... . Although there's an inch to play with (12" wide timber- 11" wide chair), so really it's between 2 and 3". For solid cast iron 'A' chairs (which I've never seen, the blunt nose is 2.5" from centre line of the keyed jaw, and as the chair is 12" wide, there's only one place this can go on a 12" timber, so that places the blunt nose at 1 7/8" from the C/L of the A timber. 499_121151_350000000.png Luckily Templot allows me to adjust this (via real> V-crossing options> customize V-crossing> blunt nose...). posted: 12 May 2018 18:16 from: Martin Wynne Hi Richard, Interesting topic. As usual it's not easy to pin down. The general rule for REA designs is 3/4" blunt nose (BH)= 4" from centre of "A" timber, i.e. timber centre is 10" from F.P. for a 1:8 crossing. ...