How to Measure a Ground Glass Joint Size

Users, especially those with less experience, can get overwhelmed by the data on ground glass joint sizes. When you search online, there’s an overwhelming amount of information that can be difficult to process. This is because there are so many types of glass, and when we get to the accessories, the list keeps getting longer.

The truth, however, is that finding the right glass joint size isn’t too complicated. All you need is a basic knowledge of glass, joint sizes, shapes, and their function. Part of what makes this task easier is the standardization of joint sizes by the industry.

Understanding Components

First and foremost, you need to know about the main elements of glass joints, namely the size and the ‘gender’ of the joint.

Gender

You need to determine the gender of your joint, i.e. whether it is male or female. The differences can easily be spotted. If your joint is ‘male’, then the accessories will slide on it, and if it is ‘female’, then the accessory will slide in it. Also note that if the joint is male, then the accessories will be female (and vice versa). So your female joint will have a male bowl inserted in it, or your male joint will have a female nail sitting over it. Simple as that!

Size

When it comes to glass joints, you have 3 sizes to choose from:

• 10mm (small-also known as a ‘nano’ joint)
• 14mm (medium)
• 18mm (large)

Note that there are some specialty joints that can be larger than 18mm, but these are the standard sizes that you get on the market. These standard sizes are suited for different types of pieces. If you use a pendant rigs, then you will go with the small size for concentrates. The medium and the large sizes are stronger and they are used on beakers or straight tubes.

Note that sometimes you see measurements like ’14.5mm’ or ‘18.8mm’, but you should not be confused. These are just technical terms and not actual differences in size. In other words, the 14.5 mm and 14mm refer to the same size. 14.5mm is technically correct, but it is labeled as 14mm for the sake of convenience. The same goes for 18.8mm joints. There are also sometimes labeled as 19mm because the marketer has rounded up the number to the nearest millimeter.

Taking Measurements

The simplest and most basic method of determining joint size is to measure your joint’s diameter with a ruler. Some people use every day hacks to measure their joint size. Note that 10mm is the smallest size, and hence is easily distinguishable. In order to distinguish between 14mm and 18mm joints, you can use a dime. The 14mm female joint is a just a little bit smaller than a dime, but you can easily drop a dime through an 18mm female joint.

So once you know your main components and how to determine the size, it will be easy for you to find the perfect accessories for your glass.