Best Of Spokane, Portland and Seattle (SP&S) 0-6-0 Project

[jdcolombo]

Never in a million years would I have either the patience or talent to accomplish this.

Bravo, Max. 

John C.

[peteski]

As for the coupler itself, all I can say is it's a Bowser Buckler Z scale coupler, so it's already the smallest possible coupler I am aware of that works, so there's not much I can do about  it.  N Scale couplers are unfortunately oversized, even when the smallest Z coupler is used.

Then there is the MTL true-scale coupler, but it is not automatic and doesn't mate with N scale couplers.

[robert3985]

Geez Max!  Quite the inspiration.  Every time I look at this thread I learn something new! Just EXCELLENT!!

...About the front coupler... I do plan to wrap the exposed coupler box in thin brass to form a proper exposed box.  The box extends by the proper amount, believe it or not.  Thus has been been mentioned earlier in this thread.
As for the coupler itself, all I can say is it's a Bowser Buckler Z scale coupler, so it's already the smallest possible coupler I am aware of that works, so there's not much I can do about  it.  N Scale couplers are unfortunately oversized, even when the smallest Z coupler is used.

I've posted this before, but this photo gives a side-by-side comparison of the sizes of a scale, dummy coupler and the MTL 905 Z-scale coupler. 

Photo (1) - MTL 905 on tender of Key USRA UP-ized Mikado (MacArthur) coupled to scale sized pilot dummy coupler on another one for double heading:


Photo (2) - Scale-sized dummy coupler and MTL 905 coupled up:


Although the MTL 905's don't look much like prototype couplers, their size is pretty close in most dimensions to a prototype, scaled-down coupler. 

Here are the measurements:

Photo (3) - Measurements I took off a prototype AAR coupler on the front of the 833 (UP FEF-2) with N-scale info in parentheses:


If you need a fully functioning coupler on both ends of your switcher, to switch...I'd stick with the MTL 905's since they're fully compatible with most N-scale sized knuckle couplers, and can be easily uncoupled with a martini toothpick, RIX uncoupler tool or something similar.

Although I think the MTL True Scale couplers are better looking than either the Bowser Bucklers or the MTL 905's, unless your entire roster of cars and engines are equipped with them (properly modified), I'd stick with the function of the MTL 905's and live with their looks...which truthfully isn't too much of a concession for me.

Cheerio!
Bob Gilmore

[mmagliaro]

Thanks for the coupler info, Bob (and your compliments  )
To my eye, the Bowser coupler appears smaller, even though it may not actually be.  While it doesn't couple to an MTL coupler as easily as a true MTL (it needs a bit more off a "slam" ha ha), and even though I probably will not do much actual operations with this engine, I wanted it to be something that does work, not a static dummy.  The Bowser is the compromise, of all the compromises we have available, that I prefer.

[mmagliaro]

Folks, here's some video of it running with the valve gear in action!

[narrowminded]

That's being pretty sweet, Max!

[wazzou]

Looks good Max.  Do you know what the source of the lift is during motion on the engineer's side?

[mmagliaro]

Looks good Max.  Do you know what the source of the lift is during motion on the engineer's side?

Heh,  you boys don't miss a trick!  It is most likely a slight quartering error that causes that. 
The engine can run really nice down to 1 mph, so it has to be a painfully slight amount of error.
I have spent a good amount of time diagnosing it, and I think that's what it is.  But at this point,
there is no way I'm going to pull those drivers apart to attempt a correction, especially when it
runs so well otherwise.   

[Lemosteam]

Are you sure Max?  I did not see any evidence of lift in the other video.

[mmagliaro]

Are you sure Max?  I did not see any evidence of lift in the other video.

The last video had the brass temporary rods on there.  And I am pretty sure that even though I used those as drill-through templates to make the real ones (more than once), there must be a hair difference somewhere in the rod holes
that made them a little off.  The tolerances on this thing are painfully close.  Just a few thousandths off
on a rod hole would be enough.   I may try one more trick up my sleeve to see if this can be eliminated.  But if that doesn't work, I think I have to live with it.   Remember, you're looking at this ultra-magnified.  It doesn't show that much when it is just running down the track.

If you watch very closely, in slow motion, just as that "lift" moment occurs, you can see that the forward driver is not rotated around quite enough.  I think the rod hole for the forward driver on the opposite side is just a little "short", so it hasn't pushed the wheel around quite to where it needs to be at that spot in the rotation.  I may be able to shim that rod hole to shift it slightly foward by .002" or so to correct this.

[Lemosteam]

That is exacly what I was thinking Max.  The new rods are slightly different.

[Centercab]

I am way late to the party, but that thing is pretty sweet.  Nice work!

Chuck

[mmagliaro]

That is exacly what I was thinking Max.  The new rods are slightly different.

Yeah, but realize that "different" on this thing really is a matter of .002" or .003" at most !    I made a number of sets of rods before I got two that worked well, and that was even using the original brass ones as a drilling guide.    That wheel probably just needs a breath of air on it at the right moment to get around a little more to prevent this problem.  LOL!

I'll see what I can do.  I just know that at present, I can run this thing at sub-1 mph speeds, so the error is painfully small, and it may not be fixable.

[chessie system fan]

Excellent!

Any idea how many cars it can pull yet?

[mmagliaro]

Excellent!

Any idea how many cars it can pull yet?

About 16 on level track.  That will be perfectly acceptable to me for a small switcher.  But I have done nothing to try to boost its pulling power.   There's a lot of unused space in the cab, right over the traction tire, so when the time comes, I will try adding more there.   And there is a lot of metal that has yet to be added to the body - things like brass domes, walkways, air tanks, etc.  So it is going to gain weight as I go.  I'm not going to make the body removal or servicing harder by trying to bulk this thing up.
On my road engines, like the NP W-5 2-8-2, I wanted muscle.  But for a small switcher, 16 cars is plenty.