FILENAMES: Four-Adjustment-Set-True.jpg Four-Adjustment-Set-True-4in.jpg DESCRIPTION: These are pictures showing how to modify a chuck for "set-true" adjustments. Posted by Peter Haas . The following description was provided: ================================================================= Four Adjustment Set-True Modification This is an adaptation of Eric R. Snow's set-true modification [ * ] , modified to provide four adjustments, rather than only three. This facilitates adjustments by providing two pairs of independent adjustments (distinct X- and Y-axes), rather than three dependent adjustments. File Four-Adjustment-Set-True.jpg is the JPEG for the generalized modification which is adaptable to most chucks which are larger than 4 inches in diameter.. The thick line on the body of the chuck represents the location of the adjusters. 10mm dog-point, brass insert setscrew adjusters are recommended. The adjusters are at 22.5, 112.5, 202.5 and 292.5 degrees. (I use 12mm studs for larger than 4 inch chucks). File Four-Adjustment-Set-True-4in.jpg is the JPEG for the modification which is recommended for 4 inch chucks. The arrow outside the body of the chuck represents the location of the adjusters. 8mm dog-point, brass insert setscrew adjusters are recommended. The adjusters are at about 19, 109, 199 and 289 degrees. (I use 10mm studs for 4 inch chucks). Interference is possible between the pinion retaining pin for the 0 degree pinion and the 19 degree adjuster. If interference is found, the pinion retaining pin can be turned down to clear the adjuster in the immediate area of the interference. In practice, the required reduction in diameter of the retaining pin has been very slight, and does not compromise the pin in any way. (There is a necessary tradeoff between interference with the pinion retaining pin for the 0 degree pinion and proximity to the bore of the 120 degree pinion, and this compromise seems to be a good one, short of relocating the pinion retaining pin for the 0 degree pinion to the opposite side of the pinion). Peter Haas. Supporting files: Four-Adjustment-Set-True.txt (this file) Four-Adjustment-Set-True.jpg Four-Adjustment-Set-True-4in.jpg [ * ] http://www.metalworking.com/DropBox/_2002_retired_files/Chuck1.txt