Athearn worm gear thrust washer


flyboy2610

flyboy2610

Loveably weird
I really should learn to finish one project before starting another. Oh, well.
I have an Athearn SD-9 locomotive that I installed a Digitraxx decoder into many moons ago. (It was my first install. While functional, it's not real pretty. It's being re-done.) I am cleaning and re-lubing the drive gear. This locomotive has always been a bit noisy, and I think I may have found one of the reasons why: It's missing a thrust washer from one of the worm gears. This loco has a 'modern' sealed motor with dual flywheels, so it's not noisy due to an open frame motor. I think the worm gear is moving back and forth causing the noise. I need a thrust washer in that gear tower. The problem, as you may have guessed, is: Athearn no longer MAKES these washers! :mad:
Doing some research for a source for these washers, I've come across a couple of sites where people have stated that a #2 flat washer is perfect for this application. I have a good supply of #2 flat washers, and the ID and OD are spot on! The only difference is thickness. The thrust washer on the driveshaft side is .011", and the thickness of a #2 flat washer (at least the ones I have) is .016", for a difference of .005", which is not quite the thickness of 2 sheets of notebook paper.
Do you think this is going to be enough to cause problems, or should I be OK to go with it?
I've looked around, and I can't find anything closer that what I have.
This is the worm gear. The driveshaft side washer is .094" ID, .221" OD, and .011" thick. The black oxide #2 washer is .094" ID, .217" OD (not enough to worry about) and .016" thick. I'm thinking it should be OK, but what say ye?
004.JPG
 
Without popping one of my Athearns open to look, I seem to recall just a little bit of play in the towers. I would think you should be fine adding .005" thickness. Pop it in, put it all together and see what it looks like. Worth a shot, I figure.
 
I remember Kadee used to offer spacer washers.

I may have one or two of the Athearn ones floating around, I can look in my junque box and see.
 
KB02 said:
Without popping one of my Athearns open to look, I seem to recall just a little bit of play in the towers. I would think you should be fine adding .005" thickness. Pop it in, put it all together and see what it looks like. Worth a shot, I figure.
Click to expand...
Yea, that's probably what I'll do. The gear does have a little play in it.
 
bnsf971 said:
I remember Kadee used to offer spacer washers.

I may have one or two of the Athearn ones floating around, I can look in my junque box and see.
Click to expand...
I know they still make fiber washers for installing under the trucks to adjust coupler height. If you could look in your treasure box, that would be great. I think I'm going to install this washer and see what happens.
 
Kadee makes a number of washers, fiber, metal and plastic. #208 red fiber is .015", while #209 gray fiber is .010". I have used both to shim up Athearn driveshafts. Unfortunately their website does not give a thickness for their metal washers. If you already have the #2 washers, they should work, as I use mostly the red ones myself.
 
This post doesn't deal with the thrust washer specifically, but I thought I'd post the final installation of the decoder.
I made all the motor connections and secured any excess wire to the side of the motor. The #2 washer is located in the gear tower on the left hand side, which is actually the rear of the locomotive. Union Pacific ran these early diesels long hood forward. I have the shell backwards in this pic. If you look closely at the mounting pins on the side of the frame, you will see they do not match up with the holes in shell this way. Turn the shell around and they fit perfectly. You can also see my custom built light harness. The 9V battery was used to make sure the grain of wheat bulbs were still functional. They were. The end of the clothes pin has paint on it. It's not charred!
001.JPG


When I first installed this decoder, I made some light enclosures out of styrene. Look close and you can see the holes for the bulbs.
003.JPG


The first time I did this install, I did not use resistors for the bulbs. When I bought them, my LHS owner, Randy, told me they were 16 volt bulbs so no resistors were needed. When I tested them with the 9V battery, I thought they were pretty bright even at that voltage. I put the loco on my test track and turned on the headlight. I held the wires together in my fingers, and at 16 volts they were WAY too bright for my liking! I also have some 680 Ohm 1/4 watt resistors, so I decided to put a resistor in the lighting circuit. I have always heard that with an LED the resistor should go on the negative lead. But GOW bulbs do not HAVE positive and negative leads. They are not polarity specific. The blue wire from the decoder is the positive, and I had (in my previous install) used some colored electrical tape to mark which wire went where for the lights. Question: should the resistor go on the positive or negative lead? Off to the Wonderful Wide Web I went. After much research I discovered: it doesn't really matter. At the voltages we are dealing with here, either will work just fine. If I put the resistor on the blue wire, I only need 1. If I put the resistor on the yellow and white wires, I need 2. I would rather deal with only 1, so onto the blue wire it went!
004.JPG


I put the loco on the test track and checked the lighting circuits. This is when I discovered that in order to have the light on the long hood come on when the loco is in forward direction, the yellow wire light has to be in that hole. When Athearn produced these, they set them up so the short hood is forward. But UP ran them long hood forward, a holdover from the steam locomotives I suppose. The white wire light is supposed to be the front light. But that light comes on when the loco is in reverse, so it has to go in the short hood. Putting the yellow wire light in the long hood solves the problem. I also had to program the decoder to swap forward and reverse, but it's all good now!
I held the lights in the enclosures with some hot glue. The only reason I did this is because I have a dual temp glue gun. I used it on the low setting. I didn't want to find out what hot glue might do the plastic. I put the bulbs in their enclosure, pushed the all the way forward, then pulled them back about halfway and glued them in. I tried to keep the bulbs from direct contact with the plastic.
005.JPG


In the above pic, you can see that the decoder is mounted upside down. I had to do that because when I mounted it right side up, I couldn't get the shell on. I am somewhat concerned about having the electronic components facing the double sided tape. I know the decoders do produce some heat, and I don't want it to get too hot and burn up. Here's what I mean:
006.JPG


I can't use double sided tape and fasten it to the top of the shell because the power wires aren't long enough. I could remove the decoder and double sided tape and just let the decoder "float" in the front of the shell, but then I have no way of ensuring that the decoder or wires will not contact or entangle in any moving parts. What do you folks think? Will it be OK like this? Will it dissipate its heat OK?
I've only run this on the test track with the shell on long enough to make sure everything functions properly and to set the motor CV's. With CV 2 at 55, it starts out nice and slow at speed step 1. It runs really nicely! I'm happy with the locomotive, but do plan to add some additional pick up wires. I found this video:

I don't plan to polish the wheels, as they have long ago been replaced with nickel silver wheels. It sounds as though polishing only has an advantage if the loco still has the original sintered metal wheels. But the additional pick up wires would be a neat addition.
Last night, while I had this all apart, I took the plastic truck sideframes and the metal loco frame outside and gave them both a couple quick shots of Rustoleum gray primer and rusty metal red primer, just to dirty them up a bit. They still need a bit of work, but they look better than they did!
I still need to lightly weather the shell. Athearn calls this an SD9, but UP 457 was actually an SD7. I remember Randy telling me that this model is really not an accurate representation of either, but more of a 'fooby'. Either way, in the period I "model" this would still have been a fairly new locomotive, so it wouldn't be all rusted, patched, and looking like a refugee from the scrappers torch!
 
Flyboy: Many of my local hardware stores have bulk nuts, bolts and washers. Maybe you could find an exact replacement.

Greg
 
Greg@mnrr said:
Flyboy: Many of my local hardware stores have bulk nuts, bolts and washers. Maybe you could find an exact replacement.

Greg
Click to expand...
Hi, Greg! #2 hardware is pretty sparse in the hardware stores and home centers around here. Menard's has some, but not much, and what they have is in small plastic envelopes. I installed the #2 flat washer, and it seems to be doing OK.
I tried removing the decoder from on top of the motor and just letting it 'float' in the cab, but the loco did not run well at all. It took a pretty high throttle setting before it would move, so I think something was binding up in there. I re-installed in on top of the motor with a single layer of double sided foam tape, in the same orientation as it had been. I replaced the shell, put it on speed step 1, and it crept forward, so I know nothing was binding anymore. I programmed CV #2 to 75, #5 to 255, and #6 to 128. It responded as I wanted it to.
Next, it needed some couplers, because a locomotive is pretty useless without those! Kadee recommends #38 coupler assemblies for this loco. I don't have those. I decided to try a #148 in a standard gear box. The coupler was too low and the gear box too long. I needed some 147's. I had 1 on hand. I found somewhere where Kadee said an alternate setup would be a 148 or 147 in a 252 draft gear box. I already needed some 147's, so off to Randy's Roundhouse I went. He had the 147's, but no 252 gearboxes. He told me that what he does is cut the back of the 147 box short and round off the corners. So that's what I did, and now it has functional coupler of the right height. Off to the layout we go!
I put it on the track using the re-railers just before the bridges, and gave it some power. It made it halfway around the mainline and stopped on a Peco turnout frog. I nudged it, and it took off again. Until the next Peco turnout, where it shorted out the PowerCab. I reset it, and it made it to the first turnout of the double crossover, where the front truck continued on the mainline, and the rear truck tried to take the passenger siding. I tried 2 or 3 more times to get it to go around the layout. It exhibited the same behavior in each spot, but ONLY in those spots. The SD45 had run around the layout forward and backward just as happy as a tornado in a trailer park, so I could be fairly confident that the track wasn't the issue.
I watched the wheels very closely in those spots. At the first Peco, I couldn't see anything happening. At the second, I noticed that the rear truck seemed to not be able to swivel quite as far as the front one did. I wondered if that may have had something to do with the locos behavior at the double crossover. I took the loco off the layout and examined the trucks. It looked as though the plastic upper brake bracket detail might have been rubbing slightly. I pulled the sideframes off and used a flat sanding block to round off the corners of the brake brackets. I though about cutting them off, but didn't want to do that unless I had to. As it turned out, rounding off the corners of the brake brackets did the trick!
I put the loco back on the layout, gave it some power, and round and round it went! After about 10 laps, I decided I had fixed the issue! I put together a 15 car train, and for the next hour straight the loco pulled the train around the layout just slicker than snot on a doorknob! After an hour, I turned the loco around, put it in reverse, and it pulled the train 'backwards' for the next hour and fifteen minutes! So that was nice! :)
I also took it through the passenger siding several times each direction. No issues! I did have to tweak a few things on a few of the cars, but the loco ran great!
 
So far as thrust washers are concerned, have you checked with North West Short Line (NWSL)? They have a bunch of different ones.
 
You must log in or register to reply here.



Back
Top