Final assembly starts with the humble task of installing the worm gear on the motor axle. The manual recommends to ream the worm gear until there is a press fit. Ream from both sides, alternatively a few turns at a time to minimise the effect of the taper in the reamer. Once the exact fit is achieved the worm is secured with two component 5 minute epoxy glue.
Now the height of the motor needs to be determined. The big advantage of the LoadHoaler+ gearbox is its articulated design. By moving the motor to the left it also moves a bit down with the Final Drive Carriage hinging between the axle and the vertical part of the gearbox. The height of the motor axle should be aimed at the centre line of the boiler. In case of the NS 5000 I calculated that to be 12.8 mm over the running board, indicated by the calliper.
My friend Blu-Tack is of invaluable help. Sigh, a modeller should have four hands....
Once in position the inside of the articulated Final Drive Carriage is tack soldered. Check and check again if the height of the gearbox lands your motor in the right place. This is your final opportunity to correct things.
Once you are really sure solder the opposite side of the gearbox first to avoid disturbing the tack solder joint and with that the whole achieved setup. Then flip it over and give the tacked side the final soldering (yellow arrows)
Avoid soldering the steel axle with it. Adding a bit of grease before inserting axle prevents that.
Clean the joints from flux and superfluous solder
The test assembly taught me to start with the idler and then work my way up to the worm gear.
Insert the axle from the side where the gear will come. Move the spacer and the gear in place as per the manual. Move the axle almost all the way and stop a mil short of inserting it into the opposite side ( see drawing below)
Add two tiny amounts of epoxy glue around
the rim of the axle that is still protruding from the hole where you inserted the axle (yellow surface);
the inside of the opposite hole (blue surface);
indicated by the yellow areas in the drawing.
Then carefully guide the axle into the opposite hole (red arrow) without overshooting (because the axle will then drop out on the insertion side).
Avoid the glue contaminating the gear. If you use as little glue as possible you should be fine. If you happen to contaminate the gear disassemble immediately and wipe off all glue thoroughly and start over again. Once you are happy with the result let the epoxy cure for at least 15 minutes.
A word on the glue used. Why epoxy and not cyano-acrylate "super"glue. The latter can be used for its capillary action. But that is exactly the problem here. If the CA creeps in, where will it go with al the tine parts so close by. I deemed it uncontrollable. I also prefer epoxy over CA for its durability. CA will go brittle over time.
Now one gear is done the other two are a doddle. Working accurately is paramount though.
Reduction gear number two is next. This one is easy as there are no spacers or washers to be added and you have plenty of room to move the gear aside over the axle.
Reduction gear number one follows. This one is a bit more fiddly because of the spacer tube.
Mounting the final drive gear only makes sense if you also mount the gearbox in the locomotive chassis. For testing purposes (read: my personal vanity) I assembled it with one of the locomotive's axles away from the chassis.
Definitive assembly of the final drive gear coincides with mounting the gearbox in the chassis. That is a bit of a fiddly job and I made this video to demonstrate how I worked. It is not difficult, it just requires peace of mind and careful working.
And then it looks like this. What a beauty it is!!
Of course I grabbed the opportunity to test the gearbox thoroughly. Now is the time to hunt down any trouble.
It ran like dream.
Then I disassembled the final drive gear again and mounted the gearbox in the chassis and reassembled the final drive. The motor was coupled to the gearbox. I reassembled all axles and the coupling rods and put the chassis to the test:
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