Mast diameters

Question
Hi
Having some experience from kite-buggying my son and I are planning building landsailors based on windsurfer sails.  
The question is:  What is the internal and outside diameter of a windsurfing SDM mast? Is the SDM measure of 48 mm measured internally or outside?  If it is the internal diameter (to fit in mast-base and mast-extentions), is there then any standard for the outside diameter (to fit the boom bracket)?
We hope you can enlighten the subject. Thank you in advance.
Lars


Answer
It depends on where you are measuring.  At the base of the mast the internal diameter is consistent across most mast makers since the mast extensions must fit inside.  The outside diameter at the boom mount position is also consistent due to the need for different booms to be able to mount to the mast.  The rest of the mast is pretty much proprietary to each mast manufacturer.   I would not build anything based on written specs.  You should obtain a mast that you want to use and build to it.  The 48mm measurment sounds the diameter at the tip of the mast but tip diameter is not consistent across all mast manufacturers.