Aluminum Round Tubes used for camping tent poles are referred to by their OD (Outer Diameter) measurment.
Common sizes are 16mm, 19mm, 22mm and 25mm.
The fittings sizes are then referred to by the OD size of tube they fit – not the size of the fitting or the ID (Inner Diameter) of the tube they go into.
Many people measure the ID of a tube to order fittings for existing poles
or
measure the part of the fitting that goes into the tube – possibly to match a fitting they already have
and this is where the confusion comes in.
So here is all the spec’s to hopefully make your ordering easier. Ideal tool to measure tubes and fittings is a vernier.
The exact measurements of the tubes are as follow:
- 25mm – 25.4mm OD with 1.22mm wall thickness. So the ID is approx. 23mm. That means the OD of the fitting that goes into the tube is just under 23mm.
- 22mm – 22.22mm OD with 1.22mm wall thickness. So the ID is approx. 20mm. That means the OD of the fitting that goes into the tube is just under 20mm.
- 19mm – 19.08mm OD with 1.22mm wall thickness. So the ID is approx 17mm. That means the OD of the fitting that goes into the tube is just under 17mm.
- 16mm – 15.88mm OD with 1.22mm wall thickness. So the ID is approx 14mm. That means the OD of the fitting that goes into the tube is just under 14mm.
So in summary. If you have existing poles you want fittings for, always refer to the OD of the tube that the fitting is for.
If you have an existing fitting, measure the OD of the fitting but then add the wall thickness of the tubing (2 x 1.22mm = 2.44mm) – as the wall thickness is on both sides of a fitting when measured.
NOTE: Most of these common tube sizes are also available in a 1.6mm wall thickness from some suppliers however If a tube has a wall thickness greater than 1.22mm – our fittings will not fit.
Finally, we have a massive range of fittings for 22 and 25mm poles, but for 16 and 19mm we pretty much only have rubber feet and plastic tent pole spigots. These smaller diameter poles are common used for holding window flaps up or as uprights for wind-breakers. For all other applications and especially telescopic poles, you will need to be using the 22 and 25mm tubing.