Glass water pipes use three standard joint sizes: 10mm, 14mm and 18mm, measured as the outer diameter of the male fitting. Every joint is either male or female, and a male accessory only fits a female joint. 14mm is the most common size in retail glass by a wide margin.
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What are the standard glass joint sizes?
There are three standard joint sizes in modern glass: 10mm, 14mm and 18mm. The number is the outer diameter in millimetres of the male part of the ground-glass joint. These are the same tapered joints used in laboratory glassware, which is why the sizes are consistent across manufacturers.
14mm is the dominant size in retail water pipes and rigs. 10mm is used on smaller rigs and travel pieces where a compact joint suits the airflow. 18mm appears on larger water pipes and on older stock.
| Joint size | Outer diameter | Most common on | Retail share |
|---|---|---|---|
| 10 mm | 10 mm | Small dab rigs, travel pieces, nectar collectors | Low–moderate |
| 14 mm | 14 mm (14.5 mm nominal) | Most water pipes, most dab rigs | Dominant |
| 18 mm | 18 mm (18.8 mm nominal) | Larger water pipes, older stock | Moderate |
What is the difference between male and female joints?
A male joint is the narrower fitting that inserts into something; a female joint is the socket it inserts into. A male accessory requires a female joint on the pipe, and vice versa. Size and gender must both match — a 14mm male banger will not fit a 14mm male joint.
This is the single most common ordering mistake at the wholesale level. When stocking bowls, bangers and downstems, order both genders in 14mm before adding either gender in 10mm or 18mm.
How do I measure a joint size?
Measure the outer diameter of the male fitting at its widest point with calipers, or measure the inner diameter of a female joint at its opening. The result will be close to 10, 14 or 18 millimetres. Because the joints are tapered, measure at the widest point — measuring further down gives a misleadingly small number.
If calipers are not available, a 14mm joint is roughly the diameter of a standard pencil and an 18mm joint is noticeably wider than a dime.
What is a joint adapter?
A joint adapter is a short glass piece that converts one joint size or gender to another — for example, 14mm female to 18mm male. Adapters let a shop sell an accessory that does not natively match a customer’s pipe, and they are inexpensive, high-turn add-on SKUs.
The most useful adapters to stock are 14mm-to-18mm and gender reversers in 14mm, since those cover the majority of mismatches.
What angle are joints cut at?
Joints are cut at either 45 or 90 degrees. A 90-degree joint sits vertical and is standard on beaker and straight-tube water pipes; a 45-degree joint angles outward and is common on recyclers and many dab rigs. The angle affects which bangers sit level, so bangers are also sold in 45 and 90 degree versions.
Frequently asked questions
- What is the most common glass joint size?
- 14mm is the most common joint size in retail glass by a wide margin, used on the majority of water pipes and dab rigs. 10mm is typical on smaller rigs and nectar collectors, and 18mm appears on larger pipes.
- Will a 14mm male banger fit a 14mm joint?
- Only if that joint is female. Joint gender must be opposite to fit: a male accessory requires a female joint and a female accessory requires a male joint. Size and gender both have to match.
- Can I use a 14mm bowl on an 18mm bong?
- Not directly, but a 14mm-to-18mm joint adapter will connect them. Adapters are inexpensive and are among the most useful low-cost accessories for a shop to stock.
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