Yes Steve that is also an option. DB spares in the UK suggested moving the steering arm on the spline at the top of the stub xle. When I look closely at this and compare one side to the other the drivers side arm is beneath the rim but the passengers side is not. So by moving the arm around on the spline which is a simple thing to do and make it sit in the same position, under the rim this should solve the problem. Then all I need to ensure is that the steering rod from the pitman arm to the axle has enough adjustment to cope with the change. I did think of cutting the threads equally at each end but then I thought that if the parts supplied were correct I should not have to cut the drag link. The supplier nor the david brown tractor club forum in the UK can answer why the new ball joints are 20mm wider when screwed onto the the drag link.
Hi Bugly, 5/8" is too small in diameter to fit this thread as it measures 11/16" OD. I have been sent a message with a list of tie rod ends supplied by BareCo that suit many different tractors. The only 11/16" threads listed are for MF and Ford tractors but with different tapers for the ball joint into the steering arm but most oddly a 10mm each difference in the width f the joint. Going by that list I have Ford parts supplied to me and does then resolve the 20mm extra width with the new joints.
I will try and download the chart and post it here later.