Three parts, in order
Most soldering tip part numbers are built the same way, even when the letters differ: a platform prefix, a geometry letter, and a size or variant suffix. Read left to right and the code tells you which iron the tip seats into, what the working face looks like, and how big it is.
That is the whole system. The complexity comes from the fact that each manufacturer assigns letters within its own platform, and the same letter does not describe the same shape across platforms. A buyer who assumes otherwise orders the wrong part, and the error is only discovered when the tip will not seat or will not fit between components.
The platform prefix sets the seat
The prefix is the part that must match exactly. It encodes the seat geometry: shank diameter, insertion depth, the position of the shoulder that stops the tip, and the internal contact that carries heat. On a 900M-pattern iron the tip slides over a separate heater; on a T12-pattern station the heater is inside the cartridge. Those two parts are not interchangeable at any price, and no adapter makes them so.
This is also the segment that carries the compatibility claim. A tip labelled for a platform is a replacement part sized to fit that platform — not a part made by the platform's owner. XANJO tips are independent replacements, and the naming convention describes fit, not origin.
When a prefix is ambiguous, the seat drawing settles it faster than the label. That is why published dimensions matter more than a cross-reference table: the table is someone's interpretation, the drawing is the part.
The geometry letter is not portable
The middle segment describes the working face: chisel, conical, bevel, knife, horseshoe, bent. The trouble is that each platform defines its own letter set, and the same letter can mean a different face on a different platform, or the same face at a different angle.
Two consequences follow, and both cost money when ignored:
- Letters do not transfer. A shape you know by letter on one platform may be a different shape on another. Compare the face angle and width, not the letter.
- Letters are not exhaustive. Most platforms have standard letters plus variants for bent, long, and special faces. The variant suffix is where most ordering errors happen.
The practical rule: choose by the joint, then find the letter that matches that geometry on the platform you are actually using. Selecting by letter first is how a line ends up with a drawer full of tips that are almost right.
Size digits and variants
The trailing segment is a number, usually the face width in millimetres, sometimes a length class or a variant code. It is the part of the code that most often gets truncated in a spreadsheet, which is why two tips that differ by 0.4 mm end up as one line item in a purchasing system.
Size matters more than most buyers expect. A 1.6 mm chisel and a 2.4 mm chisel are the same letter, the same platform and the same price in many catalogues — and they behave differently on a 1 mm pad and a ground plane. If your BOM lists geometry letters without widths, the line will substitute whatever is in stock, and the process will drift.
Where a code carries a variant rather than a plain width, the drawing is the only reliable source. Long-reach, bent and reduced-face variants exist precisely because the standard part does not reach the joint.
Why codes do not cross platforms
Cross-reference tables are useful and dangerous in equal measure. They are useful because a buyer switching suppliers needs a starting point. They are dangerous because they compress three dimensions — seat, shape, size — into one row, and any error in the seat column produces a part that cannot be used at all.
The safer sequence is:
- Identify the platform from the iron model and the existing tip, not from a catalogue photo.
- Measure the shank diameter and length of the tip being replaced.
- Match the geometry by face width and angle.
- Confirm against a drawing before ordering more than a sample quantity.
A sample order that fits beats a container that does not. This is the reason we publish A/B/C/D dimension drawings with quotations rather than a compatibility matrix alone.
There is one more failure mode worth naming: the platform itself changes. Iron makers revise seats, heater cartridges and even the depth of the bore that accepts a tip, without changing the model number on the front of the station. A code that was correct five years ago can be wrong today for the same iron. This is why a cross-reference list should always carry a date, and why a buyer replacing a tip after a long gap should measure one before ordering the same part number again.
From code to drawing
A code is a label; a drawing is a specification. For any tip where fit matters — long reach, tight pitch, a seat that has been changed by the iron maker — the drawing should carry the shank diameter, the overall length, the face width and angle, and the shoulder position.
XANJO publishes those fields for every geometry, with a batch dimension report that records what was actually produced rather than what was intended. That is the difference between a part number and a part.
| Segment | Tells you | Does not tell you |
|---|---|---|
| Platform prefix | Seat geometry, heater interface | Whether the iron's seat has been revised |
| Geometry letter | General face family | Exact angle, which varies by platform |
| Size digits | Face width or length class | Tolerance, plating thickness |
| Variant suffix | Bent, long, reduced face | Reach dimensions — check the drawing |
If a supplier cannot tell you what the third segment means in millimetres, that is the answer to a different question — whether they know the part well enough to make it consistently.
Common questions
Can I use a T12 cartridge in a 900M iron?
No. The two codes describe different seats: a 900M-pattern tip slides over a separate heater, while a T12 cartridge contains its own. They are not interchangeable and no adapter makes them so.
Does a larger number always mean a wider face?
Usually the number is the face width in millimetres, but some platforms use it for a length class or a variant. Where the suffix is a variant, the drawing is the only reliable source.
Why do two sellers list the same code at very different prices?
The code describes fit, not construction. Plating thickness, its uniformity and the nickel barrier decide how long the part lasts, and those are not in the part number.
