Author Topic: Kato Mikado weight info and ideas  (Read 4777 times)

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mmagliaro

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Kato Mikado weight info and ideas
« on: April 21, 2014, 12:49:05 PM »
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I've been messing around with a Kato Mikado lately, getting it ready for the next engine project.
While handling the parts, I had two of the molded weights in front of me (the one that sits on top of the engine mechanism and is molded to conform to the underside of the boiler).
One looked darker and felt heavier, so I weighed them.

Sure enough, one was 10.1g and the other was 12.1g.  I can only surmise that over the years, Kato removed more lead from the mix, or removed it all, and the lighter one is from a newer generation of the engine.

But the really interesting thing is that from a thin lead sheet (1/32" thick, so it's very easy to cut and bend), I could easily
fold up a strip that would fit in place of the original, and it was 20g.  I didn't even try to shape it to add all I could to conform to the curved boiler.  I'm sure I could get up to 25g if I did.

Has anyone here created a custom weight to replace the original?  It seems like such an easy way to add 10-15g right over the drivers.   If I stacked up tungsten bits in there, I might be able to get 40g instead of 25.
If you are one who has put a decoder there in place of the weight, little tungsten disks could probably at least get you
your 12g original weight back.




Chris333

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Re: Kato Mikado weight info and ideas
« Reply #1 on: April 21, 2014, 01:46:16 PM »
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I have stacked sheet lead before, but I wonder if a bunch of 1/16" tungsten rods would fit  :D

mmagliaro

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Re: Kato Mikado weight info and ideas
« Reply #2 on: April 21, 2014, 01:52:21 PM »
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I have stacked sheet lead before, but I wonder if a bunch of 1/16" tungsten rods would fit  :D

Chris, I was hoping you would chime in here.   Are you able to get tungsten rod that thin?  Can you post a source?
I only have the flat plates, cubes, disks, and powder from the Pinewood Derby places.
Hmmmm... the plates....

People have become accustomed to just dropping the traction tire driver into the Mikado, so they probably
never think about the weight.  But the engine runs better with that weight in there, and not just because of pickup
and traction.   It is too heavily out of balance toward the rear without it. 

I've been testing and watching one run for a couple of weeks,
so maybe I'm now hyper sensitive to little changes in how it runs.  (And of course, mine doesn't have the original
motor in it anymore, so I'm looking for even more subtle changes in behavior  :)  )

I am going to end up with a GHQ boiler on there, so this probably won't matter to this particular engine because I'll
have plenty of weight.   But for a stock Mikado, adding 20-40g of weight  would make quite a difference.


Lemosteam

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Re: Kato Mikado weight info and ideas
« Reply #3 on: April 21, 2014, 02:08:22 PM »
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Max,
You could get some children's modeling clay, take a chunk and stick it to a heat resistant surface.  Push the original mike wieght into the clay, flat side up, until the flat surface is flush with the clay.  carefully extract the original weight so as not to distort the mold and there you have it- a one-off mold that can handle at least one 600 degree lead pour.  I use a mapp gas torch to melt the lead in a stainless spoon (ladle). Of course use proper precautions.  After it cools, remove the clay from the lead.  you may have to file or sand the flat surface to be the same as the Kato part.

It may help to put some air escape tunnels in to the sides usign a straight piece of wire.  You'll get less air bubbles.  That's how I formed the tank on my B8a around the metal B6 boiler shell.

Chris333

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Re: Kato Mikado weight info and ideas
« Reply #4 on: April 21, 2014, 02:13:21 PM »
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It's been a while since I played with a Mikado, BT (Before Tungsten)

Although I don't know how they would fit in the Mikado I've used 1/16" rods in this Nn3 boiler:


One day I will build another Mike so I look forward to what you find.

mmagliaro

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Re: Kato Mikado weight info and ideas
« Reply #5 on: April 21, 2014, 04:44:34 PM »
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John,
I was thinking exactly something like that:  make some sort of mold, press the Kato weight into it, then place bits of lead sheet in
there and melt them by hitting them with a pipe soldering torch until they liquify.
I was wondering what to make the mold out of.

How about just some simple portland cement?   Couldn't I press the Kato weight into that, let it harden, and then it
shouldn't be too hard to just whack one end of the weight with a chisel to make it pop out of there.

Now, I could place pieces of lead in there, and keep torching them until the mold is full of liquid lead, and then let it
cool.

Would that work?

//////////
I hand-formed a weight by just using the tungsten plates I have that would fit, plus cutting strips of 1/32" lead sheet to fit, stacking it all up and glueing it together.  I got about a 21g weight (still a lot better than 10 or 12!)




Lemosteam

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Re: Kato Mikado weight info and ideas
« Reply #6 on: April 21, 2014, 05:35:00 PM »
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I was successful making several castings using your favorite epoxy, JB Weld mixed with craft sand. But I had to make a ex pattern first.  Seriously. The clay will work really well.


Really though all you need is an old spoon or stainless measuring cup and a pair of vise grips.  I like to let the surface flash before I pour.

Mark W

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Re: Kato Mikado weight info and ideas
« Reply #7 on: April 21, 2014, 05:37:58 PM »
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You can also get Tungsten in putty form.  It might not be as dense, but you'll make up for that by being able to squeezing it into the entire void.  I used the t-putty on my DCC Gear-reduced Mogul.  So easy, I won't bother with anything else in the future. 
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strummer

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Re: Kato Mikado weight info and ideas
« Reply #8 on: April 21, 2014, 06:17:39 PM »
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I am going to end up with a GHQ boiler on there, so this probably won't matter to this particular engine because I'll
have plenty of weight. 

So...I take it we'll be seeing an NP Mike come out of your shop in the not too distant future?

Mark in Oregon

glakedylan

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Re: Kato Mikado weight info and ideas
« Reply #9 on: April 21, 2014, 06:34:27 PM »
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not attempt to side track the thread....but it seems like a place to get the need information:
quick question--to reduce gearing in steam locomotive, or any locomotive (I suppose) does one increase the number of teeth/gear, or reduce the number of teeth / gear...and it is the gear of the axles as worm gears are standard in their gearing?
thanks for any help!
sincerely
Gary
"...that each may live for all,
and all may care for each..."


mmagliaro

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Re: Kato Mikado weight info and ideas
« Reply #11 on: April 21, 2014, 08:37:16 PM »
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not attempt to side track the thread....but it seems like a place to get the need information:
quick question--to reduce gearing in steam locomotive, or any locomotive (I suppose) does one increase the number of teeth/gear, or reduce the number of teeth / gear...and it is the gear of the axles as worm gears are standard in their gearing?
thanks for any help!
sincerely
Gary

There are some common things across many engines, like the bore size and gear ratio, but in general,
gear changing is a can of worms.  Some things fit other engines, and some don't, and there is no
"standard" for any of it.
While there are some gears that are common across some engines (for example, a lot of Kato diesels have very similar sized gears in them), there are no guarantees, especially when it comes to steam.   The worm and worm gear on a Trix K4, for example, isn't the same as the worm in a Mikado or a Spectrum 2-8-0, and so on.

Second, to reduce the gearing, you need to either increase the diameter of one of the gears, or increase the number of teeth.
(At some points in the geartrain, like on the small side of a double gear that goes to the driver gears, you could
actually reduce the size of that small side, but it would be almost impossible because the diameter is already
very small).
The idea is that you want the worm to have to spin around more times to get that other gear to go around ONCE.
So that ends up meaning that the motor has to spin more times to get one revolution of the gear it is mated to, and thus, ultimately, the wheels will turn slower for a given speed of the motor.

It is not always easy to do either (increase the diameter or the number of teeth). In fact, it's darn hard in most cases.
The tricky thing is that if you change the worm and its mating gear, now you have to change the idler that mates with that, and then you have to change all the driver gears.  Finding those, even by measuring and calling NWSL, is not easy,
and the actual work of pressing gears off axles and getting all the bores and positions right is also not easy.

My preferred method is to forget trying to change gears, and instead, use a motor with an additional gearhead to
achive more reduction before you even get to the worm.   The Faulhaber or Maxon motors I like to use can be fitted
with in-line 4:1 gearheads.  So now you get a 4x reduction just by changing the motor. 

That comes with its own problems.
Sometimes it's not easy to make the motor fit.  Sometimes the output shaft isn't 1.5mm, so you have to either
grind down the shaft or bore out the worm to fit it on.  But all in all, the results are terrific.
The other big benefit is that the Faulhabers and Maxons generally have a lot more power and torque than
a conventional motor.  There are exceptions, meaning there are some weak coreless motors out there,
but the serious ones from those two brands are usually brutes.  And of course, they ain't cheap.  Retail prices
are $75 and up, PLUS the gearhead, which often doubles that number.  But you can get a much better deal
if you go to motorman (www.micro-loco-motion.com, or look for his motors on ebay).

I bet that's more than you wanted me to blather on about.   ;)

////////////////////////////////////////////

Chris,
Thanks.  Yes, I see rods and pieces on eBay.  I think I would like to get my hands on some really thin tungsten
sheet (like .010") so it can actually be cut without too much agony, and so that thin sheets can be stacked and otherwise placed inside boilers to add weight.    It's expensive on-line (about $50 for a 6x6" sheet that is .012" thick).
There seems to be some leaking out of Russia and the Ukraine on eBay.  Maybe...

Mark:
Yes, I'm pondering an NP 2-8-2, but I want to work out the details of the chassis and motor before I worry about
the cosmetics.
At present, I have it remotored with a Maxon 1024, and NO gearhead.  It runs great, although still way too fast.
I may just put a dropping resistor in there and let it be.  The current drain is so low that a small resistor will work fine.
It's hard to beat a 1024.. that's a very long coreless and it has a backshaft so I was able to put a huge 12mm diesel flywheel on its tail.  Plus, for a long time, I've wanted to see what I could do with a powerful coreless and no gearhead, just to see if they've really got the goods without one.

« Last Edit: April 21, 2014, 08:45:57 PM by mmagliaro »

Ike the BN Freak

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Re: Kato Mikado weight info and ideas
« Reply #12 on: April 21, 2014, 11:26:41 PM »
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You can also get Tungsten in putty form.  It might not be as dense, but you'll make up for that by being able to squeezing it into the entire void.

I've heard of making your own T-putty using white glue mixed with tungsten powder.

Get the powder from golf supply places, guess its used in clubs, for added weight.

Chris333

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« Last Edit: April 22, 2014, 05:48:18 AM by Chris333 »

mmagliaro

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Re: Kato Mikado weight info and ideas
« Reply #14 on: April 22, 2014, 07:15:15 PM »
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Correct, Chris.
It is quite impossible to fill a void with tungsten powder, glue, putty, or any of these other miracle tungsten
combinations, and get it to be any better than lead, and in most cases, it will be worse.
Lead is soft, cheap, and can be cut, squeezed and shaped.  If you aren't going to cut, shape, and finagle
straight tungsten in there, you may as well just use lead.