strange screw-thread on 1965 3000 (UK)

I have a 1966 UK-built 3000 with aftermarket power steering. I need to replace the 'track-rod ends' (see picture) as they are worn-out. I've managed to find replacements but they have a thread I can't find in any of the usual data tables. As far as I can tell the thread is definitely 16 TPI, probably 13/16" (it measures about 0.805" in it's worn state) and probably 60 degrees. The nearest thread data I can find is 3/4" UNF, but there doesn't seem to be a 13/16" UNF defined. Is it a one-off 'special' or just not a preferred size ? Also, could some kind soul please measure the diameter of this thread on a manual steering pre-force 3000 so I can see if it's the same ?
TIA

• power steering

Last set I needed, A & I had them for half the price as Ford - and had them listed for both Ford and IH tractors.

Can't tell you what the manual steering model has, but know the 8N tractors use some goofy thread size also, 11/16" diameter I believe. Don't know why they make them so odd. Would think even an aftermarket kit would used the same ends used on the stock power steering systems.

I've got a little further with this - the ones I found are originally for a Massey-Ferguson - perhaps the aftermarket kit was intended fit a number of different makes of tractor ?

I've also found out that there is a 'legitimate' 13/16" UNF whose specs appear to match this thread, so I'm assuming that's the one for which I need to find/make a thread-cleaning tap.

soundguy

Doesn't work when you've got a lathe...

soundguy