Forgot to post this, I finished a while ago
A quick video of where I am thus far
A handy little tool made from tinplate.
Basically it is made of 2 parts, the bottom piece, the”L” Shape piece and the upper triangle piece..
The L piece has an accurate right angle on the inside edge, the upper triangle is riveted to the L ensuring the edge is exactly set at 45 degrees.
You then place the tool over a Dowell with both edges of the L against the Dowell and draw a line using the triangle part.rotate the Dowell and repeat..you now have the centre of the Dowell.