Geoff, Your idea of fitting an O ring is of course the best solution to the
problem, however, putting a groove in the head is not an easy job. There may
be two other alternative ways to do this which would be easier, first there
is enough clearance to roll two grooves in the aluminium tube to take some thin
section O rings. Second it would be possible to fit longer tubes and fit O
rings on the ends, then roll the ends of the tubes over to trap the O rings.
I have no idea why they should machine the ends of the tubes in situ when
the ides was to seal them against the head.
My be you can let me have your email address and will contact you direct,
_pegasushunter-at-aol.com_ (mailto
egasushunter@aol.com)
My regards,
Alan Blackwood
Bellerophon