Author Topic: Mystery Engine build???  (Read 2260 times)

GPdemayo

  • Modeler's Hero 500+ Posts
  • *****
  • Posts: 3202
  • Karma: +5/-0
    • View Profile
Re: Mystery Engine build???
« Reply #45 on: September 10, 2017, 08:52:30 AM »
Neat..... 8)
Gregory P. DeMayo
General Construction Superintendent Emeritus
St. Louis & Denver Railroad
Longwood, FL

Donato

  • Modeler's Hero 500+ Posts
  • *****
  • Posts: 1328
  • Karma: +0/-0
    • View Profile
Re: Mystery Engine build???
« Reply #46 on: September 11, 2017, 03:35:30 PM »
What he said...!!
Thanks,
Donato

Biding my time till I can start my layout and build nice stuff like all you folks .... (said with envy). :-)

tct855

  • Modeler's Hero 500+ Posts
  • *****
  • Posts: 716
  • Karma: +0/-0
    • View Profile
Re: Mystery Engine build???
« Reply #47 on: September 11, 2017, 09:15:51 PM »
Thanks for the neat comments, ;D
            Here are the final pics of the Gem Models 4-4-0 DC rebuilt.  Custom Highball Graphics, N.W.S.L. custom motor/gearbox, 4 continuous working LED markers, continuous working LED Headlight, Backhead & details, all wheel pickups, full articulated tender trucks, cab chairs w/engineer/fireman, working bell w/wire cord, removable coal load & track power tender wire connectors added.  (excuse the dust on model) (I forgot to brush before pics). On behalf of the band and myself, Hope we passed the audition!  Well that's my story and I'm stickin' to it.   Thanx Thom... P.S. For me, this was a tough tough build, but very rewarding now that it's completed. ha. Now on to the second custom 4-4-0 build.
« Last Edit: September 11, 2017, 09:25:54 PM by tct855 »

jbvb

  • Senior Poster 250+
  • ****
  • Posts: 453
  • Karma: +0/-0
  • Modeling the B&M's Eastern Route in HO 1950 - 1965
    • View Profile
    • New England RR History & Modeling Info
Re: Mystery Engine build???
« Reply #48 on: September 11, 2017, 11:31:38 PM »
Interesting, particularly the drive. I've got a B&M A-41f 4-4-0 imported by PFM long ago, in pieces after being stripped.  The original was bad enough that MR knocked it in Trade Topics! When layout work eases off a bit, I need to decide which issues I'll fix and which I'll live with.  If I can't make it haul two Ambroid cars up a 1% grade it's doomed to be a roundhouse queen.
James

tct855

  • Modeler's Hero 500+ Posts
  • *****
  • Posts: 716
  • Karma: +0/-0
    • View Profile
Re: Mystery Engine build???
« Reply #49 on: September 11, 2017, 11:57:45 PM »
James,
          I feel your pain on your PFM 4-4-0.  I have an old one also.  On mine I noticed the cylinder saddle is way undersized, and the frame is bent upwards so it would actually meet the boiler.  The tender's trucks have journal boxes that stick out little beyond the side of the tender (not perfectly to scale).

I'll need to change both motor/gearbox setup.  Other than the usual things.  It's got nice detailing throughout.  I won't get to mine for some time.  Let me know how your rebuild goes. 

The motor gearbox design is the only way I've been able to repower all the 0-4-0t's, 4-4-0's, 2-6-0's, 4-6-0's etc. Derrell at N.W.S.L. custom builds each one ordered, but it's what one needs to fit in those little tight engines and still be able to keep the backhead. ha. Thanx Thom...

bparrish

  • Modeler's Hero 500+ Posts
  • *****
  • Posts: 1787
  • Karma: +3/-0
    • View Profile
Re: Mystery Engine build???
« Reply #50 on: September 12, 2017, 01:49:41 AM »
Thom....

Your photos above with the motor shaft pressed onto the worm gear is genius.

That is not hard to do ..........  I need to remember that.  It's all about setting up bushings that will get you from the motor shaft to the worm.  Not that complicated.

I'm only upset because I didn't think of it.

thanx
Bob
All it takes to start and insane asylum is a big room and the right kind of people.

7thStreetShops

  • Early Member
  • *
  • Posts: 27
  • Karma: +0/-0
    • View Profile
Re: Mystery Engine build???
« Reply #51 on: September 12, 2017, 12:41:33 PM »
Thom, Wow! that turned out "sweet", my friend! Beautiful Job! Got a video cam? I'd love to see it running.

I think we modelers sometimes forget that the Laws of physics are oblivious of scale. What I mean by that; a 1/16" error in 1:1 scale might be acceptable but as things get smaller, say down to 1/87 scale 1/16th becomes .0007". Can you work to those tolerances? I can't. My lathe and mill goes down to .001" and I have to guess at what is between each tick mark. There are computer controlled machines that can achieve these kinds of tolerances, but I can't afford those. And when you are talking about degrees and radial measurements - as in quartering drivers - the issue becomes even more acute. One degree in 1/87th scale becomes half a flea whisker on a 57" driver. I can't see a whole whiskery let alone a half.

To compensate, model manufacturers add slop to other parts of a mechanism. Where the prototype might have 1/16 play in the side rod pin holes HO models often have an inch (scale) of play to compensate for the margin of error in the driver quartering. And some people, in frustration (raises hand), finally resort to making that margin even larger - even tho they adamantly oppose touching the pinholes in side rods (keep in mind driver quartering is only ONE reason why driver quartering is incorrigible).

Uh- unless you know what you are doing - or unless the holes are (wore) elliptical - DON'T DO THAT!

When you are talking about motors and gearboxes the issue is still physics and tolerances. You have about 2 to 4 thousandths of an inch of run out between 2 Mod .3 gears and about 1/2 degree off of wobble before you start getting the dreaded wahh-wahhh-wahhhhh and an inconsistent rotation of the assembly! Antecedent to a Swiss watch mechanism.

A long motor shaft and gear box shaft are best for several reasons but primarily because it is a lot easier to place each on the same exact axis. But when you cut that down to just enough length for the bearings and worm - YIKES! The hole in the worm just about has to be an exact fit to the shaft diameter. ANY variation in the shaft axis and the centerline of the worm and the skewing causes the worm and worm gear to mesh inconsistently. ...wahh-wahhh-wahhhhh...

In our case the worms were custom drilled to the closest match we could get to the shaft diameters and in some cases we have to use the worm as a friction coupler of 2 shafts because the newest motors do not have shafts long enough to hold a bearing on the opposite side of the worm.

Uh... did I say Yikes! ?

BTW you better have an idler made of plastic in the gearbox so your DCC decoder doesn't have a direct electrical path from the motor control circuit to the track.

I don't know most modelers but the indicators I see on a regular basis is that changing gear boxes in a steam locomotive is a complete mystery to them... so they model diseas-els. Nothing wrong with that. Flanges and rail. That's what it's allllll about; flanges and rails. 

Derrell

tct855

  • Modeler's Hero 500+ Posts
  • *****
  • Posts: 716
  • Karma: +0/-0
    • View Profile
Re: Mystery Engine build???
« Reply #52 on: September 12, 2017, 04:19:29 PM »
Bob,
       Thank's for the compliment.  Also what Derrell is saying (partly) is when I use to have the old 16x30 can motors they had bigger double shafts.  So press fitting a worm and bearing right up next to the motor was doable 7 out of 10 times for me.  (yup i bent a few shafts).

All done on that side but the next side would be more exacting due to the motor leads were right there!

Now since the new motors came out.  They are even more difficult due to the shaft is even smaller (easier to bend) and shorter which means the other side of the gear box bearing is only receiving a tip of the shaft when (if lucky to press on without bending) on.

Bob you are a modeler of many talents.  You might be able to do it.  Me?  No way!  That's why I buy lottery tickets, beer, and hookers for Derrell.  So he'll do up a dozen or so at a wack.  Did I mention, he hates me.   ;D  Thanx Thom...

P.S. Derrell yes on the video, when I finish off the second one. Then I'll do together.  T...


BTW, the winner of the bragging rights goes to the first replier Dr. Jeff-Zephyrus52246  He's the brainiac.  Congrates Jeff.   Here's your sign!
« Last Edit: September 13, 2017, 03:35:28 PM by tct855 »

bparrish

  • Modeler's Hero 500+ Posts
  • *****
  • Posts: 1787
  • Karma: +3/-0
    • View Profile
Re: Mystery Engine build???
« Reply #53 on: September 12, 2017, 04:27:17 PM »
Derrell..

Thanx for the information.  I couldn't do some of the trolley and small steam loco's in HO without the consistency of manufacturing from NWSL.  They are great.

Your remarks about pin holes in side rods are spot on..........  I tend to make my frame dimensions so tight that it demands really accurate side rods.  I think some of the import manufacturers have so much slop that you can assemble it from across the room.......... sorta like throwing darts.

I am aware that the smaller the gauge the more critical the fit really is.   When I built the Falk loco (see thread elsewhere on this forum) some years ago, G scale made it seemed like it was much more forgiving of quartering.  I had built a quartering jig out of four steel carpenter squares, sandwiched together.  It worked and I was able to run really tight pin holes. 

Again......thanx
Bob
All it takes to start and insane asylum is a big room and the right kind of people.

bparrish

  • Modeler's Hero 500+ Posts
  • *****
  • Posts: 1787
  • Karma: +3/-0
    • View Profile
Re: Mystery Engine build???
« Reply #54 on: September 12, 2017, 06:23:35 PM »
Thom...

I need to know how you striped the wheels.

thanx
Bob
All it takes to start and insane asylum is a big room and the right kind of people.

tct855

  • Modeler's Hero 500+ Posts
  • *****
  • Posts: 716
  • Karma: +0/-0
    • View Profile
Re: Mystery Engine build???
« Reply #55 on: September 12, 2017, 08:29:54 PM »
Bob,
      Page 1 about midway down.


Hey modelers,
       
           Okay, so I guess since no one attempted to answer the question on how I painted the stripes on each spoke of the wheels with an airbrush and no paint brush and no masking.  That must  mean you modeling Einstein's already knew the answer.

 I did another engine many years ago on the old forum. http://www.kitforums.com/viewtopic.php?f=15&t=15986



This model is for the same customer as the others.  The process is the same.  I hand cleaned & filed each spoke as close to the center as I could get.  Then sprayed the front with etching primer first, then spray the accent color on. Baked dry, then sprayed on the black from the rear of the wheel spraying left/right/up/down on each spoke.  Taking my time is key.  Now you know the rest of the story!  Thanx Thom... The trucks are next!



Hope this helps!  Thanx Thom...

7thStreetShops

  • Early Member
  • *
  • Posts: 27
  • Karma: +0/-0
    • View Profile
Re: Mystery Engine build???
« Reply #56 on: September 13, 2017, 12:11:59 PM »
More about the Wah-wahh-wahhhh effect. Experience Tells me that any variation from "perfect" can cause a faulty mechanism (perfect being both the theoretical and practical operative here). Variation from perfect; meaning precisely aligned shafts, true perpendicular in all cases necessary, and exact matches between quartering degree AND the equation of C-C of axles to C-C of side rod pin holes in all cases.

We depend upon the maker of the engine to ensure that the C-C equation as well as the matched quartering are dead on - and I mean DEAD on! There is very, very little margin of error especially in the smaller scales. We also, to a lesser degree, depend on them to place the gearbox and motor properly. But since these are relatively easy to replace we can take over that responsibility when they did a poor job (by faulty practices such as floating motor shafts with open worm axle gear "non-box" gear arrangements). It is still a precision job, nevertheless, so knowing a few principles helps us to attain that.

Since I've already discussed to some degree those principles I'll go on to my point.

The Wahhh-wahhhh-waarrrgh effect (hereafter "www" since it's a pain to get all those "h"s right) is simply a function of the variation of friction during the rotation of any of the several wheels (either gears or divers) and their relationship to the provided power or torque involved. A small motor will be more effected by slight variations in friction than a larger motor. The obvious get-away-with-it answer would seem to be a bigger motor (and making sure like materials such as brass against brass do not occur). AND liberal amounts of lubricant.

However the correct fix is to find and mitigate the friction; the consideration of the size of the motor should be secondary to removing any variations in friction. A big motor will still be effected by the variation but as I've described elsewhere the results of a big motor just bullying the www can wind up with stripped gears or gears worn so badly they make it impossible to fine tune the running into "perfect".

If you decide to replace a motor and gearbox (what I call the power train) on a steam loco make it your priority to insure there is as little friction, and especially friction variation, as possible. When you assemble a gearbox it should first make a single rotation around the shaft (holding the shaft and turning the gearbox) to assert that the single lead worm is good (2 rotations for a double lead worm), then, connect a power source to the shaft, assert that there isn't any variation thru the entire rotation of the worm gear (number of revolutions equal to the number of teeth) and then with the gearbox mounted to the axle that there isn't any www thru the entire rotation of the axle gear. Doing this with little or no lubrication to the gearbox is more assuring than soaking the gearbox with oil - it is easier to detect variations by feeling as well as observation. Even a small amount of consistent friction is better than www.

Gear boxes and power trains do tend to get better if the friction is consistent and of a reasonably small degree. Even variable friction will tend to lessen with run in time. But you can never "ware in" bad gear relationships. They will ware each other out!

If you find a problem with one of the wheels it is easiest, and frankly the only solution in most cases, to replace that wheel. However you may find that replacing a wheel, such as the idler gear makes no difference. Don't be afraid to "correct" the bearing; parts are not really that expensive in contrast to a poor job driving you nuts for years of poor operation.

If you install a perfectly running gear box into a bare bones frame and then find that it doesn't run perfectly when you install the rest of the power train and or frame mechanism you can at least recognize that any problems are in the motor or completed mechanism. The mechanism of the frame (valve gear main rods cross heads etc.) OR motor mounting are then suspect so leave the gear box alone and move on to mitigating any further causes of friction variation. With mechanisms every single animated point or component is suspect. No matter how complex look at EVERYTHING. If the motor appears to be the problem and you know it's a good motor look very critically at the shaft alignment to the gearbox shaft.

Enough said.


bparrish

  • Modeler's Hero 500+ Posts
  • *****
  • Posts: 1787
  • Karma: +3/-0
    • View Profile
Re: Mystery Engine build???
« Reply #57 on: September 13, 2017, 02:52:45 PM »
Derrell...

I read all of Mel Thornberg's stories in MR about building a locomotive on your kitchen table with simple tools.  That worked then because we modeled on the premise that if it moved it was OK.  We have much higher demands today.

In all of his stories he never said how to calculate the pin holes on the rods. I think he assumed something that I was slow in coming to.  Centers are centers ! ! !

Some years later I came with a simple measurement to solve this.  Measuring by holding a caliper over what looked like the center of a notch in the frame is just not accurate enough.  With a vernier caliper, measure the overall space between the axle notches, far side to far side.  Then measure an axle and subtract the diameter of one axle.  That will be the center of the axles on the frame and the length of the side rod C to C.

Again.. thanx for you information.

see ya
Bob
All it takes to start and insane asylum is a big room and the right kind of people.

tct855

  • Modeler's Hero 500+ Posts
  • *****
  • Posts: 716
  • Karma: +0/-0
    • View Profile
Re: Mystery Engine build???
« Reply #58 on: September 14, 2017, 09:50:03 AM »
Just as an FYI:

Derrell now uses on the newer (smaller) motor shaft loctite to secure the (slightly larger) worm on the shaft.  Which is the best method to press fitting the motor and gearbox together.  T...

Have you seen the new Loctite Train commercial?


7thStreetShops

  • Early Member
  • *
  • Posts: 27
  • Karma: +0/-0
    • View Profile
Re: Mystery Engine build???
« Reply #59 on: September 14, 2017, 02:52:37 PM »
Bob,

most modeling builders emphasize the practice of drilling all the plates of the Frame and Side rods as one soldered together assembly and then building the frame on a squaring assembly. Watch British modelers for best examples.

Replacing worn out side rods or rods wrong to begin with is very intense as their is no margin for error. Your description is pretty much what must be done and even then you will likely have to put more slop in the pin holes.

Thom, Locktite - WwwwWWWOOOWWWwwww!

NWSL is a Locktite Dealer.

 

SimplePortal 2.3.5 © 2008-2012, SimplePortal