Create a clamp from openscad with or without a mounting plate. Main adjustments are shaft diameter, width, thickness, leg length, leg thickness, hole position(s) and diameter with or without mounting plate. Mount holes by default are 6 sided so it can be printed on it's side.

Adjust these parameters, output to stl and print on its side. All dimensions are in millimeters.

shaftDiameter = 25.4 ;
clampWidth = 20 ;
clampThickness = 2.6 ;
clampLegLengthFromShaft = 12 ;
clampLegThickness = clampThickness + 4.6 ; // default is 'clampThickness' to keep it the same thickness as the clamp
clampLegGap = 10 ;
clampToClampScrewCenter = (clampLegLengthFromShaft - clampThickness) / 2 - 3 ; //using '(clampLegLengthFromShaft - clampThickness) / 2' nearly centres this hole on the clamp leg
clampScrewDiameter = 3.5 ;
shaftToMountPlate = 0 ;
mountPlateThickness = 5 ;
mountPlateLength = 38 ;
mountHoleSpacing = 30 ;
mountHoleDiameter = 3.5 ;
screwHoleSmoothness = 6 ; //6 = printable vertically. Applies to mount plate screw holes and clamp leg screw holes
clampSmoothness = 60 ;

use

clampWithMountPlate();

or

clamp();