Best Of The Overland/Wiseman brass Western Maryland Shay thread

[peteski]

Love the way you sugar coat it... I remember thinking all the red paint was rust 

But brass doesn't "rust" in iron's "rust" color.   

[Chris333]

I saw it mostly on the truck bevel gears and though it was on a steel shaft.

[u18b]

I now have a running model.  It doesn't run very well- but it runs.  Considering this arrived DOA, this is progress.

Here is a video of the stock mechanism running.    The worm misalignment is terrible.

And here is a video showing why these locos derail so badly.   The torque stress is very hard to overcome and often causes derailments- as in here.



Here is the video.  Pay attention to the truck on the left- the main drive trucks.  Watch how the torque pivots the truck when the direction is changed and power applied.

[u18b]

Remember, that one of the common problems with a version 1 Shay is that the lineshaft on the rear cab truck is too short.  The square tube is attached to the crankshaft.  It is so frustrating when the pin pulls completely out of the square tube simply from handling the loco.   This should not happen.

In this photo, the shaft on the left ends at the pink line.   The wasted space is at the blue lines.  The green line is the maximum the pin can go.    You do NOT want the pin in it’s straight/neutral state to go all the way to the green line.   The reason is because when the loco is on track the curves to the right, the wheel in the photo goes down and the pin goes deeper into the square shaft.  On your tightest possible curve, the pin can go to the green line.  However, the pin SHOULD go to the right side of the blue indication.


 
So what I want to do is add a piece of shaft to make it longer.  I don’t need much.  I want to make the pin come to the right side of the blue shown above.

I had a spare piece of shaft.  Obviously, in this photo, I’m going to mate the flat edges (not the cut edge)



To possibly make the joint a little stringer, I made some micro cuts in the new shaft and the old shaft.   I hoped this will create more strength because of the twisting force applied.



I fluxed, tinned, and pieced the parts together with my resistance soldering tweezers.   I held the new piece in the tweezers and got the new piece hottest.  When soldered, I trimmed the extension and filed it smooth.   I guessed on the length.  If it was too long, then I would trim some more.



Now, when I place the loco on the tightest curve, the new pin bottoms out at the green line.  Thus when the truck turns in the opposite direction, the pin does NOT pull out of the socket.  Problem fixed.

[Chris333]

So you're saying there's a chance.

How much does the center truck even need to pivot? I mean could you just pin it in place and let the rest of the loco steer?

[u18b]

So you're saying there's a chance.

How much does the center truck even need to pivot? I mean could you just pin it in place and let the rest of the loco steer?

Not sure, but it definitely needs to pivot.

[u18b]

Time to replace the stock motor.

The stock motor is too weak, too loud, too fast, and probably a 3-poler.

I use the same great coreless motor that I buy from Tramfabreik.
http://tramfabriek.co.uk/motors.html#motors

I use the one described as:
0716D - 12V Coreless Mini Motor 7 x 16mm (Dual Shaft)
Diameter casing: 7 mm - Length: 16 mm - Shaft diameter: 1 mm
Shaft length front: 5.3 mm - Shaft length rear: 5.0 mm
Rated speed: 11,000 rpm - Rated current: 40 mA

I also buy the shaft adapter.  Since the shaft is 1 mm and the gear I use is 1.5mm.
AD1015 - Brass adapters for worms and gears with OD 1.5 mm
Outer diameter: 1.5 mm
Inner diameter: 1.0 mm

The new nickle silver worm comes from Japan.
http://www.narrow-garage.com/NarrowGarage.html#M0.25
Order part # NG-P200
http://www.narrow-garage.com/29792979.JPG
The worms are pretty cheap, but the shipping is really high. Packages arrive quickly.

First, I get the old worm out.  Pull the u-joint off and spread the brass bearing holder tabs.



I then rocked the tabs back and forth and broke them off.



Made a motor housing from K&S brass tubing.



I wanted to move the motor closer so I drilled a new passthrough hole in the motor mount bracket.



I then installed a screw through the new bracket hole into the stock hole in the frame.  By mounting as shown, the motor can now pivot around this screw (red).  This is important because my worm is a little larger and the motor different.  We want to be able to get the worm mesh perfect.   I then guesstimated a new hole to drill in the frame when the motor was oriented about right.   I used a Sharpie to mark the frame through the bracket hole.   This gave me a spot to drill and tap for a new screw (blue).  The last step was to enlarge the blue hole in the bracket since the blue screw is fixed- allowing the whole motor bracket to pivot.  When I get it all just right, I tighten the screws to lock it down.





Now I can get the mesh just the way I want.



now, you can see from that photo that my worm is too low.  So I soldered two washers as shims to raise the motor.

Making progress!

[u18b]

Now that I have the new motor working, I cut of the extra rear shaft.



Time to deal with weight- which is more important in a ver 1 Shay than ver 2 because of the torquing by the main drive gear.

The weight in the coal bunker was soldered and permanent- but I wanted to not go back to permanent.  So I shimmed one side.  The best side to place the weight is the side with the cylinders (engineer’s side).



A well-sized square of styrene holds the weight and keeps it from rattling.



As I did on the last Shay, I melted CerroBend 158 into the boiler.  Of course, BEFORE I filled the boiler, I installed the retaining screw under the boiler nose (otherwise, how would you get the screw in later?).   The front nose boiler plate was tight on this model, so I did not need a PlayDoh dam, not did I install a light tube. 







If I ever decide to install a light tube, the CerroBend could be melted out and re-done.  (before painting of course).

[u18b]

2 steps forward, 1 step back.   All modelers should be warned that these are magnificent-  but finicky locos.  Maybe that’s because a Shay is a complex loco by nature.

I make an improvement and feel satisfied with the way it’s running.    But then it cogs again and I breathe heavy.

Persistence is required to own this model.  And I hope this thread helps.

When this version 1 loco cogs (or locks up), it is the little pyramid gears malfunctioning and not properly meshing with the crown gear on the  wheels.   I’ve dealt with this before in version 2 Shays, but this is far worse.  And I think I figured out why.

Its a design problem.  Study the next photo to see the problem.



The key interface that makes this loco run is the tiny pyramid gears meshing with the crown gear on the wheels (yellow).   The side of the crown gear is the common side and conducts that pole of electricity through the whole loco, while the opposite side is the insulated side.

Of necessity, there is a pick-up that wipes the back of the insulated wheels (blue). 

But as I said before, this version 1 wiper is stiffer than the ones used by the version 2.  This pushes the axles AWAY from the pyramid gears (pink).  This is exactly what we DON’T need.

This is bad- we need those wheels tight to the pyramid gears.

Thus my solution is to place a wiper on the crown gear side and press the wheels closer to the pyramid gears.  In fact, I’m going to make a swap and move the stiff pick-up to the geared side and place a softer pick-up on the insulated side.

But the problem is the tabs which hold the cross supports.  The main drive truck does not have cross supports like the front truck or tender.  But I will use the support BRACE (or tab). 

In the photo below, you can see that the tab/braces are two lengths.   The full tab is pink.  The yellow tab is trimmed.   So I need to trim the full brace so the pickup can be mounted there near the geared wheels.  Notice the holes are already threaded.



Trimming that tab requires disassembly.  This is accomplished by removing the screws which hold the sideframes- which you can see in this photo.  As built, the screws are soldered down and it might require work to get them free.



Here is the finished process.   The stock heavy pick-up has now been mounted on the tab so that it wipes the  geared wheels and PUSHES them toward the pyramid gears and keeps the interface nice and  tight (blue).   I then mounted a spare version 2 thinner pickup in the stock position pushing (gently) on the insulated side (pink).



This change made a great improvement and corrects a slight design flaw in this loco.

[u18b]

Now that I have this Shay running better, I’m detecting some shorting issues.
Often this is the tender steps touching the rails where the track is a bit uneven (like around turnouts).

I’ve seen this before but want to solve it.  In the past, I have taken a motor tool and trimmed the bottom rivets off of the steps to give more clearance.   But I’ve discovered something better.

Here’s a short problem solving video.
More to come.

[u18b]

I’ve discovered a “two for the price of one” solution.

Problem 1- the steps on the tender have a tendency to short out.  They just get too close to the track. 

Part of the issue is that there is a bit of slop in multiple places.  There is some excess play in the axles themselves where they slip into the bearing holes in the sideframes.  There is some play between the truck frame and the bolster and some play in the screw and the hole that it goes through.  Finally, the drawbar slot has a good deal of play.

The end result is that the tender can be a little wobbly- especially forward to back.  In particular, when the nose rises, the rear steps go down and a short happens.

A simple testing solution is to place an extra weight on the front of the tender.



The weight in the tender is balanced over the retaining screw.   But it is actually helpful if it is NOT balance and there is more weight up front.

It suddenly occurred to me- this may help with problem 2 as well.

Problem 2- the main drive truck gets a lot of torque and the wheels can derail.  Extra weight helps hold the truck to the rails.

In that photo above, this big weight is holding the front of the tender down, but it is ALSO pushing down on the drawbar.

Since the rest of the tender is hollow, the solution is to add more weight to the front 50%.

The first step is to get that weight out- which is very hard.  Tedious scraping can get it free.



With the tender standing on end- nose down, I then used a soldering iron to melt some CerroBend into the front cavity.



I then added some alloy to the front sides.  If I added too much and could not get the weight back in, a motor tool easily removed excess.  Though not shown, I installed the screw in their holes so the alloy would not make an obstruction.







When finished adding alloy, I reinserted the weight and used some painter’s take to hold it in and prevent rattling.




Now, when all reassembled, the tender nose pushes down on the cab drawbar and the steps no longer short.

[u18b]

After continually perfecting this locomotive and test, and re-test.  It runs great! 
I’m excited…. And then I cogs and locks up again.   Ahhhhrrrr!!!!!  (I thought I fixed that!).

I decided more drastic investigation was called for and I made a shocking discovery.

The issue is always the main drive truck under the cab.   This is the truck with that butchered journal cover.   I had a spare journal cover and was going to replace it one day.  So now is the time for deeper investigation.



Resistance soldering tweezers will pull the journal cover off easily.
Once that’s done, the driveshaft can be removed.



I examined the driveshaft slots and found they were not identically square.
The rear slot was fine.  And there was very little play on that end before disassembly.



But the front slot was NOT square and was a bit rounded from excess wear.  OK- this is why there was some excess play on this end.   

But the worst is still to come.



On the troublesome end, the little pyramid gear actually has a chunk missing from one of the teeth!  THIS (along with the extra play) is why this loco occasionally cogs and locks up.    Epic fail.   



And by the way, I also saw why there was some excess eccentricity in the u-joint.   The fork is soldered on crooked.




Well, all the changes I made to this point helped, but nothing can cure this except a transplant.
Thankfully, I had a few options.   I had an extra tender truck- so that was a source for parts- especially to replace the damaged sideframe.  And I had an extra pyramid gear.

But the main drive truck has a different bolster- so that will have to be swapped.
In the photo below, you can see the bolster I need to get off and move to the new truck (pink).
Since the sideframe of the stock truck is damaged, I will not re-use it (red). 



I then completely disassembled the extra tender truck and installed the required bolster on it.



I then had to replace the damaged pyramid gear.  Thankfully I had a spare.  I could not simply use the shaft from the tender because the tender shaft only extends forward.   The cab truck must extend forward AND backward with a longer shaft.

So I installed the new pyramid gear getting everything in the right position.



And then installed the journal covers (one of which was a replacement for the damaged one).



When I got everything back together, I FINALLY was able to stop the cogging. 

Success!

[mmagliaro]

As always, Ron, beautiful, detailed and PERSISTENT!  (LOL!)

About the truck wipers that you changes to keep the crown gear engaged, I had a thought...

Couldn't you have just put some Delrin washers
on the outside of the wheels that are on the opposite end from the crown gear, to keep those wheelsets firmly pushed toward the gears?  They would have to be selected well, to just leave a hair of play so everything works smoothly, but it seems like it would be a simpler than rearranging all the pickup wipers, and more consistent.   I worry that over time, those wipers won't always maintain the same pressure and those gear teeth could skip.

[u18b]

As always, Ron, beautiful, detailed and PERSISTENT!  (LOL!)

About the truck wipers that you changed to keep the crown gear engaged, I had a thought...

Couldn't you have just put some Delrin washers
on the outside of the wheels that are on the opposite end from the crown gear, to keep those wheelsets firmly pushed toward the gears?  They would have to be selected well, to just leave a hair of play so everything works smoothly, but it seems like it would be a simpler than rearranging all the pickup wipers, and more consistent.   I worry that over time, those wipers won't always maintain the same pressure and those gear teeth could skip.

Yes, Max.   That's a good idea.   The problem is size (as you indicated).   I did have a few washers that are thrust washers from Atlas and Kato locos.  But of course the inside hole diameter must be perfect.   I'll have to post a shot of what we are dealing with.  Maybe even a drawing.

Even metal washers are possible- as long as they are the perfect size.  Otherwise a short will occur.

But there is actually another reason the wiper- though not perfect- is a benefit.   The electricity for one pole runs from the wheel tread with the crown gear to  it's central axle post which fits into a bearing on the sideframe.  That's it.   All electricity flows through that point to the frame.   Well, this loco needs an above average amount of lubrication (like the real thing).    I seem to remember someone asking me about that many pages ago.

Many steam locos have a few siderod parts that are load-bearing- the rest are more or less ornamental.  But in this loco, all of the moving parts are load bearing- thus the explanation of why I lubricate these locos well.

A wiper on the back of the wheels with crown gears provides an alternative route for electricity in case oil fouls the bearing (the stock route for electricity).

[u18b]

I’m preparing a detailed truck analysis and tuning section. But until then, here are a few loose ends.

 I noticed that the pilot on the rear of the tender was crooked.  You can see it in the points where it mates with the walkway.



Closer inspection reveals a build error.  The worker did not remove the casting sprue.



So I removed the pilot.



Now I can get at it to file it down.   The pilot was added back with all the previously described solder reinforcement to make the bonds stronger.

The other issue is common- since it is a design flaw.  The power reverse is the large piston under the cab.   Its position may be fairly prototypical, but it becomes an obstruction for the pivoting of the truck.  I can become a contributor to derailments on curves and turnouts.

Notice the ball shaped mounting point.  I cut that about in half to raise the power reverse. 



There is a mounting bracket with a slot in it on the back side.  I also cut the slot on the bracket deeper. 
When it all looks good, I solder it in place.    It might be a tad too high, but the obstruction is gone.