This Old Locomotive...


Ken Clark
 

In a message dated 2/11/00, 8:47:39 AM, HOsteam@onelist.com writes:
<<Well, I measured the drivers, and they measure about 0.71 - 0.72 inches in
diameter, depending on where on the taper I measure (the RP-25 profile has a
taper to provide a "dihedral" to improve tracking). That scales out to about
a 62" driver.>>


Without having my PFM Calipers and KTM models at work, I suspect you have the
standard KTM "nominal" 63" drivers, slightly undersized due to oversize
flanges, but not as bad as the Akane 63" drivers on their cab-forwards. I
have swapped KTM spoked drivers between Mikados, 2-10-2s, AC's, 4-6-0s, with
no hint of mechanical problems. When I put a "matched set" of Korean 57"
drivers in a WSM SP T-31 frame as part of Kit Bashing a NWP #182 those
drivers took a lot of TLC to run smoothly in the Japanese frame. I believe
Kemtron, therefore PSC, had cast driver centers for the 73" and 63" drivers.
One potential problem with mixing in Bowser drivers, the japanese models use
metric sizes, 3mm axles etc... if you are comfortable replacing/rebuilding
the loco frame then turning/truing a cast driver center should be a piece of
cake.

With the new more efficient motors, the eletrical conductivity of the wheels
is less important than before. I think there would be a market for mild
steel replacement tires for drivers in the common sizes (for SP at least) of
57", 63", 73", 80". Traction would be improved, wear reduced, and there
would be no plating to wear off. You ever hear diesel fans complain after
switching from Athearn iron wheels to NWSL plated wheelsets about losing a
lot of pulling power?

ken


Arved@...
 

Well, I measured the drivers, and they measure about 0.71 - 0.72 inches in diameter, depending on where on the taper I measure (the RP-25 profile has a taper to provide a "dihedral" to improve tracking). That scales out to about a 62" driver.

The good news is that Bowser/Precision Scale has drivers in this size. The bad news is they are all spoked. Not a universal disk, boxpoke, or scullin in the whole lot :-(.

What I need, ideally, is 4 spoked drivers and 1 universal disk driver with matching crank throws, as close to 62" as possible. I figure I can work out axle diameters, gear/gearbox mounting and such myself, but scratch-building a driver center is a tad beyond my skill level.

I'd just like to resurrect this ol' girl. In the worst case, I do all this work, and end up with a spoked main driver.

Have a great weekend,

- Arved

P.S. And yes, BudFrogs is a real virus, but not a computer virus. It's a social virus dependent on the gullibility of those it infects.


Ken Clark
 

Steel will rust ...

Actually, I think there is too much oil on our models mechanisms for this to be a big problem. Considering the axles are steel, and most drive shafts as well. I've only encountered a couple of rusty steel shafts in working on several hundred models, and those models looked like they swam across the Pacific, the brass was in even worse shape. I agree on "stainless" Key tried and produced some engines with SS tires, and they were very slippery. And many, if not most O scale models have steel tires, and they don't get as much mileage as their little HO cousins.

ken


Jon Miller <atsf@...>
 

I agree that it's time for better tires on steam engines. Solid Nickel
Silver would probably be the easier to do as NWSL seems to have no problem
doing solid NS wheels. Steel will rust and SS steel, I think, is slippery.
But any kind of steel would be hard to do on the screw machines which I
think is what is used to make tires and wheels. I don't know that much
about metals but I think plating is an old design and should be changed. I
think some of the new brass models use NS but the prices!
Some of the new plastic steam coming out might well think about changing
tire material.

Jon Miller
AT&SF
For me time has stopped in 1941
Digitrax DCC owner, Chief system
NMRA Life member #2623
Member SFRH&MS