I altered the standard ormerod 2 extruder body so that it could be fitted with a pneumatic fitting to hold the bowden tube . The extruder is made to be tapped for a 6mm thread which I found to be a nice neat fitting. The fitting I found on Ebay quite cheaply Item Number 271290823788 I also beefed up the extruder on the inside of the curve between where the filament enters the extruder and leaves the pneumatic fitting , It always looked to me that the filament would soon wear through the extruder body on the standard partI printed it in PLA with a 50% infill to make it a strong part