I recently had something of an unscheduled stop with my Juliet; I seem to have escaped almost unscathed, apart from my displacement lubricator that took a bit of a bash. I need to replace the adjuster shaft, which has clearly been made from a piece of studding.

Based on everything else being imperial, I took a rough od measurement and ordered the closest BA size to what my calipers suggested (7BA). Unfortunately this doesn’t fit. It’s rather fiddly to see exactly what I’m doing, but as far as I can tell the pitch is slightly coarser than 7BA, but the od slightly smaller. I’m a little sceptical of diameter measurements as the thread crests look a bit mashed. It’s definitely not 6BA as I’ve got some of those on hand to compare to.

Other components all seem to be BA or ME threads, but in desperation I did try m2.5, unc2 and unc4 which I had on hand without any luck.

Does anyone have any idea what this thread might be? I’d prefer to find the right studding than resorting to tapping up a size as most of my taps are metric.

Thanks,

Mike