SP&S E7 #750 Completed Kitbash

[mmagliaro]

EDIT #2:
I finished the project.   New photos at the end of this thread.
END EDIT #2

EDIT:
Since I started putting some photos at the end of this showing the conversion to SP&S #750, I figured a new thread title would make more sense.
END EDIT:

Sooo... I seem to have landed a lucky E7 BLI shell.   What mechanism would folks suggest be
good to put under this.
I am aware of:

1. Kato E8/9
2. Broadway Limited E7
3. LifeLike E7

Bearing in mind that I will do body mount couplers on this, and will make whatever mounting I have to in order to
get them on the shell, what do you think of using a "B" mechanism if I can find one cheaper than an "A".

Oh... and if I would have to machine down the sides of a frame to make it fit, no problem.  Don't let that rule
out a mechanism.


Thanks for your opinions.

[peteski]

I would go for Kato - is there anything else that even comes close?  Especially since you will make it fit, no matter what is involved.  Kato A and B units use the same chassis.

[spookshow]

The BLI E7 shell is a good fit for a Kato E8/9 chassis. The window inserts are a bit of a sticking point, but I'm sure you can figure out a way around that.

Cheers,
-Mark

[altohorn25]

I would (and have) used the kato mechanism.

Nate

[mmagliaro]

Thanks all.  That's the way I was leaning.  I am glad to hear a few people have done it.
Not worried about the window inserts.  Those can be managed.

[mmagliaro]

I have successfully merged the Broadway shell to a Kato E8.  It took some doing, but it is running beautifully now.

The reason I bothered with this is that I scored one of the limited-run Lowell Smith SP&S E7 #750 shells for
a good price on eBay.  I'm very surprised that this shell ever got separated from its mechanism, but
lucky for me!

It requires grinding away all the protruding bulges along both sides of the E8 frame.  After that, the shell slips on nicely.




The nose insert needs to be hacked down as well.  I just filed and fitted until I got the shell to sit nice and level.






There were two issues that the Kato E8 needed help on.  First, I was surprised that it didn't pull better.
It weighs 128g, about the same as an old-school F unit, but it can't pull nearly as well.  It is probably because the weight is distributed over 6 wheels, so there is no heavy concentration on any single pair of wheels.

Anyway, I added traction tires, like so:




And Shazzam!  It pulls a ton!




You do have to be careful how you cut those tire grooves, and get them just right so that you don't lose good pickup contact from the other wheels.  My first attempt didn't cut quite deep enough, so the engine rocked a little on the center wheel and had lousy pickup.  But I remedied that by just chucking them back in the mill and cutting another .005".

------------
One other very important issue came up regarding pickup and tracking.   The wheelsets in these are quite
snugly held between those pickup strips in the truck frame sides.  The axle points ride in cone-shaped holes, like many well-designed trucks.  But there is ZERO side-to-side or up/down play in the axles.  This is very bad for going over even the slightest dip in the rails, or through a turnout where you get a little wheel drop at the frog.

Even worse, the wheels are narrow in gauge, so after you spread them to the correct width, they get even more rigid.   I disassembled the trucks, and used a #61 bit in a pin vise to drill the cone holes in each pickup plate a little deeper, thus allowing some play in the axles.  It works wonders.  The whole engine just plain ran smoother and could run slower.  And I got rid of some annoying stalling.  Any time it would round a curve, the engine would slightly lift up the 3 wheels in each truck on the inside of the curve,  just enough to lose contact.  Now that they
can float a little, it tracks much better.

You do have to be careful drilling into those cone holes.  If you drill through them, the truck is ruined.
I just spun the pin vise by hand and counted turns - 10 turns in each hole, reassemble, see how the axle play is.
Take them out, drill 10 more turns, and so on.  30 did the trick.

[peteski]

Interesting conversion Max.  Funny, looking at the BLI shell I see how heavy-handed the details look compared to Kato F and E units.

As far as axles being too tight, I would have simply pressed the half-axles a bit inwards.  To me that would be simpler and easier than deepening the bearing holes.



If you are worried about drilling through the bearing holes, you could get a 60 degeee countersink to deepen the hole. AFAIK, that is the same angle that the axle-points have.  I bought few of 1/8" shaft carbide 60, 82 and 90 degree countersinks.  They aren't very expensive and they come in very handy.

But installing a traction tires on a diesel loco (and on the middle axle)?  Shame on you!    Who do you think you are?  Hornby/Arnold? 

[nkalanaga]

Peteski:  Almost anyone else I'd agree, but if MAX wants traction tires, he must have a very good reason!  Let's just hope the manufacturers don't take it as an excuse to add them to everything, instead of putting enough weight in the models to start with.

Yes, I know you weren't serious,

[mmagliaro]

Heh... ya gotta do what ya gotta do, Peteski.  With 6 wheels on each side, I figured I could give one up and still
have reliable pickup, and I do.  Especially considering that the middle wheel in a 3-axle setup is usually the "laggard" that doesn't contact as much.

EDIT:
N Kalanaga:
My good reason was that the darn thing just can't pull well enough without them.
And it is already very heavy.
And there's nowhere to put anymore weight unless I start boring out cavities and replacing them with tungsten.
I thought about it, but the traction tire produces so much better results in this case because it's already
got plenty of weight.
The engine runs smooth as silk. 

I thought about pushing in the axles, but the wheels are pressed onto them very tightly.  It seemed easier to just twirl the old pin vise in the cups.  The shell doesn't look that bad to me.  And remember, all the grabirons, are missing, which will help a lot.  I have the E8 shell that came on this engine, and it doesn't look all that much better to me.

I really like the elegant design of the Kato E8 mechanism.  It just needed a little adjusting to make it really
sing.  Although holy cow, what is it with Kato and their slot-car gearing?  This thing can easily do 200+ mph.
I am thinking about getting an Atlas scale speed motor and dropping it in there.  It has the flywheels with the hex holes on the ends, so it should just about be a drop-in.  That would knock off some speed and increase
power.

If anyone has done this, let me know.

[Chris333]

I like that paint scheme.

[mmagliaro]

I like that paint scheme.

Me too!  If it were the later "broadstripe", I wouldn't have  done this.

[peteski]

Max - my comment about the TT was tongue-in-cheek (especially in light of the recent comments about TTs on the center axles of the Arnold's new 6-axle U-boat).  I thought the emoticons  made that clear. No need for explanations.

But OTOH, if the center wheel doesn't contribute much to the pickup (due to intermittent contact with the rail?) how do you explain that the contact with rail is positive enough for the traction tire to grab?  And if the tire grabs because it increased the diameter of the wheel, doesn't that lift the other 2 axles off the track giving them (and that truck)  less positive electrical contact?  I'm just thinking out loud here - just some theoretical musings. No need to address this. Like Nick said - you did what was needed and it exceeded the expectations.

Pushing the half axles is easy.  I just do it on a small arbor press. I I use piece of aluminum over the point so the steel press doesn't flatten it.  But deepening the cones works too.  The 0only thing that worries me that this made the metal even thinner in at the point where it will wear the most.  I've heard of those getting worn through in heavy use.

Kato locos are speed demons. They have been since their first loco: GP38-2. We all know and expect that. But to me they are still some of the best made and best running locos out there. Even with the high top speed, they have decent slow speed performance.   Actually it would be interesting just how much slower the Atlas motor retrofit would make that loco.

Personally I have a theory about Atlas slow speed motors and what they give up to slow them down, but I won't expand on it because it would raise too many eyebrows.    After all, I'm not a motor designer - just a hobbyist with strange ideas.

[mmagliaro]

I totally took your remarks as helpful and with a sense of humor, Peteski!  Not to worry.
About that tire, I suppose a more accurate statement is that in a 3 axle truck, I usually find
that two of the wheels make good contact most of the time and the other one doesn't.
I support all three could be perfectly aligned so they contact equally, but it doesn't seem likely.

With   my tire, the trick was to get it set just right so it makes some contact, but not enough
to lift the others off the rail.  The first time, I didn't  quite get it right.  It stuck out too much
and the other two rocked on it like a see-saw. The pickup was terrible and the engine sputtered
all over the place.  So I cut another .005" into the grooves and tried again, with much success.
It  could run around my entire layout at creep speed with narry a sputter or stall.

The "scale speed" motor would supposedly have more windings of thinner wire so it would turn slower
and produce more torque.

[Lemosteam]

Max, that is beautiful.

What was the resulting diameter under the traction tire, and the groove width that you settled on?  Also what brand traction tire did you you use?

[mmagliaro]

The metal wheels are 0.252" on the tread.  I cut them down to 0.238" 
Initially, I cut them down to 0.244, because the traction tire rubber measures about .010",
so I figured a groove just a little less deep than that would let them stick out just a hair
like I wanted.

But you sharp-eyed (and sharp-brained) Railwire-ians will note that cutting 0.252 down to
0.244 knocks .008 off the DIAMETER, which means the depth of the groove is only .004"...
whoops.
At 0.238, I have cut .014" off the diameter, so the groove depth is .007".
With a rubber tire that measures .010" thick, and allowing that when stretched around the wheel, it will
thin out a little more, .007 is just about perfect.

As to what brand of traction tire I used... I have no idea.  They came straight out of my miscellaneous
stash of traction tires.  The Kato Mikado is too large.  I tried those.   These come from some diesel,
but I have no idea which one.   If I had to guess, I think they are the smaller size ones that Bachmann
sells as separate parts on their website.  They sell two sizes, and these would be the smaller ones.

I cut the grooves with the same steel tool I made to cut the grooves in those steam loco driver tires
I made a few months ago (and no, I have not forgotten about those.  That project will return when
I finish some other things)