Which M30 Adapter Do You Need? Pairs, Stock and What We Machine
People looking for an M30 adapter have two parts on the bench that will not screw together. One is M30. What matters next is the thread on the other part, and whether a dealer already sells that pair. Where the table says buy, buy it off the shelf: a stocked adapter costs a fraction of a machined one.
| Pair | Where it comes up | On a shelf? | What we do |
|---|---|---|---|
| M30 to M24 | A shaft, tie rod or spindle in M30 meets an accessory in M24. Often coarse on one side and fine on the other, such as M30×3.5 to M24×2 | No | Machined from one piece. Made already from a hand sketch, male-female and double-male: see M30 to M24 thread adapter |
| M30 to M20 | A two-size step in one body, where stacking two reducers would be too long | No | Machined from one piece, male or female on either side |
| M30 to M18, M22 or M25 | Sensor ports, fixtures, second-choice sizes that catalogues skip | No | Machined from one piece |
| M33 to M30 | A lathe spindle in one thread and a chuck or faceplate in the other | Rarely | Machined to your spindle, with the register diameter you give us |
| M35 or M36 to M30 | Bearing shafts and tensioners (M35×1.5 is the KM7 shaft thread), large bolts | No | Made already: M35 to M30 and M36 to M30 |
| M30 male to M10 or M12 female | A small sensor, eye or stud on a large tapped hole | No | Made already: M30 male to M10 female, and a female-female M30×1.5 to M12 in 316 |
| M28×1.5 to M30×1.5, or M30×1.0 to M30×1.5 | Thermostatic radiator head on an older valve body | Yes, in adapter kits | Buy the kit when it fits. We machine one in brass when no kit fits or the height is wrong |
| M30×2 to G 3/4 or G 1/2 | Hydraulic port to DIN 3852 on a pipe thread | Yes, at hydraulic dealers | Buy it if the dealer has the pair with the right sealing form. Otherwise machined |
| M30×1.5 or M30×2 to NPT, 1 1/16-12 UN or 3/4-16 UNF | Metric equipment such as a lab circulator on US pipework, or a US machine in a metric circuit | Rarely | Machined in steel or 316L, male or female, with an O-ring seat or a 37° cone on the UN side |
| M30 left-hand, any pair | Old machines, rotating parts | No | Machined, left-hand on one side or both: see left-hand thread adapters |
Every pair comes male-female, double-male (a stud with two threads) or female-female (a sleeve), with a hex cut to your spanner size. An adapter that has to sit flush inside the M30 hole as an insert depends on the wall left between the two thread roots: M30×3.5 to M20 leaves 2.85 mm, M30×2 to M24 leaves 1.77 mm, and M30×3.5 to M24 only 0.85 mm, so M24 in a coarse M30 hole needs its female thread in a collar above the hole. For small sizes see thread reducer inserts.
Price, Lead Time and Who Can Order
A plain steel M30 to M24 adapter starts at about €80 or $80 for a single piece. Setup is paid once, so the unit price falls with quantity: about €22 each at 10 pieces, about €16 at 50, about €15 at 100. These are indicative prices. Stainless steel, other pitches, longer bodies and tight tolerances cost more, and the quote fixes the price before you pay.
Quotes come back within 12 hours with a dimensioned drawing for you to approve. One to 50 pieces take about 5 working days after approval. Express delivery by DHL, FedEx or UPS takes 5 to 7 working days to the US or Europe, shipped with duty and tax paid, so nothing is collected at your door.
We make parts for private buyers and for companies. One piece is a normal order, with no tooling charge and no CAD file needed.
M30 Is Not One Thread: Four Pitches in Use
Diameter says nothing about pitch. Two M30 parts that turn twice and then jam almost always have different pitches, and ×1.5 against ×2 is the usual mix-up. Check the pitch on both parts before ordering anything.
| Pitch | Ten threads | Caliper inside female thread | Where you meet it |
|---|---|---|---|
| M30×3.5, coarse, ISO 261 | 35 mm | 26.2 mm | Bolts, shafts, tie rods, spindles |
| M30×3 | 30 mm | 26.8 mm | Old machines, recut threads |
| M30×2 | 20 mm | 27.8 mm | Hydraulic ports and fittings to DIN 3852 for 22L and 20S tube, fine-thread bolts |
| M30×1.5 | 15 mm | 28.4 mm | Thermostatic radiator heads, KM6 shaft nuts, axle nuts, sensor ports |
| M30×1 | 10 mm | 28.9 mm | Some older radiator valve bodies, fine mechanics |
Measure Before You Order: Three Numbers
Outside diameter of the male thread comes first: 30.0 mm is M30, 28.0 is M28, 33 is M33, 24 is M24. Pitch comes second: lay a steel rule from the 1st thread crest to the 11th and divide by ten, or use a thread gauge. Length comes third: usable thread length on each side, and the overall length or height the adapter may take up.
On a radiator valve, height matters more than thread. A kit adapter corrects the thread and never the height. If the head no longer closes or opens fully after fitting a kit adapter, the pitch is right and the height is wrong, and a third kit will not fix it.
An M30 Pair Already Made: M30×3.5 to M24×2 From a Hand Sketch
A customer sent a hand sketch for an adapter from M30×3.5 to M24×2 with a 50 mm hex, a pair no dealer lists. We dimensioned it the same day and machined it as a male-female adapter and as a double-male stud. Any other M30 pair follows that route: two threads, one length, one drawing to approve before cutting. Read the case from the hand drawing.
Materials
| Material | Grade | Used for |
|---|---|---|
| Steel | Carbon steel zinc plated, 42CrMo4 | Shafts, tie rods, machine building under load |
| Stainless steel | 304 (1.4301), 316L (1.4404) | Fluids, outdoor, marine, food |
| Brass | CW614N (C360 type) | Heating adapters, warm water, valve bodies |
| Aluminium | 6061, 7075 | Light duty, test rigs, sensors, prototypes |
What to Send
- Outside diameter and pitch on each side, or ten threads in millimetres and a photo with a rule.
- Male or female on each side, and what each side screws into.
- Overall length or height.
- Fluid and pressure if the adapter seals, and the material if it is fixed.
- Quantity: one piece, or a batch for a machine series.
Related: large metric thread adapters, hydraulic adapters, fitting thread identification chart and large nuts from M30.
Frequently Asked Questions
M30 coarse is 3.5 mm. Fine pitches in use are 2 mm on hydraulic ports and fine-thread bolts, 1.5 mm on thermostatic radiator heads, shaft nuts and axle nuts, and 1 mm on some older valve bodies. Measure ten threads with a steel rule: 35 mm means ×3.5, 20 mm means ×2, 15 mm means ×1.5, 10 mm means ×1.
Rarely. M30×3.5 to M24×2 mixes a coarse and a fine pitch, and dealers do not list it. We have machined this pair from a customer's hand sketch as a male-female adapter and as a double-male stud, and we make it from one piece.
A plain steel M30 to M24 adapter starts at about €80 or $80 for a single piece. At 10 pieces it is about €22 each, at 50 about €16, at 100 about €15. These are indicative prices. Stainless steel, other pitches and longer bodies cost more, and the quote fixes the price before you pay.
Yes. We make parts for private buyers and companies alike, and one piece is a normal order. One to 50 pieces take about 5 working days after you approve the drawing, then 5 to 7 working days by express courier to the US or Europe, shipped with duty and tax paid.
Usually not. A kit adapter from M28×1.5 or M30×1.0 to M30×1.5 costs a few euros and is the right choice when it fits. A machined adapter makes sense when no kit fits your valve body, or when the thread fits but the head no longer opens or closes because the height is wrong.
Yes. We machine M30×1.5 and M30×2 to NPT, to G (BSPP) and to R (BSPT), male or female on either side, in steel, 304 or 316L stainless or brass. Tell us both threads, which side seals and how, and the length.
Sources
- ISO, ISO 261 ISO general purpose metric screw threads, general plan, for the M30 pitch series.
- ISO, ISO 724 ISO general purpose metric screw threads, basic dimensions, for the minor diameter formula.
- DIN, DIN 3852-1 Ports and stud ends with metric fine pitch thread, for M30×2 ports.
Wall figures are calculated from the basic thread dimensions. Where this page and your drawing differ, the drawing governs.
Get an M30 Adapter Quoted
State both threads with pitch, male or female, length and quantity. Reply within 12h.
or email [email protected]