The Tyco/Mantua locomotives are the easiest HO mechanisms to convert to Sn3. Their non-shouldered axles make pushing the drivers to the new gauge easy.
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The drivers need to be pushed inward .044 per side. Push them .060 cut the axles off and pull them back to the correct gauge. It is easier to cut the axles off when they are beyond the driver.
Push the wheels together using a vise and a 1/2" hex nut. Use a Magic Marker to add color and scribe a line at .060. Don't try using the NWSL Puller to push the axles.
Use the Sn3 NMRA gauge to check the new gauge. If one of the wheels is out of perpendiculer persuade it back gently with smooth jawed pliers.
Scribe a line along the frame .044 in from the edge. Using the original frame width calculate the one side width and start filing. Check the new width regularly with calipers.
Remove the flanges at the arrows on the frame and bottom plate before you narrow the frame. That makes it easier to hold in the vice, D-oh!!!. Use magic marker to make a medium to draw scribed lines. Narrow the frame almost to the slot for the cylinder block.
Working metal is much more satisfying than plastic or wood. It cuts cleanly and crisply.
Narrowing the frame is suprisingly quick, less than an hour.
Turn the gearset bearings around and narrow them. Put the mechanism back together. It should roll smoothly.
Relieve the motor mount to clear the back driver. Hook a power pack to the motor leads and test your new loco.
Mantua used an O-Ring for a traction tire and wasn't very effective. Fill the O-ring groove with epoxy and trim it down with a razor blade after the epoxy is fully hard.
Measure the Tichy axles and the Sn3 axles. Shorten the bolster to accommodate the shorter Sn3 axle. Add a pad of .040 styrene punched out with a hole punch. Assemble the trucks.
Cut a piece of PCB to match the tender template. I used Radioshack PCB and found that it was brittle. Fit the tender floor to the body.
Cut and bend a Kadee #5 centering spring and attach the spring to the truck bolster. Adjust the wipers for maximum pickup with minimum drag. Solder short wires to the wipers. I use flexible wire from Litchfield Station.
Using the "tender template" grind the copper clad from the bottom of the tender floor.
Glue the center sill template to the center sill and drill and tap the
holes.
Mount the trucks to the center sill and cut the truck screws flush with the center sill.
Glue the template to the top of the tender floor. Center punch the hole locations and drill .047 diameter pilot holes. Drill out the holes.
Mount the center sill and drill the holes thru the center sill.
Assemble the tender.
Drill 1/16" diameter holes thru the frame. There are two injection pin dimples for location. Thread the motor wires through.
Hardwire the locomotive to the tender. We will add sound and DCC later.
The tender template is setup for HO Accumate Proto:HO couplers. They are the best operating couplers available and are S scale MCB couplers. They look like real couplers without the "hinky" spring.
Rubber cement a 1/2" hex nut to the tender frame for weight
Notch the tender body for your coupler.
That finishes the "Let's get a Sn3 Locomotive Running" phase. The next article will concern detailing he locomotive.
Make a tender drawbar screw from thin wall tubing, washer and screw.
Solder the truck wires to the tender floor.
The pilot wheels have "pizza cutter" flanges. They hit the spikes on PBL Code 55 flextrack. I can live with that for the moment. Will replace them later.
Just notch out the pilot to clear the wheels.
