Best Of The Overland/Wiseman brass Western Maryland Shay thread

[mmagliaro]

I ordered 6 gears for about 33 bucks total with shipping and fees.

When they come in, I'll see if I can get some help with the tube.

Then see:

1.  If it will work- lacking the 10 degree angle
2.  How fast they wear out.  I'll install 2.
        a.  Shay with sound- continuous running on the flat level.
        b.  Shay Resurrected - continuous running on the torture grades.

I would say that if this gear works well and can last for two - three months running an average of an hour a day on the torture grades then it would be worth it.  If it lasts six months, I'd be in happier than a seagull with a french fry. 

(https://www.youtube.com/results?search_query=seagull+french+fries)

Sounds like a good plan.  What gear bore did you go with?
One really good thing about this is that you will not alter the screw hole.  So
if it doesn't work, you can always put the old gear back because you will not have made any permanent change to the chassis.
I'd hope it lasts a lot longer than that!  90 hours of run time isn't all that much to have to take it apart and change a gear.
What I'm hoping is that the Delrin is slippery enough to not wear at all and that it will protect the brass gears on either side of it.

[u18b]

I went with 1.8mm bore.

Though after I ordered, I thought I should have gone with 2mm simply because it opened the option of using a micro ball bearing bearing (as used in lots of hobby stuff like R/C cars, helicopters, drones etc) under the gear along with a small washer.

[mmagliaro]

Stainless capillary tube
https://www.amazon.com/Fly-Fiber-Seamless-Stainless-Capillary-Diameter/dp/B0868MRJK9

They have OD 1.8mm, wall thickness of 0.2mm, which will get the ID to 1.4mm, which should work well with your M1.4 screw.

Of course an m1.4 screw isn't perfectly 1.4mm in diameter, so just how perfectly centered the gear will end up over the original screw hole is an open question.  But that's splitting hairs  The original design relied on the head of a screw
inside a recess in the gear, and that's not very precise.   If you tighten the tubing down, but not all the way, let it run on the bench, and gradually tighten the screw as the mechanism runs, it will probably find its "happy place" where gears on each side of this Delrin gear have enough play in them to run well.

[peteski]

A straight-cut gear will not properly mesh with the worm.  Hopefully the Delrin will "wear-in" after a while, but then the teeth will be not as thick.  But I guess with the options currently available, this kludge is the best that can be done.

[u18b]

A straight-cut gear will not properly mesh with the worm.  Hopefully the Delrin will "wear-in" after a while, but then the teeth will be not as thick.  But I guess with the options currently available, this kludge is the best that can be done.

Yes.   I'm partially thinking of this as a Hail Mary pass.
If it works, great.

Other future options are to pay more money.  I'm sure I can pay someone out there to mill a gear with a 10 degree angle.  It will only be a matter of how much I want to spend.
 

But I view this as a good first step.

In many ways..... just like the brass EP-2..... I'm re-designing this locomotive.
Hopefully in a way that it is MUCH better than before (by the time I'm finished).

[garethashenden]

How much vertical space is there? Could the motor be moved upwards a bit? What I'm thinking is to have a double reduction gear drive, eliminating the gear/worm mesh issue. Replace the gear in the piston with a new straight cut gear of the same diameter. Replace the middle gear with a straight cut gear of the same diameter, meshed with the piston gear. Sharing the shaft with the middle gear, put a helical worm wheel above the middle gear. Mesh the worm with the worm wheel. If there's space this will give you an even greater gear reduction for slower speeds and eliminate the gear wear issue.

[u18b]

How much vertical space is there? Could the motor be moved upwards a bit? What I'm thinking is to have a double reduction gear drive, eliminating the gear/worm mesh issue. Replace the gear in the piston with a new straight cut gear of the same diameter. Replace the middle gear with a straight cut gear of the same diameter, meshed with the piston gear. Sharing the shaft with the middle gear, put a helical worm wheel above the middle gear. Mesh the worm with the worm wheel. If there's space this will give you an even greater gear reduction for slower speeds and eliminate the gear wear issue.

This is an interesting idea.  Thanks.

However, the gear reduction part is not for this unusual loco.
Right now, wide open it runs about 7.5 mph.

I wouldn't want it any slower.

[garethashenden]

This is an interesting idea.  Thanks.

However, the gear reduction part is not for this unusual loco.
Right now, wide open it runs about 7.5 mph.

I wouldn't want it any slower.

I get that. As long as the two spur gears are the same diameter as each other there won’t be any further reduction than the worm provides. But if you want more reduction you can put it in here.

[mmagliaro]

Using a spur gear as a worm gear means that essentially the worm will push all on one edge of the spur gear teeth as it goes around.  Theoretically, either the Delrin will wear, or it will be strong enough to not wear and the worm will just drive it by that one edge forever. 

But in practice, how well this will work all depends on how much slop there is in the mesh and how much load is actually on the gears.  In your case, the worm tooth angle is only 10 degrees and the spur gear is only 1.3mm wide.  There's probably enough slop that the motor worm teeth are going to hit the spur gear teeth somewhere in the middle and probably hit along a good percentage of the spur teeth rather than all along just one edge.

The devil's in the details.   If the load on the gear isn't too high, it will work and won't wear out.
If you really want to experiment, you could try ever-so-slightly angling the mount of the motor so that you cancel out its 10 degree tooth angle at the spur gear.

[u18b]

If you really want to experiment, you could try ever-so-slightly angling the mount of the motor so that you cancel out its 10 degree tooth angle at the spur gear.

Now that's an interesting thought.

And I should be able to do this once I get the gear.

EDIT:     PROCESSING........


Since I have Beardenized it.... and since the outboard bearing has a ball in it and pivots...
Then I should be able to lower the outboard bearing by removing the red paper washer ...
And raise the motor -- though this will be  harder.

I'll have to find a way to support the motor.
And the decoder will need to be relocated since it will run into the roof of the coal bunker.
I may be able to move the decoder to below the motor.

And I may not need to raise the motor 10 degrees.
7 or 8 may be sufficient.

Experimenting with all this will be a whole lot easier in analog configuration without the decoder.

And by the way.... the way I want to run this Shay is definitely HIGH load.

[u18b]

Let's think this through.
Because the Cylinder Head gear has angled teeth too.

And since we cannot change that, we should start THERE.

Look at this picture and imagine standing and looking from the bottom of the view.



So if we are looking from the LEFT side of the loco... in the back of our view we would see this.



And to match that angle, I would need to angle the straight gear I am getting created in Poland. 
My rough estimation (using Corel Draw and photos- thus some human error), the gear would need to be raised in the back by 5- 6 degrees.



Seeing what to do with the worm is more complicated.   I'm not good at thinking 3 dimensionally (was never good at carving in Boy Scouts).

Would the worm need to be raised as well?
or not at all?

[mmagliaro]

I think if you angle your straight gear, that will make it right with the motor worm and the motor doesn't have to move.
But yeah, this will be a lot easier to figure out when you have the straight gear in there and you can see how the teeth actually fit together.

So tell me about that cylinder drive gear.  Why can't that one be changed?  Is it because it is soldered onto the end of a
stem, or cast as one piece with a special stem that goes up in the cylinder mechanism?  That's what it looks like.

[u18b]

Yes.  Soldered onto the shaft.

But obviously can be un-soldered.

If angling the new worm gear is too much of a challenge, I guess I could always go back to Poland and get a new brass gear.
Maybe that will match better.

Now comes the hard part-  waiting for the mail to come from Poland!

[mmagliaro]

Yes.  Soldered onto the shaft.

But obviously can be un-soldered.

If angling the new worm gear is too much of a challenge, I guess I could always go back to Poland and get a new brass gear.
Maybe that will match better.

Now comes the hard part-  waiting for the mail to come from Poland!

Can you remove that whole gear and the shaft it is soldered to, as a unit, so you could un-solder the gear from it on the bench?
Or do you have to unsolder it in-place on the engine?
I guess I'd see how it goes first.  But if there's trouble between your new center gear and that crankshaft gear, angling that center gear is not going to be easy.  You would have to re-drill and tap the hole under it at an angle to mount the bearing tube at an angle.
It might be easier to unsolder that other one and replace it with a straight-toothed gear.  Then you can accomplish any angle fiddling (if you have to) by angling the motor.

Boy, no matter how you slice it, this gear train was not designed with lifespan or serviceability in mind.

[u18b]

Must be unsoldered in place (and that can be a little tricky.).

So the worm with shaft slides up from the bottom.  You then install the gear onto the shaft and solder it onto the soft steel shaft.



But, it would not be THAT big a deal to get it off.