Inlet manifold vacuum pipe take off fitting.

[Geoff Kingston]

Clive
I will check if I have a UNC thread gauge or get my pal Brian to check it for me if I don't, all I can say at this stage is that the tread gauge we tried in it gave a perfect fit at 14G/7/16 BSW. We are assuming therefore that this is telling us what the thread size is though I notice Brian cross references gauge readings to his ruler and a table of measurements so I might be wrong.
Another engineer I spoke to when looking for fittings told me it would most likely be BSP but nothing we had would fit.
I doubt very much at that tine that Bristol Cars would have used UNC threads anywhere on the car and there is no apparent wear in either fitting or the head.
Taking up on Kevin's point If I have to ask Brian to make some fittings I will see if he can make a few extra's. I have a friend who has made a jig to reproduce the wood frame for the back windows of the 401/403's but so far has not had any orders so it is a bit of a thankless task sometimes trying to help fellow owners.
Geoff.