Did MT Axle Lengths Change at Some Point?

[tehachapifan]

This one's got me scratching my head a bit. Was changing out some MT wheelsets with some FVM wheelsets and did a few cars that rolled very freely, as they typically do. Then, I did another car with MT trucks and the wheels were quite tight and all 4 did not roll freely at all. These are definitely MT trucks and I'm definitely using FVM wheels intended for MT trucks (same bag of wheels I just used on the other cars). This has me wondering if MT truck axle lengths might've changed at some point?

[Chris333]

I got a bag off .553" axles and all but 19 were .540".

[tehachapifan]

I got a bag off .553" axles and all but 19 were .540".

Ugh! That's not good news!

[Chris333]

For me it was because I was looking for .540 and couldn't find them. I was using 3D trucks so I just widened them to .553. Then ordered .553 wheels.

[tehachapifan]

So, I busted-out the digital calipers and the wheels in question measured out to .540. Looking at a separate set of MT trucks with these same wheels, the axles have a little side-to-side play. On the trucks where they don't spin as freely, there is no side-to-side play at all. Strange!

[peteski]

So, I busted-out the digital calipers and the wheels in question measured out to .540. Looking at a separate set of MT trucks with these same wheels, the axles have a little side-to-side play. On the trucks where they don't spin as freely, there is no side-to-side play at all. Strange!

As you noted, little side to side play is desired.  The pointy axle ends are not supposed to be touching the center point of the inside of the truck cones.

Since you do have digital calipers, have you measured the original MTL wheels which came out from both trucks.  Are they all 0.540"?

[Chris333]

Here is my post:
https://www.therailwire.net/forum/index.php?topic=47536.15

[tehachapifan]

As you noted, little side to side play is desired.  The pointy axle ends are not supposed to be touching the center point of the inside of the truck cones.

Since you do have digital calipers, have you measured the original MTL wheels which came out from both trucks.  Are they all 0.540"?

Unfortunately, the battery in my hardly-ever-used digital calipers is going dead and I was lucky to get it to read the metal wheels. Of course it's a button battery that I'll need to order. I'll see if I can sweet talk it into another reading later today.

[davefoxx]

Unless you've got painted freight car trucks and you're worried about the paint flaking off, bend the sideframes out and that may give you enough play to make the trucks free-rolling.  I've done that trick more than once when I was in N scale.

DFF

[Englewood]

Did you buy the offending car new? Maybe a previous owner changed the trucks out. Is it a newer release? It's been a while since I changed wheels out, but I'm curious to know.

[peteski]

Unfortunately, the battery in my hardly-ever-used digital calipers is going dead and I was lucky to get it to read the metal wheels. Of course it's a button battery that I'll need to order. I'll see if I can sweet talk it into another reading later today.

LOL!  My digital caliper gets used a lot (and not just for measuring things). It is always on my workbench.  If you don't use it often, take the battery out.  The on/off switch does not shut it off - it just turns the display off, but the power is still drained from the battery by the rest of the circuit.  That way the battery will last longer.  Mine lasts about 1 year (when not removed from the caliper, since I use it all the time).

Most calipers use LR44 button battery - it is probably the most popular button battery, because many cheap Chinese gadgets and toys use those batteries.  You can easily pick one up at any supermarket, pharmacy or a dollar store.  Just pick up couple of them next time you visit any of those stores.

I buy mine from Digikey (10 at a time) because they are inexpensive, and good quality, and I store them in my fridge (they take up very little room). And yes, I have other gadgets that use those batteries. For example a kitchen timer is one such gadget.

[tehachapifan]

Unless you've got painted freight car trucks and you're worried about the paint flaking off, bend the sideframes out and that may give you enough play to make the trucks free-rolling.  I've done that trick more than once when I was in N scale.

DFF

Thought about that but I'm still curious as to what's going on. They're not bent inward at all.

Did you buy the offending car new? Maybe a previous owner changed the trucks out. Is it a newer release? It's been a while since I changed wheels out, but I'm curious to know.

It is a car that I added MT trucks to many moons ago. Definitely MT trucks.

LOL!  My digital caliper gets used a lot (and not just for measuring things). It is always on my workbench.  If you don't use it often, take the battery out.  The on/off switch does not shut it off - it just turns the display off, but the power is still drained from the battery by the rest of the circuit.  That way the battery will last longer.  Mine lasts about 1 year (when not removed from the caliper, since I use it all the time).

Most calipers use LR44 button battery - it is probably the most popular battery, because many cheap Chinese gadgets and toys use those batteries.  You can easily pick one up at any supermarket, pharmacy or dollar store.  Just pick up couple of them next time you visit any of those stores.

I buy mine from Digikey (10 and a time) because they are cheap and good quality, and I store them in my fridge (they take up very little room). And yes, I have other gadgets that use those batteries. For example a kitchen timer is one such gadget.

Thanks for the info! Yeah, it never dawned on me to take the battery out.

[thomasjmdavis]

An LR44 and a 357 are the same size and specs(at least, according to the chart I just found on the always reliable internet), but is one superior to the other, or is it just a matter of 2 different codes for the same thing?

[peteski]

An LR44 and a 357 are the same size and specs(at least, according to the chart I just found on the always reliable internet), but is one superior to the other, or is it just a matter of 2 different codes for the same thing?

Yes 357/303 button battery is the same size, but it uses Silver Oxide chemistry.  LR44 uses alkaline chemistry.  Solver Oxide battery has slightly larger capacity, and a flatter discharge curve (so it remains at is full usable voltage until most the very end, when the alkaline battery's voltage starts dropping off earlier.  The end result is that Silver Oxide batteries last longer than alkaline (but they cost more).

I usually look up button cell battery info on https://en.wikipedia.org/wiki/Button_cell

[pedro]

LOL!  My digital caliper gets used a lot (and not just for measuring things).

The mind reels trying to think of possible non-measuring activities that could be done with digital calipers...