So, the instructions said 'drill the frames No 41 for 3/32" soft iron rivets'.
So I did. By the way, I'm talking about the frames for my Fowler4f. I did this some months ago.
Today, having finally made all the axle block horns and fitted them to the frames, I decided to drill through and rivet them in place.
This is when I found out what I should have done first. I should have bought the rivets before drilling the holes in the frames.
My No 41 drill measures 0.0967" . The rivets measure 0.0937" Equals a sloppy fit.
No 42 comes in at 0.0925" , Much better. So that's what I used to drill the horns.
Lesson; don't take every thing that the 'old masters' (Don Young in this case) say as gospel. Buy and measure your rivets first.
Dave.