameter, pitch and the size range in the table all agree, the part is a standard size: buy it off the shelf, or have it made to order from 1 piece. If any of the three falls outside the table, we make it to your reading. The full measuring routine, including the inch traps
Where the insert nut catalogue stops
| What you need | In the catalogue? | What we make |
|---|---|---|
| Screw-in insert M6–M10 or tee nut DIN 1624 M3–M10 in zinc steel | Yes | Buy it from stock, or have it made to order from 1 piece. No one-off competes with a formed furniture insert. Standard parts: ask us too, we may have them in stock. |
| Barrel nut or cross dowel M4–M6, plate nut M6–M12 | Yes | Standard sizes: buy them off the shelf, or have them made to order from 1 piece. Standard parts: ask us too, we may have them in stock. |
| An insert longer than standard for a thick top, or shorter for a thin panel | No | Turned from bar with the same external cutting thread, to your length; from 1 piece. |
| An insert in a thread the standard skips: M12, M5 fine, 1/4-20, 5/16-18, 3/8-16 | No | Tapped to your bolt; external thread cut for your wood. |
| A brass, 304 or 316L screw-in insert above the standard sizes | No | Turned in brass CW614N, 304 or 316L. |
| A flange wider than standard to cover a damaged hole, or a countersunk flange | No | Flange turned to your diameter and profile. |
| A barrel nut in a larger diameter or with a longer thread, or a cross dowel for a thick rail | No | Turned; thread length and hole position to your rail. |
| An insert in aluminium 6061 or 7075 | Partly | Turned on request for light furniture and instrument cases; aluminium threads in wood wear faster than brass or steel, and we say so. |
Materials
| Material | Designation | Where it fits here |
|---|---|---|
| Carbon steel, yellow or blue-white zinc | low-carbon | standard screw-in inserts, tee nuts, plate nuts |
| Stainless 304 | 1.4301 / A2 | standard tee nuts, barrel nuts and clamp-plate nuts; damp rooms |
| Stainless 316L | 1.4404 / A4 | turned to order for marine joinery and outdoor furniture |
| Free-machining stainless | 303 / 1.4305 | custom turned inserts |
| Brass | CW614N / C36000 | visible fittings, instrument cases, binding posts |
| Aluminium 6061 | AlMg1SiCu | light turned inserts for cases and displays |
| Aluminium 7075 | AlZn5.5MgCu | turned where a light insert must carry more load |
| Beech | — | dowel plugs for repairing an insert hole |
Related pages
- fastener types chart, all families with standard and size range
- heat-set and press-in inserts, the same idea in plastic housings
- clinch fasteners for sheet metal, the sheet-metal equivalent
- brass fasteners, brass screws, nuts and binding posts
- closed-end nuts, the visible nut on a furniture bolt
- Knurled nuts, hand-tightened furniture nuts
Frequently asked questions
A tee nut is hammered into a hole from the back of the board; its prongs bite the wood and stop it turning, and the flange spreads the load on the back face. A screw-in insert is driven into a pilot hole from the front with a hex key or screwdriver and cuts its own external thread in the wood. Tee nuts suit plywood and softwood with access to the back; screw-in inserts suit hardwood and blind installation.
About the core diameter of the insert's external thread in hardwood, slightly smaller in softwood and MDF; the maker's table gives it per size. Too small and the wood splits or the insert shears; too large and the thread has nothing to hold.
In the face, yes, with a smaller pilot; in the edge, no, because MDF crumbles around an edge thread. For edge joints in MDF a plate nut or a tee nut on the back face, or a cross dowel, is the durable choice.
Yes. Inserts for 40, 60 or 80 mm tops are turned from bar with the same external cutting thread and a deeper internal thread, in steel, 304, 316L or brass, from 1 piece.
EKINSUN is a custom parts manufacturer that turns screw-in inserts, barrel nuts, cross dowels, plate nuts and binding posts in steel, 304 / 316L stainless, brass and aluminium, in metric, UNC and fine threads, from 1 piece, with a quote within 12 hours.
No list price; the drivers are material, length, the external cutting thread, the flange and quantity. A batch of long steel inserts for one kitchen order is a short lathe job; a single brass insert with a decorative flange is priced as the turned and polished part it is. The quote names the drivers.
Send the bolt, the board and the length
Thread and pitch, board material and thickness, face / edge / end grain, insert length, flanged or flush, drive, material, quantity. From 1 piece, quote within 12 hours.