Real plans for a featherbed frame

Roy Bacon claimed the slimline steering head angle was 24 degrees, and the widelines, including the Manx, were 26 degrees. I've only had three featherbed frames, one Manx, one wideline (1959) and one slimline (Atlas). I measure them all (with lower frame rails level with the ground) and found both widelines to be at 26 degrees, and the slimline at 24. A limited sample, I admit, but it does seem to support Bacon's numbers.

Ken

Thanks Ken, makes sense.

Someone posted a drawing/blueprint of a slimline frame on the NOC forum.
Unfortunately it was only the lower half, but the whole thing could be had somehow.
Initially it was stated to be a wideline, but turned out to be slimline.
Not entirely sure the lower frame rail was horizontal. ?
Will see if I can find it, or stashed in my filing 'system'.