Never seemed weird to me.
I retired as a industrial machine mechanic in 2006 and I also bought the gear planning documents from NWSL back in 1976 which explained how to build gears sets.The documents are still online i belive
They aslo sell reverse worms and reverse worm gears. Interesting.
Rich
If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.
The gear on the motor is a worm (gear).
It engages a worm gear.
So. A worm engages a worm gear.
Weird. But true.
Ed
Quite a few years ago I re-geared some HO loco using the NWSL 45 to 1 and 72 to 1 MDC gear sets. I used the Sagami can motors set in bath caulk and carefully adjusted for minimum gear lash before the caulk set up. That took a little work. Those motors were quiet because of the bath caulk. Even the ones with 72 to 1 gears. I made sure nothing touched the motors in the loco shell. I ran them with a DC power pack using PWM and they could creep really nice.
NWSL sold Sagami at the time when they were in Washington State.
I built my own setup like MDC used. Worm on the motor, worm gear on idler shaft with a spur gear and a spur gear on the loco driver. Many call the gear on the motor a worm gear.
The NWSL tools really helped.
All my Athearn Roundhouse locos are like that.
LewPhelps Many thanks for the detailed feedback, Hornblower. I have figured a way to isolate the existing open frame motor (a strip of electrician's tape under it and a nylon 3-48 screw), which I will try, but may replace the motor even if that works, so that I can add a flywheel and lower gearing for better low speed performance. I'll keep you posted on the progress. Lew
Many thanks for the detailed feedback, Hornblower.
I have figured a way to isolate the existing open frame motor (a strip of electrician's tape under it and a nylon 3-48 screw), which I will try, but may replace the motor even if that works, so that I can add a flywheel and lower gearing for better low speed performance.
I'll keep you posted on the progress.
Lew
Simon
Just an FYI, the July issue of RMC has an article on up-dating a brass steam loco for DCC, and overall better electrical pick-up.
I'm not into brass, or metal locos, or steam, I seen the article as I thumbed through the issue while leaving the post office.
Maybe something that you might be interested in.
Mike.
My You Tube
1. Yes, correct installation of the NWSL 72:1 regear kit does require replacing the gear on the driver axle. Being a cheap screw, I didn't buy a wheel puller. Instead, I simply cut a slot in a piece of heavy sheet steel, slipped the axle into the slot, placed the sheet metal plate across the open jaws of my bench vise, then used a small pin punch to gently push the axle out of the wheel. The original gear can be removed the same way. The new NWSL gear slipped on with gentle pressure. Mark the wheel and axle prior to disassembly so you can maintain proper wheel quartering upon reassembly. I used a razor saw to cut a small notch in the end of the axle and wheel hub (not much more than a visible scratch will do).
2. It's been a while since I built these kits but I believe I used the NWSL 1630D-9 motor. With the 72:1 gearing, these motors are plenty strong enough to pull a train of 15 or more cars. Mine pull 10-car trains up my 2.62% helix without problems. The loco wheels will spin before the motor stalls! I see that NWSL still offers their MDC 72:1 regear kit for both the original open frame and later can motors. If you change to a can motor, you'll likely have to fabricate a new motor mount. The new mount will have to hold the new idler gear between the worm gear on the motor shaft and the drive gear on the wheel axle. If you fabricate the new motor mount using styrene, it will also isolate the new can motor from the frame. Since the kits I built all had the later can motor and matching motor mount, I simply isolated the motor from the original mount.
3. I would imagine a reaming tool small enough to drill through the cast metal boiler front would be just as fragile as a drill bit. You don't have to use a really tiny bit. Just frequently lubricate whatever bit you do use and don't force the cut! It will take some time but it will make it very easy to add a working headlight.
Keep us posted with your progress!
Hornblower
With the small DC motors we use, it's easier for the designer to use the same brush mount for each of the (usually two) brushes. Since one HAS to be insulated from the motor frame, that means that the simple solution is to insulate BOTH. Which is just what Pittman did for most of their motor line. When they decided to ground one brush to the motor frame of the DC-70, they had to add an extra piece to do it. Which can be removed.
I suppose that someone could have built a can motor where the ground connection is internal and nearly impossible to get to to remove. There's a very simple test: check with you VOM if there is continuity between the frame and either brush mount.
I've purchased engines with can motors that were connected to the frame and need to be isolated for DCC conversion. Open-frame motors and can motors both have to be isolated from the frame for DCC. Can motors started to be used in 'ready to run' engines about the time manufacturers started to isolate the motor from the frame to make DCC conversions easier, but it's just a coincidence of timing.
emdmike I highly recommend replacing the field magnet.
Brilliant idea! I couldn't find neodymium magnets anywhere on the Micromark web site, but they are availalable at low cost in a number of sizes and shapes from www.allelectronics.com. In fact, I already have some, which I had ordered for another purpose. Thanks!
Most open frame motors at this point in thier age have a weak field magnet, if your going to isolate the brushes and use the motor, I highly recommend replacing the field magnet. You can get small super Neo magnets from Micro-Mark and stack them where the old magnet was. You have to complete the "circuit" between the upper and lower motor frame, so if you have a small space between the magnets and the frame, a small piece of metal or a metal washer is needed to complete the magnetic "circuit". Its amazing how well one of these motors can run with a good, strong magnet in place. It lowers the amp draw, the motor will run cooler and it stores the low speed torque, enabling better crawling speeds. Mike the Aspie
Silly NT's, I have Asperger's Syndrome
When drilling in zamak (zinc alloy), a lubricant REALLY helps lessen drill breakage problems. Practically anything will do, from kerosene to heavy oil. A light oil like 3 in 1 would be my choice.
It's even more important when tapping.
Cleaning the cutting oil off later is irksome, which causes some people to try dry cutting. That's taking a chance.
"Do ya feel lucky?"
Thank you, Hornblower! A very useful and thoughtful reply. I have a few additional questions:
1. I am assuming that conversion to the NWSL 72:1 kit requires pulling the driver's off the center axle and replacing the gear. Correct? If so, will I need the NWSL Puller or similar tool?
2. The motor is the older open frame version, and while it seems to work well is fairly noisy, so I am thinking to replace it. It appears that a 15mm flat width x 20 mm x 32 mm can motor (NWSL 2032D-9) is the largest that will fit. However, it has a 1.75 amp stall current, and thus would requrie a 2 amp DCC controller. Would one of the slightly smaller NWSL motors (well under 1 amp) be sufficiently strong to power the locomotive? ( I don't anticipate more than a dozen or so cars behind it at any time, facing maximum 2% grades.)
3. Someone on this forum suggested reaming out the headlight with a small deburring tool on a Dremel tool, rather than using a drill. You've done this procedure; does the deburring tool seem like a good alternative to a "fragile" drill bit?
Thanks for all your help,
hornblower I've built two of the MDC 2-6-2 Santa Fe type kits (later versions with can motors and N/S wheels). The supplied can motors were single shaft so I replaced them with double-shaft motors and added a flywheel to one shaft. I also added NWSL 72:1 re-gearing kits, all-wheel electrical pick-ups on the tender, and operating headlight/reverse lights. If you try drilling out the existing headlight casting, go VERY slowly and lubricate the drill bit often. The biggest danger is breaking off a drill bit with it stuck in the hole! On the 2-6-2 Harriman style kit I built, I used magnet wire to simulate conduit to the headlight and powered it that way. The tender wheel pickups are simply lengths of phosphor bronze wire set in holes drilled horizontally through the center truck bolster with the ends rubbing against the axles for the uninsulated wheels or against the back sides of the insulated wheels. I was also concerned with how spartan the kit details appear, especially under the cab and around the trailing truck. However, searching the internet for prototype photos showed that the Santa Fe Praries were indeed rather spartan (see Gary's photo). I added DCC sound decoders in all three kits and painted/weathered them for my Santa Ana & Newport themed layout. It did take a little tweaking to get them to run as smoothly as I desired and to get the leading and trailing trucks tracking well but they are now some of the nicest locos I own. Best of all, I can point to them and say, "I built that!"
I've built two of the MDC 2-6-2 Santa Fe type kits (later versions with can motors and N/S wheels). The supplied can motors were single shaft so I replaced them with double-shaft motors and added a flywheel to one shaft. I also added NWSL 72:1 re-gearing kits, all-wheel electrical pick-ups on the tender, and operating headlight/reverse lights. If you try drilling out the existing headlight casting, go VERY slowly and lubricate the drill bit often. The biggest danger is breaking off a drill bit with it stuck in the hole! On the 2-6-2 Harriman style kit I built, I used magnet wire to simulate conduit to the headlight and powered it that way. The tender wheel pickups are simply lengths of phosphor bronze wire set in holes drilled horizontally through the center truck bolster with the ends rubbing against the axles for the uninsulated wheels or against the back sides of the insulated wheels. I was also concerned with how spartan the kit details appear, especially under the cab and around the trailing truck. However, searching the internet for prototype photos showed that the Santa Fe Praries were indeed rather spartan (see Gary's photo). I added DCC sound decoders in all three kits and painted/weathered them for my Santa Ana & Newport themed layout. It did take a little tweaking to get them to run as smoothly as I desired and to get the leading and trailing trucks tracking well but they are now some of the nicest locos I own. Best of all, I can point to them and say, "I built that!"
I think it would be easier to isolate the brushes. If it turns out they aren't already isolated. And if you wish to keep the old motor.
Perhaps the silicone does lessen motor noise. I would think it would. You could also put a neoprene pad under the motor to do the same think. Then you could still easily remove the motor if it were necessary.
You can isolate the motor by removing the attaching screw and attaching the motor to the frame using silicone. It will also quiet down the motor. It will work with DCC in these conditions, but you will need a 1 amp decoder.
I've got some old catalog sheets from Pittman. There's photos of their motors. It looks like most of them had brushes naturally isolated from the motor frame. Those would be DC-71B, DC-91, DC-60, DC-81 and various double-shaft motors.
The exception is the DC-70. It has a metal tab under the brush mounting screw that "grounds" the end of one brush tensioning spring. I expect the tab is easily removed.
I am not recognizing a "brass brush holder", as they all look like they're made of fiber/plastic. Thus making it easy to isolate the brushes. Something a metal brush holder has trouble doing.
"It certainly won't tell you much about how to build with and fabricate pieces from brass..."
True enough, but my interest is more in how to deal with DCC-ifying a metal locomotive model, how the running gear goes together, etc. Maybe I should have said "metal model locomotive" to clarify my knowledge gaps. I have some experience at fabricating fairly small sheet metal parts from other hobbies, and less about steam locomotives more generally and HO-scale practices in modeling steam locomotives.
I am not sure I understand how working with a MDC/Roundhouse cast metal kit is helpful to understanding brass locomotives. It certainly won't tell you much about how to build with and fabricate pieces from brass, because no cutting of metal and no soldering is involved with the MDC. The old MDC engines had brass driver tires and brass wheels if I recall correctly but that is about it.
Dave Nelson
Thanks to all for your thoughtful replies.
Since the Ottawa & Northern layout is DCC, is it possible to install DCC in the locomotive without replacing the OEM motor? My understanding is that open frame motors are not competely isolated from the frame, and thus cannot be used with DCC. Mel, your experience seems to indicate that it can be done. I will replace the wheelsets on the tender, but keep the OEM bogies.
Y'alll have convinced me to keep the existing drivers, and at least for now the leading and trailing trucks.
I have several options available with respect to the headlight, which I will ponder.
I'll stay in touch to let everyone know how the project progresses.
Lew Phelps
If you only run your locomotive during the day previous to about 1952, you don't need a working headlight or backup light, because they ran dark back then.
I've got a gas-electric that I'm running under those circumstances, and I expect I'll pass up the work it takes to light up the headlights. Plus I don't have to have "big" wires out of the back of the headlight.
I built several MDC kits. It is what I enjoy the most in this hobby... If I were you, I would start by changing the brass tender wheels. If the drivers are nickel plated, I would not change them.
For the headlight, you can drill a hole in the boiler and get the wire through there. It is a tedious job, but having an operating headlight will greatly improve the appearance of the loco. It's up to you (or the prototype you are modelling) whether you want to change the headlight or not. If it is compatible with your prototype, why change it?
Motor: the original open-frame motors were very good, but if you go DCC with sound, you might want to change it. NWSL is a great place to get motors and other parts. It will run smoother with a new can-style motor. If you think that you will stick with DC, then try the original one and see what you think. Given how old it is, you might want to add a drop of oil on the shafts before running it.
Details: that can wait for later. As others have said, build the engine first, see how it runs, and judge whether you want to add more details. I removed the molded details on mine and added new pipe fitings, etc. Results can be very convincing. But see if you like the running abilities of yours before going further.
Above all: Have fun!
LewPhelps1. Existing 63" driver wheels look to be black plastic with Nickel Silver rims. Should I replace with Greenway or similar wheels?
Depends what you are doing to mount the rods, if you want a small screw, the metal centers might be good. Measure the distance between axle slots, that's the absolute maximum for wheel diameter. If its less than the diameter of the wheels over the flanges then larger diameter wheels won't work.
LewPhelps3. Tender wheelsets and trucks are Roundhouse TR-303, an archbar style truck with brass wheels that have huge flanges.
I would use the arch bar trucks and use new wheel sets. I would add wipers on all the tender wheels. Use phosphor bronze wire or unfold the spring "ears" of a Kadee #5 coupler box spring to make wheel wipers.
LewPhelps5. The headlight, which is part of the cast boiler shell, sits in front of the boiler, on a "shelf" just above the firebox door. It's drilled out only about 1/3 of its depth.
You can add a lost wax casting or use the existing headlight. Get a very small surface mount LED (its a very tiny device). Get a MV products lens for the ight, use a ball cutter in a motor tool to make a small depression in the back of the lens (use masking tape to hold it while cutting) and glue the LED into the hole.
LewPhelps6. The tender has no backup light. Would a prototypical Prairie have had a backup light on the tender?
Yes.
LewPhelps7. Setting aside questions about super-detailing and paint/ finish/ weathering, am I missing/ forgetting anything important in turning this into a useful runner?
The hardest part of thise engines is getting the drive running smooth, getting all the binds out of the gears and side rods. Get that smooth and you have the biggest part of the battle.
Dave H. Painted side goes up. My website : wnbranch.com
I think you should build the kit "as is".
This will let you evaluate the running qualities.
You can watch it run for awhile, and also study the "look" of it.
Any mechanical/electrical improvements that you want to make can be combined with detail modifications.
Your questions about detailing are a matter of taste. For every addition that YOU want to make, you'll find someone who doesn't want to. Everything you propose sounds like a potential improvement, though.
Of course, with MY first steam locomotive kit, when I bought it at my not-that-local hobby shop, I spent more on Kemtron parts than I did on the locomotive.
LewPhelps I have a number of questions: 1. Existing 63" driver wheels look to be black plastic with Nickel Silver rims. Should I replace with Greenway or similar wheels? If so, would "medium" or "light" wheels be more appropriate for a Prairie? Should I stick with the kit's 63" wheel size or go a bit larger (given that Santa Fe, Great Northern and other lines ran Prairies with 69" drivers on the main line).
I have a number of questions:
1. Existing 63" driver wheels look to be black plastic with Nickel Silver rims. Should I replace with Greenway or similar wheels? If so, would "medium" or "light" wheels be more appropriate for a Prairie? Should I stick with the kit's 63" wheel size or go a bit larger (given that Santa Fe, Great Northern and other lines ran Prairies with 69" drivers on the main line).
You could try 69" drivers, but I would be afraid they won't fit. You could cut some cardboard circles that are a scale 69" + flange height, and place them on the drivers, and see what kind of clearance you have.
2. Leading and trailing trucks are both sorta cheesy, and the trailing truck in particular looks undersized. I'm thinking to replace both with Greenway or similar products. Any reason not to do so? What would be the correct wheel size for the leading and trailng trucks, assuming an ATSF prototype?
3. Tender wheelsets and trucks are Roundhouse TR-303, an archbar style truck with brass wheels that have huge flanges. Would a more modern style set of trucks under the tender be more appropriate? I'm thinking that any tender still operating in the 1950s would probably have been updated from archbar trucks. I'm also assuming that it should still be solid bearings, not roller bearings, even in 1954.
Archbars were still used for tenders in the '50s:
4. What's the best way to install power pickups on the locomotive and tender? I'm thinking about NWSL wipers, and also the fancier wheel wipers offered by SBS4DCC.com. Suggestions? Issues given that it cast metal locomotive and tender?
http://www.pacificcoastairlinerr.com/1905/tender_wipers/
Gary
Hello, all.
At age 75, I've just gotten into the hobby a few years ago. One of my interests is scratch building, and in particular working with brass. I'm currently building a '50s era flatcar in brass, working on a Pennsy N5C cabin car kit in brass, and...building out a brass Prairie 2-6-2 kit.
My railroad is a hypothetical midwestern regional line, the Ottawa & Northen, set in 1954, (roughly analogous to the Chicago Great Western).
This post is about my newly acquired MDC/Roundhosue 2-6-2 Prairie locomotive kit. To help me understand how brass locomotives work and come together, I recently bought this kit on eBay (MCD model number 6L1). It's party assembled (boiler and large cast body parts plus motor screwed onto the frame, drivers and trucks installed, nothing further.) The kit box has a price sticker of $32.00 dated 5-6-62, from "Stickler's Hobby and Tobacco Shop". (first two letters of the name are missing but I am guessing that's what it is.) Although this kit is "undecorated," and thus its prototype railroad is unknown, it appears to be based on the Santa Fe Prairies, including being equipped with an oil fuel tender rather than coal tender.
I'm planning to replace the open frame motor in the kit with a can motor and flywheel, and adding DCC with sound; I'll be installing the speaker in the tender. I have a number of questions:
5. The headlight, which is part of the cast boiler shell, sits in front of the boiler, on a "shelf" just above the firebox door. It's drilled out only about 1/3 of its depth. Any thoughts on how to wire this for an LED bulb? Or should I just grind it off and replace it with an aftermarket super-detail part?
6. The tender has no backup light. Would a prototypical Prairie have had a backup light on the tender? Photos I've seen photos of the ATSF Prairies showing a large backup light on the engineer's (right) side all the way at the back of the tender. Is that typical?
7. Setting aside questions about super-detailing and paint/ finish/ weathering, am I missing/ forgetting anything important in turning this into a useful runner?
Sorry for so many questions, but, as I said in the title, I'm a newbie at scratch building, and I figure it's better to get it all out there at once rather than creating a complex series of posts. Many thanks in advance for any advice offered.
Lew Phelps, Pasadena, CA
Ottawa & Northern Railway mid-50s