Sunday, July 29, 2012


Not visible in the flurry of scratchbuilding and kitbashing associated with the coke works branch, I have been working on trackwork, electrical, and scenery at the same time.  I'd like to get a fair amount of this branch up and running for the upcoming Steel Mill Modeler's Meet, of which, my layout will be on the tour.  (You can still register - information is on the Peachcreek site in my links section).

In building the landforms, of which my layout doesn't have too many - lots of little hills and embankments mostly and lots and lots of retaining walls, I've ended up with a gaping hole where the future ore dumper will be built.  No doubt, an elaborate scratchbuilt affair, as I outlined in Part 1 of this thread.  A sign indicating what was to be here, was my plan, until I came across one of the Walthers' Rotary Car Dumper kits at Sattlers on Friday night.  I thought why not, something is better than nothing, so I purchased it and after a brief meal, spent the remainder of the evening building the model.

It was an easy build and the fit of the parts were surprisingly good for a Walther's kit.  The instructions indicate that this model can be motorized but clearly state that other than leaving a drive shaft projecting from the base of the kit, the rest is on you.  I'd heard from others that despite this suggestion, in reality the kit can't be made to work.  This is common talk concerning some of Walthers' potentially working kits.  The Walthers' bascule bridge on our Free-mo module has been working fine with out of the box parts for years.  Almost every comment when we display this at Timmonium is, "nice bridge, shame it doesn't work" - Jimmy then promptly raises and lowers the bridge.  Admittedly, there are lots of plastic parts, including gears that could easily break on both kits, but I believe if you are careful with your alignments while building them you should be able to get them to work right for at least awhile.

A quick test with a cordless drill proved that everything was as it should be and if I could attach a motor to the shaft the model should work.   Before I could do this I needed to modify the rotary carriage a bit. First problem is that the kit is designed for modern wood chip hoppers, which are taller than the 1950s era hoppers that I am using to haul ore.  So I would have to modify the hold downs by quite a bit.  I wasn't able to move the hold down assemblies, and thought that 1/2" extension on the arms would look funny, so I raised the rail deck by 3/8" and added 1/8" I beams to lower the hold down arms a little.  This worked, but then I realized that I only needed the two center hold downs on both sides, not the four provided.  Because of the design of the kit it can be operated without a car - the bottoms of the hold downs will hit the cams in the base and not ride up on them like they should.  Only using four of eight hold downs presented the same problem as the four not engaged hit the cams.  I removed the four outer ones to eliminate this problem.  Raising the deck also necessitated raising the foundation walls using 3/8"x.080 strips.
Note raised deck, capped off hold down sleeves, and extended hold down arms

Motorization of this was a bit tricky.  My first attempt using sheaves and a rubber band belt didn't work.  My second attempt using junk gears and a motor out of an old printer did.  To make life easier, I screwed the base to a piece of 3/4" plywood, extending the wood on the shaft side to accommodate for the motor and gearing.

Not pretty, but it works


jeremy said...

you should add a fly-wheel to stabalize the jerky movement...however the jerkyness may aid in dumping the material.

Jim Musser said...

Hi Jeremy,

The jerkiness was me varying the voltage so I didn't over extend it. Doing that with one hand and holding the camera with the other. It's pretty smooth under constant voltage - once I have a proper switch...etc. I'll post another video


Jim Musser said...

Also, the gears on the dumper at molded styrene so a flywheel might add too much force