Paxman separates complete one-piece horn mouthpieces, detachable cups and detachable rims. This reference records the maker’s published dimensions and keeps standard Paxman, Series 5 and collaborative systems distinct.
Sources checked: . Next scheduled review: . These are access dates, not manufacturer revision dates.
4B: a complete mouthpiece, not just a cup
The checked one-piece 4B is product MP-PAX4B: a brass body with silver plating and a Morse (American) shank. Its published internal diameter is 17.40 mm, rim width 4.40 mm and cup bore 4.50 mm; its cup depth is described as medium.
The same 4B designation also occurs on a detachable cup. A cup requires a compatible rim; it is not the same purchase or configuration as the complete one-piece mouthpiece. The checked page does not specify a numerical cup depth, cup volume, backbore dimensions or exact diameter-measuring position. These remain unknown here.
Original sources: Paxman: 4B one-piece mouthpiece
Standard Series 2, 3 and 4
For each numbered series, A means shallow, B medium and C deep. The maker lists complete one-piece models and detachable cups separately. These labels describe depth, not a numerical cup volume or a universal cross-brand shape.
| Series / listed models | Internal diameter | Standard rim width | Published bore |
|---|---|---|---|
| 2 · 2A / 2B / 2C | 16.00 mm | 4.00 mm | 4.50 mm |
| 3 · 3A / 3B / 3C | 16.89 mm | 4.20 mm | 4.50 mm |
| 4 · 4A / 4B / 4C | 17.40 mm | 4.40 mm | 4.50 mm |
Original sources: Paxman: mouthpieces, cups and rims
Detachable rim options
The main catalog lists silver-plated, gold-plated and acetal rims. X identifies a narrower rim in these listed families; it does not change their published internal diameter. Material options are not medical safety guarantees.
| Rim | Internal diameter | Rim width |
|---|---|---|
| 2 / 2X | 16.00 mm | 4.00 / 3.70 mm |
| 3 / 3X | 16.89 mm | 4.20 / 3.90 mm |
| 4 / 4X | 17.40 mm | 4.40 / 4.00 mm |
| 5 / 5X | 17.50 mm | 4.50 / 3.75 mm |
| 5L / 5LX | 18.00 mm | 4.25 / 4.00 mm |
Original sources: Paxman: mouthpieces, cups and rims · Paxman: rim sizes and compatibility
Series 5 has its own cup descriptions
Do not transfer the standard A/B/C depth definitions automatically to Series 5. Here Paxman publishes both contour and bore, as shown below. A Series 5 cup still needs a selected rim.
| Cup | Published bore | Published contour |
|---|---|---|
| 5A | 4.50 mm | Medium bowl |
| 5B | 4.70 mm | Medium funnel |
| 5C | 4.70 mm | Deep funnel |
Original sources: Paxman: mouthpieces, cups and rims
Compatibility and unresolved details
Paxman describes Series 2, 3 and 4 rims as intended for their own model cup sets. Series 5 uses metric threads that the maker says can be compatible with PHC and Osmun; confirm the exact pairing with Paxman. The checked source does not give a numerical thread diameter or pitch, so this guide does not invent one.
A standard Paxman 4B is not a Denis Wick/Paxman collaborative model, nor a PHC configuration. A shared nominal diameter does not prove identical cup, rim, receiver fit or playing response. We use current maker dimensions rather than silently blending conflicting retailer figures. A source change alone does not prove a historical redesign.
Original sources: Paxman: rim sizes and compatibility · Paxman: 4B one-piece mouthpiece
Independent reference, not a performance promise
This is a selected source-checked reference, not an exhaustive stock list or a laboratory measurement database. Unknown specifications remain unknown. Manufacturer fitting advice, player reports and measured geometry are different kinds of evidence.
Commercial arrangements do not determine specifications. These are ordinary reference links; BrassFit has not activated a commission agreement with Paxman. Product prices are left to sellers’ websites.
Original source register
- Paxman: mouthpieces, cups and rims · accessed 2026-09-30
- Paxman: 4B one-piece mouthpiece · accessed 2026-09-30
- Paxman: rim sizes and compatibility · accessed 2026-09-30