Kato Mikado driver diameters and cutting TT grooves

[mmagliaro]

When I noticed that a Kato driver hole exactly fits snugly over a 00-90 screw, I thought I would try
putting a 00-90 through one with washers and nuts on it, so it could be chucked in a drill (or mill)
and spun accurately to cut a traction tire groove in it.

On a Kato TT driver, the diameter of the tread where the tire doesn't go is 0.369  (EDIT: error was 0.469".)
The diameter in the groove is 0.355 (EDIT: error, was 0.455), so the groove depth is .014/2 = .007

Armed with that info, I chucked up a plain #4 driver (the type with no crankhole and a gear on the axle).
As I cut, I had just begun to make some depth when I cut the metal tire band clean off.  Whoops.

I then noticed that the metal tire band on a "real" TT driver is a good bit thicker than
the bands on the normal drivers.  In other words, they are not the same, so cutting a groove
in a plain driver is probably not possible.  It sure wouldn't be easy, at any rate.  It would be tricky
to get enough depth without making the metal band so thin it would fall apart.

I also discovered that the diameter of the Kato drivers varies quite a bit... the TT was
.369,
Others are .381, .374 

(EDIT: Error was .469. Others are .481, .474.)

That seems like a lot of variation for a factory driver.   
And these are ALL the drivers with no crankholes and with gears on them, so they are all #4 drivers.

Perhaps other people have noticed this.  Is there a reason for this variation?

[Big4Man]

Huh? This just begs the question.....Why?

Are you wanting to modify these traction tires at all? Kato sells a traction tire replacement driver set for this lokie that may be available if you look around.

Are you trying to pull a toaster over a waffle iron with it? 

Just sayin'

Dan

[SkipGear]

Huh? This just begs the question.....Why?

Are you wanting to modify these traction tires at all? Kato sells a traction tire replacement driver set for this lokie that may be available if you look around.

Are you trying to pull a toaster over a waffle iron with it? 

Just sayin'

Dan

Because a Kato Mikado without traction tires is pretty much a useless loco. It won't pull more than about 15 cars on level and grades are out of the question. Adding the traction tire to them brings them into the realm of respectability, around 40 cars or more on level.

There are many of us that would like to at least come within half of what the real loco could do. I know Max has a GHQ bodied remotored Mikado based project that has pulled close to 100 cars. I have a Mikado based loco that will pull 80 maxed out and 70 all day without a sweat. The loco has possibilities, but without traction tires my Bachmann 0-6-0 will out pull it.

PS. Kato Traction Tire drivers have been sold out for years. There was a replacement batch that hit a few months back and they lasted less than a week at Kato. Kato is not sure they will run them again. There are still a lot of anemic Mikado's out there that could use some help.

[hpwrick]

Magliaro, Tony and of course everyone tuned in here,

This may seem redundant as we have both discussed this before and yes we even hammered on it over on the A Board and TB.

Has any consideration been given to cutting a groove,  and then filling it with Bull Frog Snot?    The stuff works for me and I highly recommend it.   Suggesting,  it may be the last time you have to use it and/or worry about TT's ever again.

I can't believe what it has done for a friend's HO locomotives and my N scale stoves.   Amazing stuff. 

Just sayin!   A lousy expression that is otherwise meaningless but works here.

[SkipGear]

Magliaro, Tony and of course everyone tuned in here,

This may seem redundant as we have both discussed this before and yes we even hammered on it over on the A Board and TB.

Has any consideration been given to cutting a groove,  and then filling it with Bull Frog Snot?    The stuff works for me and I highly recommend it.   Suggesting,  it may be the last time you have to use it and/or worry about TT's ever again.

I can't believe what it has done for a friend's HO locomotives and my N scale stoves.   Amazing stuff. 

Just sayin!   A lousy expression that is otherwise meaningless but works here.

BFS works, but not nearly as good as a proper traction tire. I think the point of Max's post is that he found out is that you can't cut a groove in the existing rims, they are just not thick enough. So we really don't have the option of either rubber or BFS without more drivers.

[Chris333]

A fellow from the Atlas forum cut a LL 2-8-4 tire for me, I wonder if there is more meat on those bones?

Wondering what rpm you use when turning drivers?  Do you use a special cut tool?  I have nothing but trouble every time I try. It is very hard to get the driver clamped tight enough. 

I have not tried to cut a Kato mike driver yet...

[Big4Man]

FYI...

http://www.ebay.com/itm/KATO-11-604-Pair-of-N-scale-Mikado-4-driver-with-traction-tire-NEW-/350569793821?pt=Model_RR_Trains&hash=item519f96891d

They are out there on a regular basis...

I was just wondering what was "driving"  mmagliaro to go to these great lengths on his Kato Mikado?

I have a couple of the above drivers stashed away that I could part with if needed.

Dan

[Chris333]

Well if you replace a few with the TT driver your left with spares so why not try.

[SkipGear]

FYI...

http://www.ebay.com/itm/KATO-11-604-Pair-of-N-scale-Mikado-4-driver-with-traction-tire-NEW-/350569793821?pt=Model_RR_Trains&hash=item519f96891d

They are out there on a regular basis...

I was just wondering what was "driving"  mmagliaro to go to these great lengths on his Kato Mikado?

I have a couple of the above drivers stashed away that I could part with if needed.

Dan

$30 for a pair when you include shipping? That is not horrible considering they originally sold for $7 per axle and were available at your LHS. The problem is, that supply won't last forever. There are a finite number of them available.

I have 8 Mikado's/Chassis setting waiting for projects and not enough tires for them. I may never get to all of them but if I do, it would be nice to have an option.

[Lemosteam]

Max, that's quite interesting.  This means that kato not only tooled up unique machining for the driver wheel but also a unique casting for the spoke insert.  If I might ask, could you measure the OD of the spoke inserts?    Surprising also that a groove depth of a mere .007 in. cuts thru the original wheel's ID.  Was the bottom of your groove flat?  Curious what tool you used? 

I also looked up the LL Berk thread and saw that the gent was using a cutoff tool and chucking the bearing pilot into the machine wiith the back of the whell tight to the chuck teeth.

Crap that closes off some of my options too...

[mmagliaro]

I assumed that the reason I was trying this was obvious, but  the questions make it clear to me that it was not.

Tony and others have hit some of the points, but I'll explain.

1. Those traction tire drivers from Kato periodically dry up, and in dry spells, they have sold for $40 or more on eBay, if you can get
one at all.
The current supply of them is likely to be the last one there is.

That eBay listing hasn't completed yet.  Searching the "completed listings", I find that typically, those drivers go for about $20 a piece.
There were a few bargains, like one sale that went around $20 for a pair.  But most go for more.   I suppose a $20 bill isn't bad
considering how much of an improvement it makes.  But they will get a lot more expensive when they dry up, which won't be long now.

2. Cutting a groove to fill with Bullfrog Snot would probably not make sense.  If I were going to use BFS, why cut a groove at all?
I would just apply it to the driver.
As Tony already mentioned, it doesn't work as well as the real traction tire.  We've both tested BFS against the real traction tire and it did not work as well in either of our tests.

3. I did successfully cut a groove in the 2-8-4 LL Berk, and I did it an insane way - running a Dremel cutoff disk right into the turning
driver while the engine ran on its back.  I do not recommend this.  I never thought it would do anything except hack up the wheel,
or at the very best, make for an awful, non-uniform groove that would wobble all over.  But no.  It worked great.   I think that
the spinning Dremel disk had a tendency to keep the driver centered and level as it cut.     I had a post
on this on the Atlas forum a few years ago.  So yes, the Berk rims must be thicker.

=================================
So, the "short answer" is that I was simply trying to see if a TT driver could be made out of a regular driver reasonably easily,
so that when all the real TT drivers are gone, there is an alternative.

I'm wondering about the rim on Spectrum 2-8-0 traction driver.  I wonder if it's the same size, or close enough, that it
could be pressed off the Bachmann wheel center and popped onto the Kato, or if the whole driver could be used outright.
I've got some around here.   Time for an experiment....

[peteski]

As others have mentioned, Kato Mikado without a traction tire driver is pretty much useless (which is too bad for such a smooth running and well designed loco).  For few years traction tire drivers from the last run were worth their price in gold! After years of modelers pleading with Kato USA (and after years of Kato USA pleading with Kato Japan), around last December another batch of those drivers was produced. But they are all gone again so either Kato again misjudged the demand or speculators bought them all out.    That is really too bad. There was a mention of Kato producing yet another batch but I'm not so sure about that.  Funny thing is that another small batch of (never to be seen) Mikados (Kobo version) showed up again at MBK.  But going back to traction tire drivers, I was lucky enough to buy 8 of them from the latest run at a discount from MBK.

As far as the drivers go, I measured (using digital caliper) couple of my Mikados and my results were quite different from Max's. All the drivers have consistent diameter.  Here are the measurements:
                                          Driver          1               2               3                4 no tire        4 w/tire
Dia. of the driver's metal tire   ------- 0.372"     0.373"      0.372"      0.372"            0.374" with tire, 0.363" metal rim, 0.352" groove
Dia. of the drivers flange  ------------  0.424"     0.424"      0.424"      0.424"            0.424"
Dia. of the drivers insert opening  -- 0.340"     0.340"      0.340"      0.340"            0.323"
Dia. of the insert.    -------------------- 0.335"     0.335"      0.335"      0.335"            0.320"

I was also very surprised that Kato produced a whole new metal wheel and spoke insert just for the TT driver. But then again, Kato likes to over engineer things (no that there is anything wrong with that).  I'm pretty sure that they did that because otherwise the thickness of the wheel at the groove area would have been very thin.  The groove is 0.0055" deep. that makes the metal in the groove area 0.0145" thick.

If they made the TT driver using the standard driver then the thickness of the metal in the groove area 0.006"  That would be pretty darn thin! Too thin. I expect that the would have problems reliably turning their wheels without the outside of the metal tire tire breaking off.

Lemosteam:   I would look at this from a different perspective. I suspect that if the traction tire driver wasn't an afterthought, Kato would have made all the drivers with the same dimensions as the TT driver (to simplify production). But of course only the TT driver would have a groove in it.

Here are some photos of the difference between standard and traction tire driver. The difference is quite obvious.  In case it isn't, the TT driver is on the left.



In this photo I splices quarter of the standard driver on top of the TT driver. I aligned it by the edge of the metal tire (the difference of the flange depth on the right side is caused parallax error of the camera (it wasn't perfectly centered and perpendicular over the driver).

[Lemosteam]

peteski- great photos and superimposing- thank you for the measurements as well. 

Max, if the Bachmann bearings fit into the kato frame (3mm I think) then you may only need to swap the gears (unless the teeth are the same).  Getting the gear tooth alignment to the quartering (for looks only, I realize the soderod does not attache) might be difficult but you run the same risk if you push the Bachmann drivers onto the Kato shaft, not to mention the kato shaft is octagonal, not sure about the Bachmann shaft.

For additional evidence of the Kato Traction Tire improvement and the reason so many gobbled these up:

 

[rogergperkins]

I am more optimistic about the traction tire supply; I noticed an announcement of a new release of the 2-8-2 with DCC installed.  Good to have a "just in case" fall back position, if my optimism is misplaced.

[mike_lawyer]

I was lucky enough to purchase two of the traction tire drivers for my Mikados when the last run came out.  As others have said, without the traction tire, the Mikado is a poor puller.  With one, and some weight on the loco, you can pull almost 100 cars with a good motor.  Max has accomplished that with his I1 conversion, and I have had the same experience with my PRR I1 conversion.  In fact, I was pulling about 50 cars around my layout last night (which is the max for my layout size).

I recall a thread on the old Atlas board some years ago about trying to use the Bachmann 2-8-0 traction tire driver for the Mikado.  If I recall correctly, the Bachmann driver is smaller than the Mikado driver, but I could be wrong.  I am operating off memory.  If it is the same size, you could pop off the Bachmann drivers and install them on the Mikado wheel shaft.