[David Dunlop]

A good day today, and another milestone event in the largely mechanical so far, overhaul of the Sender. All the detail pieces for the Frequency MC Dial Assembly went back on.

A pretty straightforward bit of work, with the usual exception of getting the tab on the spring portion of the Bracket and Spring Assemblies No. C1 to pop back into its locking hole in the front panel. It is doable, but never yet have I been able to accomplish it without the tab cutting into the paint on the panel a little bit.

As I have mentioned before, this job is one to do with the Sender on its back so things stay put. The first parts back on were the front Clamping Plate and the small brass shim dropped over the central post. The large set of holes in the Clamp line up with the large holes on the drive and the smaller holes with the smaller threaded ones on the drive.

When you drop the dial itself in place, just make sure the three small studs in the central portion of the dial are on the side of the central shaft with the ‘flat’ cut into it. You will see a corresponding set of three holes on the bottom side of the Handles No. 72, the three studs on the dial will lock into. The two holes directly opposite each other hold the small pivot pins for the Clamping Screw Springs.

I put the Handles No. 72 face down on the bench and slide the two springs as far back into their slots as they will go. When I see the little central ‘V’ in each spring slide past the pin hole, I drop the pins in place. The next step it to get the inverted Handles No. 72 up off the bench and turned right side up without the pivot pins falling out.

What I do is take hold of the two ends of one of the springs with the thumb and index finger of one hand, making sure the spring ends are at the midpoint of the thumb and fingertips. Then close your thumb and finger so that the tips of each jamb in between the ends of the spring and the sides of the Handle. What this does is pull the spring against the pivot pin, locking it in place. Keep that tension on the spring and lift the entire Handles straight up, keeping it level.

Once you have the Handles above the bench, take the thumb and index finger of your other hand and rotate your wrist counter clockwise, until your thumb is behind your index finger. In that position, grab the other spring ends in the same manner as the first one putting the same tension on that pivot pin. While holding the Handles with your inverted hand, reorient your other hand on its spring so the thumb is also to the rear and reapply the tension on that pivot pin.

With both pins under tension now, you can turn your hands and the Handles right side up, align the flat of the Handle socket with the flat of the central shaft and lower the Handles onto the shaft until it is resting on the Dial. The Dial will now keep the two pivot pins from falling out and you can let go of the two springs. One last small step.

While holding the Handles to prevent it from turning, grab the rim of the dial with your other hand and turn it back and forth until you feel the three studs on it drop into the holes on the bottom of the Handles. The two parts are now correctly aligned. You can insert the central washer and mounting screw in the Handles now but only run it in about half way. And don’t tighten the grub screw yet either.

The odds are very good that when you install the Bracket and Spring Assembly, the rim of the dial will not automatically drop into its slot in the Drive Shaft, so by leaving the two screws in the Handles No. 72 loose at this point, you will be able to slip a small piece of wood under the dial and lever it into its slot. I use half of an old wooden clothes peg for that. Once that is done, the two screws can then be run home.

Once the Handles No. 72 is in place, you can install the four Clamping Screws. Start with the two Blue Indicator ones first. They are the ones that go into the larger pair of holes you noticed earlier. They reach all the way to the rear clamping plate assembly. When you feel the first of these two Clamping Screws catch the threads of the rear clamping plate, insert the second Clamping Screw directly opposite the first one. If you apply too many turns on the first screw, it will pull the Clamping Plate up at an angle and you will not be able to engage the second Clamping Screw. Once they are both engaged, tighten them and then back them off two full turns. This prevents a Flick Frequency being established in error. Then insert the two Red Clamping Screws in the same manner.

That is pretty much all the tricky bits that come with reassembling a Tuning Dial Drive.

Now I just have to repeat this process two more times and the Sender mechanical work will be almost finished.

David

PS: The toothpick in the photos was holding the Lower Flick Arm in place so it could be easily retrieved when it came time to inset the small lug on the end of the Tuning Drive into it.