Chapter Seven - The Fork

IMPORTANT: when tightening down the set screw that prevents the cutter from slipping in the holder, DON'T OVERTORQUE IT! overtorquing the set screw could split the cutter - that's about $125! Flip the whole assembly of the fork crown with the crown cutter in place up-side-down and pour cutting oil into the teeth of the cutter so it seeps down into the space between the tool and the steering column. This can be seen in Figure 7-13. Then turn the whole assembly upright and clamp the crown in the vise. After the assembly is clamped in the vise, turn the tool clockwise again to cut away excess metal on the fork crown race seat. Keep turning the cutter till there is a nice shiny ring of metal around the base of the crown race seat. (Remember, NEVER turn crown cutters counterclockwise! This will dull the tool quickly.) I have drilled a slanted hole in the side of the toolholder to add oil during the cutting process. This is much easier than repeatedly turning the tool up-side-down to add oil. This can be seen in Figure 7-13 After finishing with the 27.1 mm side of the cutter, remove the tool, spring, and nut, flip the #38S cutter over in the holder, and do the whole operation again with the smaller side of the cutter. This is step two of cutting the crown race seat.

FIGURE 7-13: Loading the up-side-down crown cutter with oil - cutter shown is a Cobra

FIGURE 7-14: Using the Campagnolo #718 to cut the final crown race press fit

Step three is to repeat the process with the Campagnolo #718 tool. This time though, the process must be done quickly and dry - no cutting oil and don't turn the cutter more often than absolutely necessary. It has taken me years to figure out how to cut this dimension by hand and have a press fit when I'm finished. The problem appears to lie in the fact that the Campagnolo #718 is an improperly designed shell end mill. A shell end mill that is properly designed will not have teeth on the inner diameter of the cutter. It's these inside teeth that tend to take the dimension undersized each and every time the #718 tool is used to cut more than about .03 mm off the diameter of the crown race press fit diameter. Figure 7-14 shows the Campagnolo #718 being used. To check for a proper press fit, Campagnolo makes a go-no-go gauge to slide onto the crown race press fit. The gauge should slide on easily when put on in one direction and not slide on from the other direction. Figure 7-15 shows the go-no-go gauge being used.

FIGURE 7-15:Campagnolo go-no-go gauge being used on the crown race of a 1" steering column

FIGURE 7-16: Cutting the press fit on the lathe - note use of left hand cutting too

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