I finally got the last of my NWSL parts in, so it's time to get started on my scratchbuilt freelance electric locomotive!
I thought it would be best to start from the bottom and work my way up, so the large central truck came first.
The first thing I did was assemble the long worm shaft, which is built into the truck. The pulley is made from two Intermountain 36" wheels. I decided to spend a little extra and get ball bearings rather than the usual sleeve type. I'm glad I did, because the tension from the belt would've caused a lot more friction in sleeve bearings.
The truck didn't come with anything but the axles and sideframes, so I had to make my own inner frame. I couldn't get enough power from my soldering iron to solder everything together, so I used super glue. I've rebuilt it twice since I took this picture to get everything lined up and working better. All is holding together well so far!
I decided to mount the motor with screws for better strength, as well as easier maintenance. The motor is a Maxon 9-pole coreless I bought a while back for a Hobbytown drive, but it didn't work as I'd hoped for that project. The pulley on the motor is made from 28" wheels, and I used a modern Athearn drive belt. I think Athearn is now using a material that won't dry out, so this should last a long time.
Quite an electrical system, isn't it? I kept adding wires and wipers to solve each electrical issue I came across. It looks messy, but it works well. Now let's see it running!
Smooth as silk! It's not silent because of my construction, but it's still pretty quiet! That belt drive is nice and strong, and isn't causing a single issue. I've since mounted a much larger weight. It's not big, but the whole assembly weighs close to a pound! Should be pretty powerful when it's all finished, because I'll be adding more weights to fill the body.
That's all for now. I'm still waiting on the rest of my parts, and some are important enough that I can't continue until I have them.
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Looking very good. Well done.
Chuck (Modeling Central Japan in September, 1964 - with catenary motors)
I'm just a dude with a bad back having a lot of fun with model trains, and finally building a layout!
I like the worm drive idea!
I've been thinking of scratch building a P5a but I couldn't come up with a logical drive mechanism - yours looks simple and reliable.
Did you build the worm axle yourself, or were the gears already assembled on there?
Keep up the good work!
Eric
I wish I was a headlight
On a northbound train
hon30critter, it will be DC. My layout's a bit too small and simple for DCC.
oo-OO-OO-oo, my mechanism is actually similar to the ones made by old brass manufacturers, except they usually use a gear transfer instead of a belt. The belt gets rid of the need to adjust gear mesh.
I did build the worm shaft myself. It's made from NWSL 2mm shaft and worms, ball bearings, and some brass tube to act as spacers. And of course, the pulley made of freight car wheels. It's actually pretty difficult to build one when all you have is a big vice, a Sharpie, and some extra tube...especially when it's so long...it's a wonder I didn't bend the thing...
If you're making your own mechanism for a P5a, you might want to consider using individual gearboxes to simplify gear mesh. NWSL's gearboxes are a bit expensive, but they work oh-so-smoooothly. The 28:1 gearing should work well for the P5a's 72" wheels. And you can still fit all of them to a single shaft.
Eager to see how your project develops! Keep us posted
That mechanism is one of the slickest things I've seen in a long time.
My hat is off to you-- that is really well thought-out. I'm eager to see what you do with it next!
-Fritz Milhaupt, Publications Editor, Pere Marquette Historical Society, Inc.http://www.pmhistsoc.org
Very nice. A lot of brass models actually used a spring belt - I guess the idea was a spring won't dry out like a rubber band will, but the few I've come across had issues where the spring looses tension over time and then the motor spins and nothign happens. The newer rubber should last a long time, and even if it does dry out years from now, it's easy to replace.
ABout the only thing I would have considered would have been an additional bearing just inboard of the pulley, although it doesn't appear you actually have room. This would keep the belt tension from lifting up on the worm for the end axle.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
I've seen those spring-belt drives before, usually in brass interurbans or other traction models. I've never seen one run though. Were they pretty quiet?
The Athearn belt is actually very flexible, so even when it's stretched pretty far, it's only snug (but has a very good grip!). The shaft is very strong, so I haven't had any problems with the belt lifting the worm.
I finally got the rest of my PSC parts, so work can continue! I'm still waiting for my Grandt Line windows, so body work will have to wait a little longer.
I've now built the frame extensions, added the front and rear trucks, reinforced the extensions for strength, added the rear pilot and coupler, and made additional weights. The chassis now weighs in at well over 2lb, and it's nice and sturdy. It was able to pull its first load (a dozen cars), and it barely noticed anything was there. The coupler overhang is about the same as an SD90, so it's just barely short enough to pull a 40' car around without derailments. My intention is for it to pull passenger cars, so the overhang will hardly be an issue. Next will be adding additional electrical pickup for more reliable operation.
Looking good Darth! It's shaping up to be an interesting beast. Looking forward to the body work.
Joe
Darth Santa Fe hon30critter, it will be DC. My layout's a bit too small and simple for DCC. oo-OO-OO-oo, my mechanism is actually similar to the ones made by old brass manufacturers, except they usually use a gear transfer instead of a belt. The belt gets rid of the need to adjust gear mesh. I did build the worm shaft myself. It's made from NWSL 2mm shaft and worms, ball bearings, and some brass tube to act as spacers. And of course, the pulley made of freight car wheels. It's actually pretty difficult to build one when all you have is a big vice, a Sharpie, and some extra tube...especially when it's so long...it's a wonder I didn't bend the thing... If you're making your own mechanism for a P5a, you might want to consider using individual gearboxes to simplify gear mesh. NWSL's gearboxes are a bit expensive, but they work oh-so-smoooothly. The 28:1 gearing should work well for the P5a's 72" wheels. And you can still fit all of them to a single shaft.
Thanks for the ideas!
That project is a ways away - but yours is definitely inspiring!