It's clutch time.
The first item to make is the Lever Plate. As it's name implies, this plate fits at the rear of the rotating clutch assembly and carries the six levers used to disengage the clutch. The Lever Plate was going to require a session on the lathe, followed by at least three milling set-ups, and will involve work on three different machines. Therefore, some forethought was required regarding how to hold the stock and accurately position it for the different machining operations.
I started with 100mm x 100mm x 8mm thick aluminium plate. I always prefer to use 6082 T6 (HE30) for it's machine ability and corrosion resistance. I could hold the square plate in a four-jaw for the lathe work. Then bolt the plate to a sacrificial jig plate by four accurately placed bolt holes drilled near the corners.
The Lever Plate centre hole and outside profile were machined on the big lathe using a four-jaw chuck. The transferred to the mill for further machine work.
The first mill opp was to machine the 12 stepped pockets for the pressure spring holder on the front face of the Lever Plate. The embryo plate was bolted to a sacrificial jig plate by the four corner screws. The work was centred using the big central hole.
The work was flipped over to enable machine work on the rear face of the Lever Plate. I used a 2R x 6 OD, corner radius, bull mill to cut away the six pockets. The bull mill creates nicely radiused corners for authenticity and added corner strength. The 12 spring pockets, machined in the previous set-up, are now exposed.
Next. a 4mm ball mill was used to form the space in which the six clutch operating levers will reside. Note the wider lands where the clutch operating lever hinge pins reside. The mounting holes were then drilled around the outside, before the part finished Lever Plate was parted off from the square stock using a 3mm end mill.
The part finished Lever Plate was then transferred to the rotary table on my 4 axis machine for the six hinge pin holes to be drilled. The embryo plate was held in the three jaw chuck by it's outer diameter. An extra long centre drill was needed to reach in and spot the six holes, which were drilled and reamed to final size before the plate was indexed to the next position. Somehow, I have no photos of this set-up.
Finally, the whole Lever Plate was given a good clean up with wet-n-dry and Scotchbrite to remove the machine marks.
Much more to follow, so stay tuned
Mike
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