Diametrical magnetization is listed for ring and tube magnets on this site, alongside axial and radial. This guide explains what the term means in the context of a ring, how it differs from the other two listed directions, and what a buyer should write in an inquiry so the direction is not lost in paraphrase. The ring range itself — outer diameter 3.0–200 mm, inner diameter 1.5–150 mm, height 0.5–50 mm, standard tolerance ±0.05 mm and minimum ±0.01 mm — is published on the ring detail page, and this guide does not repeat it as a substitute for that page.
What diametrical means on a ring
A ring has an outer diameter, an inner diameter and a height, and its magnetization direction describes how the magnetic poles are arranged within that geometry. In a diametrically magnetized ring, the magnetization runs across the diameter: the poles sit on opposite sides of the ring when viewed across its diameter, rather than on its two flat faces. That arrangement is useful to picture before ordering, because a ring that looks identical from the outside can carry a completely different pole arrangement inside, and the outside appearance gives no clue which one it is. The direction term is therefore part of the product, not a note about it.
The practical consequence is that a ring inquiry without a direction is incomplete even if every dimension is correct. A supplier who receives outer diameter, inner diameter and height, but no direction, must ask which of the three listed directions — axial, diametrical or radial — is required, and the order cannot be confirmed until that question is answered. Writing the direction in the first message, copied exactly as listed, removes that round of questions. Where a drawing uses a different convention, add a plain-words description of the pole positions alongside the listed term so the two can be reconciled.
Diametrical is not radial
Diametrical and radial are the pair most often confused on rings, and the confusion is understandable because both involve the diameter. They are nevertheless different arrangements, and this site lists them as separate terms for that reason. A buyer who means diametrical but writes radial, or the reverse, has ordered a different magnet, even though the dimensions, grade series and every other line of the inquiry are identical. The safeguard is simple and mechanical: copy the listed term letter for letter, and do not substitute a synonym that feels equivalent. If the drawing's convention is unclear, describe the pole positions in plain words and let the review confirm which listed term matches.
The same caution applies to axial in segments on discs, and to through directions on blocks, but rings carry the sharpest version of the problem because they list both diametrical and radial side by side. A checklist that reads outer diameter, inner diameter, height, grade series and direction, with the direction checked against the ring list specifically, catches the error before it becomes an order. The magnetization directions guide on this site collects all six per-shape lists for exactly this kind of cross-check.
Geometry first: the ring's three figures
A ring inquiry needs three figures, and the inner diameter is the one most often omitted. Without an inner diameter, a ring inquiry is indistinguishable from a disc inquiry, and the two shapes have different tables, different tolerances in part, and different direction implications. State the outer diameter, the inner diameter and the height together, and check each against the ring range: outer 3.0–200 mm, inner 1.5–150 mm, height 0.5–50 mm. A value outside any one of those spans is a question to ask, not a figure to round into the range.
Height also deserves attention on rings, because a tall ring and a flat ring can share diameters and still be different parts. The height range for rings is 0.5–50 mm, and the inquiry should state the height the part actually needs rather than leaving it to a standard assumption. Tolerance should be stated as well, using the ring tolerances — standard ±0.05 mm, minimum ±0.01 mm — and naming which tolerance the drawing requires.
Temperature and fixing for a diametrical ring
Grade discussion for a ring follows the shared temperature table, not a ring-specific performance claim: N35–N52 at 80°C through 28EH–38EH at 200°C, with the M, H, SH and UH series between. State the temperature the ring will actually see, including heat from neighbouring parts, and discuss the series against that temperature. Fixing should be described too: whether the ring sits on a shaft, inside a housing, or against a plate changes which mating dimensions matter, and a mating dimension omitted from the inquiry will be asked for later. Coating is an open question on this site — please confirm coating requirements before ordering — because coating type names were not transcribed from the company's illustration.
Where a diametrical ring is one part of a larger assembly, name the assembly category if one applies, but do not assume an assembly parameter from its name. The assemblies page lists eight category names with no per-category figures, so an assembly requirement needs its own dimensions in the inquiry. That separation — ring specified as a ring, assembly specified as an assembly — keeps both specifications checkable.
Questions to send with a diametrical ring inquiry
A specification that can be answered names four items together: the shape family, dimensions inside that family's published range, the grade temperature series, and the magnetization direction exactly as listed for that shape. Add the operating temperature and the fixing method where they affect the choice, and ask coating and warranty as open questions. Please confirm minimum order quantity and lead time before ordering. Warranty terms are unavailable on the published pages — please confirm warranty terms before ordering. Certificates are available upon request; no certificate number or issuing body is published here.
An inquiry that names only a grade, or only a size, will be answered with questions rather than a confirmation, because neither item alone is a complete specification. The extra sentence that states the direction in plain words, or that gives the mating dimension for a fixing, is often the sentence that prevents a second round of correspondence, and it costs nothing to include at the start.
Frequently asked questions
Which grade series should I discuss for diametrically magnetized ring magnet?
Discuss the grade series against the shared grade maximum working temperature table, using the temperature the magnet will actually see in service, including heat from neighbouring parts. The series run from N35–N52 at 80°C through the M series at 100°C, the H series at 120°C, the SH series at 150°C and the UH series at 180°C to the EH series at 200°C. State the operating temperature as a figure in the inquiry, because a grade name without its temperature row has not been specified for a warm environment, and the review needs the temperature to confirm the series discussion rather than infer it from a name alone.
How exactly should I state the magnetization direction?
Copy the direction exactly as listed for the shape named in the inquiry, and do not substitute a synonym that feels equivalent, because the same word can describe a different arrangement on a different shape. Where a drawing uses a different convention, add a plain-words description of the pole positions alongside the listed term, so the review can reconcile the two without guessing. A direction that is assumed rather than confirmed is a common source of a magnet that is dimensionally correct and magnetically wrong for its fixing, so the extra sentence describing the poles is worth writing even in a short inquiry.
What should I ask about coating, warranty and certificates?
Please confirm coating requirements before ordering, because coating type names were not transcribed from the company illustration and no coating type is named on this site; state the operating environment with the coating question so the answer can be specific. Warranty terms are unavailable on the published pages, so please confirm warranty terms before ordering rather than assuming a term. Certificates are available upon request: name the certificate required and its purpose in the inquiry, because no certificate number, issuing body, scope or validity period is published here, and a named request can be matched to the order it belongs to.
What if my size or combination is not in the published range?
Ask whether it can be made, and send the dimension as written rather than rounding it into the published range. A value outside a shape range, a direction not listed for that shape, or a combination of features from two shapes should be raised as an explicit question, with a dimensioned sketch where the geometry is curved, holed or otherwise not captured by a single size figure. Please confirm minimum order quantity and lead time before ordering. A question asked before ordering costs one message; a forced fit into the nearest published table can cost the whole part, because a magnet that matches its order and fails its fixing is worse than an extra round of questions.