Lifelike/Walthers (LL) Berkshire tinkering

[strummer]

D*mn Max, you do such fine work...simply outstanding.

Mark in Oregon

[Chris333]

All these years I had a grooved driver sitting in a box and never thought to swap out the one in my running Berk just to see what it can do. Mine runs pretty good right now, but I think I hear slipping around curves.

[jdcolombo]

Hi Max.

The pickup issues you are having after the TT addition are similar to what I experience after using tape on the drivers.   The LL's power pickup from the engine alone is questionable, particularly if the #3 or #4 drivers aren't available for that chore.  The pickup issues with the tender likely aren't just the tender trucks, but also the wires that contact the "nubs" on the underside of the tender.   I've had to bend these way out to get sufficient contact force to get good conductivity through these wires to the engine frame.

I'm now starting to wonder if the Bachmann tender will fit the LL . . .

Are you using a lathe or a milling machine to cut the groove?  And what kind of tool is that (what you are using to cut).

John C.

[mmagliaro]

John,
That's a vertical milling machine.  The tool is a steel tool blank.  I just took it and used a Dremel with a diamond cutoff wheel to cut away some of the edge and shape it until I got a cutter bit that made a TT groove I was happy with.

In my SP&S 4-6-2 loco build thread, I showed making a tool like that for cutting domes.

I clamp the tool in a clamp bolted to the X-Y table under the mill.  I set the position of the cutter against the wheel totally by eye, and start cutting very slowly.  As it starts to cut some metal on the wheel, I can see right away if I've got the location right.  It's really not that hard to set it by eye.  Then I just keep advancing the handwheel to move the cutter deeper and deeper into the wheel as it cuts.  I stop every so often and check the diameter across the groove vs the diameter of the whole tread.  When I've taken about .014" off the diameter, I stop.

It's not ultra-precise in the world of machining.  But for things like this.
It got a lot easier when about 2 weeks ago, I discovered a loose bolt in the travel mechanism that controls my
X-Y table       Wow... things work a lot better when everything on the mill moves smooth and true
with no play!

Really, the way I'm using the mill is more like using a lathe standing on end. 

----------
Chris, no matter how much weight is piled onto this engine, I don't think it can ever approach the pull you can get with a traction tire.  Those drivers are very slippery.  My only knock *against* adding a traction tire is that there is definitely a little less super silky smooth motion through curves.  An engine with no rubber feet can really slide and glide through curves beautifully.  But it's a small performance hit, relatively speaking, especially compared to the pulling gains.

Oh, on those drawbar wires.  I hate hate HATE spring drawbar wires.    HATE THEM.
On my own Berk,  I have wires run through and soldered at both ends.   It means I can't separate the tender, but I gladly give up that convenience for having 100% perfect electrical conductivity between the engine and tender.
I get so fed up with bending and fussing with those springy wires.

But in general, a lot of people really want the tender to be able to separate, and this second Berk isn't my engine, so I am not going to solder it across.

[peteski]

Max, I have a lathe but I'm always afraid to chuck wheels by the small diameter back stub.  I'm afraid that making a much larger diameter surface will create enough torque on the chucked part to shear it off.  how much material do you remove in each pass? You must be going very slowly.  Maybe some day I'll grow enough ballz to machine grooves that way.

I also noticed that the tires are made of plated (gold colored) brass. I wonder if the plating makes them so slippery on the track?  I think Kato uses nickel-sliver or some brass alloy which is more silver in color.  They still use plating too, but it is probably different metal that the one used by LifeLike.

[mmagliaro]

Hi Peteski,

I used to worry that the moment the cutter touched that wheel, the whole thing would tear to pieces.  But as it turns out,
the metal these wheels is made from it pretty soft and very easily machinable.

Yes, there is a plating over brass (it looks like).   I'm sure that is partly responsible for how slippery they are.

As for my feed rate, I don't really know.  I can tell you that I'm running this at very low RPMs, maybe 250-300.
I put a drop of oil on the cutter, and I advance the handwheel until I just hear the metal start to scrape and see a little metal dust coming off.   On some metals, it peels off like a traditional lathe cut.  But on these, it just came off in piles of dust, almost the way it would if you were using a file on it.   I took that as a good sign that it was taking only a tiny
amount off at a time, which is good.

You also have to play games with how tight you can chuck that hub.  I'm sure if I overdid it, I would crush 3 lovely flat spots into the hub and it would wobble down the track like an egg.  I just do it by feel.  Once, it did lose its grip and spin a little in the chuck, but I just backed off right away, tighten the chuck another 1/8th of a turn on the key, and went at it again.

I don't know if it's always safe to do.   I've done only 2 Berk axles, and they both worked.
Sometimes, when I'm done, I "dress" the edges a little running a really fine file on the inside walls of the groove for a bit as it spins, just to get rid of any sharp edge that would be very unfriendly to a rubber tire when trying to stretch it over the edge.

[peteski]

Thanks Max.  One of these days I might finally break down and try making a groove that way.  But I'll probably try this on a spare driver set (or a loco where I can still purchase spare parts). 

[Chris333]

I just dug out my old project. The TT groove is on the 3rd driver. Do you think that will give me any problems?

[mmagliaro]

I just dug out my old project. The TT groove is on the 3rd driver. Do you think that will give me any problems?

I don't know, Chris.  I have a theory that the engine can rock over the 3rd driver like a fulcrum if the traction tire is there and there is a lot of pulling from a heavy train on the back, like a see-saw.   But I don't really have any proof of this theory.

It wouldn't be much.  When you think about it, the rubber tire should only be sticking out by .002" or .003".  But if the center point of a seesaw is .002" in the air, how high up do the front drivers go when there is heavy pulling on the rear?    .005" ?
That could be enough to lift the front flanges up and out of the rails on uneven track or curves.  After all, the flanges are only .024" deep or so.  So .005" is a lot.   I would not fret about it unless you see it lift up.  Run it with 30 cars behind it around some curves and watch the front wheels.

I'd say that if you have weight in the front, and your improved drawbar, it should work fine.  Without those two things, it's hard to know.

--- Max

[Chris333]

Since my last post I have pulled the 3rd driver out of my working Berk and put in the TT driver. And yes there was see-sawing. Also the gear did not line up with the rest of the locomotive. The hole in the side rod didn't quite line up and when I skipped to the next tooth on the gear it was off in the other direction. Like they built the drivers as a set? 

But I wedged in the crank and gave it a lap pulling about 40 cars. It walked like a duck due to the tight rods, but it pulled the train with ease. Could have pulled more, but I didn't have that many cars out. I only gave it a few laps and then popped the original driver back in it kill the waddle.

The TT driver back in my project frame with the all drivers installed didn't see-saw, but I could have shimmed them up that way a while back, who knows.

But yeah the TT works!

[mmagliaro]

Chris,
The 3rd and 4th drivers are gears and pinned.  The front two are pinned only.
Try taking the crankpins out of #4 with your slightly-off driver in the #3 position.
As long as #3 is quartered okay, it should drive #1 and #2 around just fine, and #4 should run on the gear alone.

If that works, you can either just let the rod run in front of #4 with a phony crankpin head on it (like the Kato Mikado), or you can egg-shape the hole on #4 so the rod won't bind on there, but will just ride around for show in front of #4.

I think egg-shaping the hole would be better.  The rod won't wobble in and out and look as funny that way.

[sizemore]

With the Kato tires on this, the engine's pulling soared.  It could only pull 8 cars up the hill before.  Now it is pulling 40 and that's not the limit yet.  HOWEVER, the front driver is starting to lift.  It's not enough to derail on curves yet, but all that pull on the tail is starting to lift it up.  I do not have any extra weight inside the body on this one.  My other one had all the weight I could pack up in the big rectangular dome and over the worm cavity inside.   Based on the owner's wishes with this one, I may not crack open the shell and go that far.  It can pull between 30-40 cars even on grades with no trouble, and that's more than adequate.

And another believer in the Wallyworld Berk with traction tire, welcome to the club.

The S.