Method and fixture for reaming piston pin bushings in connecting rods

A method of reaming the piston pin bushing of connecting rods utilizing a fixture comprising a base plate having an eccentric member rotatably secured on a support column at one end and a reamer guide bushing of suitable dimension at the other end;

• indexing means supported on the base member and including detent means coacting with means providing different predetermined fixed rotational positions for said rotatable eccentric member for setting and fixedly detaining the rotatable eccentric member in a selected one of a number of different predetermined fixed rotational positions whereby the fixture readily and with precision can be adjusted to accommodate different length connecting rods;
• and locking means including a locking plate and locking nut;
• said method comprising:
• placing one end of the fixture in a vise;
• rotating the eccentric member relative to the indexing means to accommodate a particular length connecting rod placing said detent means in means defining said one of a number of fixed rotational positions;
• fitting the crankshaft journal end of the connecting rod on the support column over the eccentric member;
• fitting an adapter sleeve bushing on said eccentric member (if required) to adapt the eccentric member to accommodate the diameter of the connecting rod crankshaft end journal;
• setting said adapter sleeve bushing, connecting rod, and eccentric member only finger tight into rough aligned position with a locking plate and nut to bring the center axis of the piston pin end bushing of the conecting rod roughly into alignment with the center axis of the reamer guide bushing;
• inserting a reaming tool through the piston pin end bushing to be reamed, through a conical centering guide bushing and into the reamer guide bushing;
• locking the said connecting rod rigidly in place on the eccentric member with the center axis of the piston pin end bushing in accurate axial alignment with the center axis of the reamer guide bushing by turning down the locking nut on the locking plate with a wrench;
• removing the reaming tool and the conical centering guide bushing;
• and
• thereafter reinserting the reaming tool and reaming out the piston pin end bushing of the connecting rod with high precision.