This plan will build a Super Duty Flatbed that can handle two 6000# or 7000# axles. Included are steps for electric brakes, stake pockets, triple tongue & spare tire carrier.   Plan is adaptable for various widths & lengths.  Trailer pictured is an 8' X 20'.

Sample paragraph

Step 4.  Next cut 2 pieces of  6" channel each about 78" long and clamp to the "A"-Frame coupler for the tongue.  Set upside down on the trailer frame supported with another block. Adjust the tongue (forward or back) so the ends are just past the frame sides about ½" or so.  A general rule of thumb for axle placement is 1" back from mid-point for every foot of trailer length but to end up with 10-12% tongue weight, we will use 18" back from center. This will insure an appropriate amount of tongue weight.  For this 20' trailer, measure and mark a line on both sides 138" back from the front (mid-point of 120" plus 18" = 138").  This is where the middle spring hanger will go. Then measure and place a mark 30 1/2" in front & behind the first mark. This is where your other 2 spring hangers will go.