Friday, October 16, 2009

Narrow Gauge - Part 4

The drivetrain - 
First you build the transmission.  This is mostly just a few gears and then a retainer that doesn't work so well - I started to worry a bit here as I was getting a little binding.  I fiddled with it and corrected it, but I didn't feel the gear retainer was seated properly.    After this you need to take the motor and install the worm gear, followed by the transmission, and then a brass contact bar.  The whole assembly is held together by a few more delrin parts, all just pressed on or fitted - no glue.   Oh, and most importantly, the motor has to be oriented a specific way otherwise you probably won't get electric contact. Also, oil the gears a bit.
One of the sideframes gets three gears - the motor only powers one axle, so this is the way of driving the other.   The gears sit in the frame and then you press the frame on and they are held in by that big flat piece I was wondering the purpose of.   Now the fun part - as I am modeling HOn30, and this is an HOn3 locomotive, you need to regauge the wheelsets.  I did this by taking off the outer axle gears - they fit on the rounded end of the axle if you loose track.   I then put the wheels in a vise and slowly pushed them together until we were at HOn30.  I had to compare the two and balance things out a bit, but it worked.  - Yeah.   Now you need to put the axle gears back on and then install the wheel sets - there is a front and a back - into the sideframe with the gears.  The gears need to mesh and then carefully install the opposite frame.  It's a bit tricky and make sure the gears don't bind.  
Now, the motor assembly.  First you will need to bend in the pick-up wires a little to fit the HOn30 wheelset.  Then the motor sort of just drops right in.   Careful that the brass wires from the early step make contact where they are supposed to.  Now you can throw it on some track and see if it runs or not.  At first mine sputtered and then sort of ran but didn't move a whole lot - one of the axle gears was slipping, on the non-driven axle.  I used a touch of ACC to bond this to the axle and then the locomotive started to move.  I could tell right away that weight would help this locomotive a lot.  There isn't a whole lot of room to put weight other than the cab - so I would have to sacrifice the interior cab details in light of having a better running locomotive.  

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