Been really flat out with work lately and haven't even had time to visit the forum much, let alone work on the car
I finally got my welder wired up, so managed to tack together my manifold.
Unfortunately, going up a size in pipes meant that I couldn't get nuts on half the studs anymore when I test fitted the manifold.
The nuts are brass M8x1.0, 13mm across the flats and only just clear a stock manifold - I've got a bunch of 13mm spanners I've ground down/cut/bent over the years to assist with the job.
I took some measurements and reckoned an 11mm ATF nut should fit... but could only find them in M8x1.25 of course so I'd have to make them myself - just for a change
I found a bit of 3/4" round brass bar I'd been keeping for a rainy day and turned it down to 12.6mm on the lathe then center drilled it to 7mm. 7.1mm would have been better for an 8mm thread, but close enough...
Then over to the mill where I took ~0.8mm off each face every 60* with a rotary table, then back to the lathe to tap the thread and part off.
I had to cut the threads by hand, I didn't like my chances trying to cut a very fine metric internal thread on a 70 year old worn out imperial lathe

- nut_tap1.jpg (63.35 KiB) Viewed 4925 times
Because the 13mm ATF nuts strip their threads often enough, I thought I'd make these ones slightly longer to have more threads engaged so I made a few in various lengths to see what fit best.
They still won't last forever, but shouldn't be any worse than the original nuts.
The 11mm ATF nut still only just clears the pipe:

- nut1a.jpg (59.81 KiB) Viewed 4925 times
So now I can get on with welding up the manifold, and suppose I can add "custom billet exhaust nuts" to the list of modifications
