Measuring Chillum Length
Weed Wissen
It's frustrating when your new chillum arrives and turns out not to fit your bong because you got sloppy with the length and/or the joint size. Here's how and where to measure your bong's joint and chillum correctly:
Measuring the length of the chillum
For cutting a glass chillum to the right size, only one single measurement matters. And it's not the overall length, nor the length of the downpipe below the joint (the usually slightly milky, thicker piece of glass on the chillum where it later seats in the bong), but the length from the bottom end of the chillum up to the top edge of that joint. The reason is simple: only this measurement actually tells you anything useful. The overall length is irrelevant here, because there are complete inserts including the bowl as well as simple downpipes meant to be combined with separate bowls. Their overall lengths can differ dramatically. The only thing that truly matters is the length that disappears into the bong once the piece is inserted.
How do I find out the length?
Back in the day, long before smartphones, computers and fancy software were everywhere, people simply held a pen into the bong, measured the length with a ruler and, depending on the size of the bong, subtracted a couple of centimetres to give the chillum a little ground clearance. In the 21st century, the best approach is exactly the same, because a bong still is, and always will be, a fully analogue smoking device.
Determining the joint size
The joint size of a bong is nothing other than the average thickness of the ground-glass joint mentioned above, measured in millimetres. On the chillum this corresponds to the outer diameter (and on the bong's joint socket to the inner diameter), and it usually matches one of the following values:
- 12.5 mm
- 14.5 mm
- 18.8 mm
- 29.2 mm
Problems when measuring the joint thickness
Because a typical ground-glass joint is slightly conical, your own measurement can come out a little off. If you don't measure exactly in the middle of the joint, small inaccuracies can already creep in. Even so, you'll at least get a value that lets you draw conclusions about the size you're dealing with.
