Best Of The Overland/Wiseman brass Western Maryland Shay thread

[rodsup9000]

Tail stock holds flat until dry. This technique is often used in clock and watchmaking.  I expect there is a indicator tip to facilitate measuring run out  of the gear.

Duh, I wasn't thinking of that. 

[mmagliaro]

I had forgotten that these particular gear has that raised smooth area behind it.
Yep... That's where I'd bet my chips.  I could certainly grab that in a collet, and then drill.

[u18b]

I re-measured the gear, and my first measure was correct.

The worm gear measures 4.99 mm.

According to this nice gear calculator I came across....
https://www.technobotsonline.com/gear-size-calculator.html

Enter
4.99 mm
and 18 teeth....

and you get nothing.

But the teeth are probably worn a bit....  so enter 5.00 mm with 18 teeth...
And you get a mod size of .25

I went to a local machine/CNC shop today in town.
I asked if they can make gears.

They can--- if I buy about 1,000.
 

[u18b]

I liked Chris' suggested website.  Thanks @Chris333

http://www.narrow-garage.com/NarrowGarage.html#Gear

I need a right hand worm.
and a right hand gear.

They don't have exactly what I have, but I'm guessing all  mod .25 gears work together, no matter the size or number of teeth.

I translated what I think I want from their page.  Here's what I'm probably going to order.

NG-P202H
M0.25 Right helical gear with 20 teeth. Made of phosphorus bronze. Outer diameter 5.5 mm, reference circle 5 mm, shaft hole diameter 3 mm, length 2.5 mm Contains 2 pieces.      550 yen

NG-P201H
M0.25 Helical gear with 16 teeth. Made of phosphorus bronze. Outer diameter 4.5 mm, reference circle 4 mm, shaft hole diameter 2 mm, length 2.5 mm Contains 2 pieces.       506 yen     


NG-P200
M0.25 right worm gear. Made of nickel silver. Outer diameter 3.4 mm, shaft hole diameter 1.5 mm, length 5 mm Contains 2 pieces.      528 yen

You can also buy one worm and gear set:
NG-P201      770 yen
NG-P202        792 yen

As far as very very rough estimating of price, 1 Yen is in the neighborhood of a penny.    So 528 Yen is about 5 bucks.

So for about $31 plus shipping, I can get:

4 worms and 3 of each gear.

The nickel-silver worm is a different material (good) and it is almost identical to the Atlas worm I just installed as an experiment.  Same diameter (3.4 mm) and same 1.5 mm shaft.  It’s a little shorter (5 mm vs 7 mm).  This worm will be larger than the stock worm.

Now, since these gears are not the same exact size as mine,
there may be fit issues.   By getting a gear larger than mine and smaller than mine, it might be that one may just work.

But if not, the mounting screw hole will need to be moved.   To do that, I would just create a new mounting plate.

[peteski]

5.5mm with 3mm hole, and 4.5mm with 2mm hole? Interesting. Those gears seem to have rather large holes.

[Chris333]

They are holding an order for me right now till next week to get something else in stock and just ship once. Shipping is 3000 yen for my order. So you need to keep that in mind. Takashi Tsukuno is who I always end up talking to. He even ordered in other products from Japan that he doesn't carry at his shop and sent them to me.

You might try looking on ebay:
https://www.ebay.com/itm/165022701066

[u18b]

PM sent, Chris.

[u18b]

Once again, for documenting purposes:

The stock Overland Shay items are:

Worm, right hand, 3 mm dia, mod .25
worm gear, helical, right hand, 5 mm dia, mod .25, 18 teeth
Cylinder head gear, helical, left hand, 5 mm dia, mod .25, 18 teeth.

I've begun to learn a bit about gears from this project.
For example, module calculation  mod=outside dia / teeth
a calculator: https://www.technobotsonline.com/gear-size-calculator.html

Also, right and left hand:

[u18b]

5.5mm with 3mm hole, and 4.5mm with 2mm hole? Interesting. Those gears seem to have rather large holes.

Yes they do.

But that's good if a brass tube insert will be used.

Also, the 3mm hole is awfully tempting for me to add two  1x3x1 mm ball bearing micro-bearings.

Since Chris has an order awaiting a part, he's graciously letting me tag onto his order and I'll split the shipping with him.

[u18b]

At this point:

--I'm doubtful the spur gears from Poland will be helpful.   But I'm still interested to see them when they come in.

--Good solution 1:   Send the worm gear to someone to drill out for K&S brass tubing.  Then, stock frame screw hole will be expanded from M1.4 to M1.6.  Gear will be mounted with washers, M1.6 screw and a tube.   A nickel silver worm  will be added with the 1.5x3x2 bearings with scratchbuilt bearing retainers- this worm should be more enduring than the brass worms that die there.

--Good solution 2a (doubtful):  One of the new Japanese gears works in the stock mounting holes.  Mount new nickel silver worm on bearings with retainers.

--Good solution 2b: create a new motor mount plate (3/64" brass).  Drill new holes for Japanese  worm gear and bearing retainers.    Mount new worm and gears.  I like using the smaller 16 tooth gear to give just a little more speed.  Right now the little coreless motor pushed the Shay at a max speed of about 7.4 smph.  Adding a smaller gear will increase that just a tiny amount. (say about 11% to 8.5 smph)

Since I have more than one Shay, I may try both solutions.

[mmagliaro]

I re-measured the gear, and my first measure was correct.

The worm gear measures 4.99 mm.

According to this nice gear calculator I came across....
https://www.technobotsonline.com/gear-size-calculator.html

Enter
4.99 mm
and 18 teeth....

and you get nothing.

But the teeth are probably worn a bit....  so enter 5.00 mm with 18 teeth...
And you get a mod size of .25

I went to a local machine/CNC shop today in town.
I asked if they can make gears.

They can--- if I buy about 1,000.
 

They are just doing this:
mod x (numTeeth + 2) = outer diam

or
outer diam
--------------         = mod
(numTeeth + 2)

4.99
-------    = mod 0.2495
18+2

Clearly mod 0.25  Their web calculator is just being fussy.

[u18b]

I have a little to report.

The gears from Poland were delayed for some reason.   They appear to have shipped last week.

A while back I received a worm from Gene Maddox- the Hallmark parts guy.
This is not a permanent solution because the worm is made of brass, but it IS a temporary solution.
Unfortunately, the shaft for the worm is of a weird size.  (not 1mm and not 1.5 mm).   If I was going to use it, I would have to either use the Samhongsa bearings or drill out the worm for a 1.5 mm shaft.





I guess this is a no brainer for a lot of people but I was slow to come to the realization of the problem.  The worm gear has 18 teeth.  So the worm spins one complete revolution to move 1 tooth.    Thus, the worm spins 18 times for every one time the gear spins.     Thus this is why the worm wears out but not the worm gear when both are made of brass.


And that leads to the best news.
The parts arrived from Japan.

I ordered nickel silver worms and two sizes of gears.


Because these have the same module as the worm gear they should work well.
Not sure I'll use the gears, but the worm is the best item.
Since it is harder than brass, this should solve the wear problem.

I'll be tinkering in the coming days.

Today, I send Max my worm gear and he is going to drill it out for a brass tube sleeve or bushing.  This should make this gear more true.  Right now, it has an eccentric hole worn into it and thus it wobbles when spinning.  And thus makes a lot of noise.

I still have some waiting, but we're moving in the right direction.

[peteski]

IIRC, I had come older Arnold  rapido (or was it Minitrix?) models with 1.2 motor shafts, so that is not  all that unusual.

[Chris333]

The Arnold S2 had some odd shaft size, plus springs for worms.

[u18b]

Finally Perfecting the Drive Train

I’ve worked with brass Shay’s for almost 30 years, and have been working intensely with them for well over a decade.

I have no doubt that these ran great when the recall happened.

But that was 30 years ago- and I can tell you from a lot of experience- the drive train of these locos runs from highly finicky to disastrous.  And the more I run mine, the more they fall into the latter category.

But I found a fix.   And if you own one of these version 2 Shays, you will WANT to do this.

First let’s review the problems.

Here is a photo of the original drive train (ignore all the colored arrows).

Here are the universal problem spots from right to left.



First- the stock Sagami can motor is not very good.   It’s weak, 3-pole, and loud.

Next- the rubber tubing coupling between the motor and the worm is horrible.   This may work on some locos- but not this one.  The main problem is the huge differential between the small motor shaft and the large adapter on the worm shaft.  That adapter is so large- the tubing cannot adequately grab the motor shaft.

The next problem is the worm bearings- they wear easily- and then wobble comes into play- and noise.

Then the worm shaft itself is a problem.  It’s made of a very soft steel and can wear terribly- adding to wobble- and noise.

Then there is the fatal flaw of the worm and the worm gear.  Both are made of brass and wear terribly.  But since the worm spins 18 times for every single gear turn, then what happens is the worm is eaten away.

And then there is the worm gear  (the gear with the screw in the middle).  When new- everything is fine.  But as that spinning gear wears around that screw, an eccentricity is created in the screw hole.   This then creates gear wobble- and noise.

This design is awful and I have spent 100s of hours trying to get Shays to be quiet.   I have succeeded in the past- but rarely.

The first seriously positive progress I made was when I came up with this configuration.



What you see is a fabulous coreless motor, and an original OMI bearing with original worm on the left and the drive train has been Beardenized- that is, the inner bearing has been removed and the wormshaft and the motor shaft have been coupled together.

This solves a LOT of noise issues- but does NOT solve two things:  a)  the excessive eating away of the worm,  b) nor the noisy worm gear with the screw going through it.

But now, with the wonderful suggestions of Chris and Max, I have arrived at what appears to be the fabulous solution.

Furthermore, this is something almost everyone can do if you own a 2nd version Shay.

I’ll explain it in the next post.