What Bolster Pins Fit BLMA N Trucks?

[tehachapifan]

It appears that the BLMA trucks available in pairs do not come with bolster pins. Standard MT pins don't seem to fit (too tight). Aside from BLMA pins, which don't appear to be sold separately, what pins fit these trucks...preferably ones that don't have a ton of slop/play?

[nkalanaga]

I take a round file and (carefully) enlarge the hole until MT pins fit.

[jagged ben]

Most Atlas pins are smaller but maybe a bit too small.  I've also done what nkalanga has.  The truck holes only need a little bit of enlarging.

[tehachapifan]

Ok thanks, guys! Hoping I wouldn't have to do that, but it sounds like it isn't too bad.

[bbussey]

The MTL pins of that era.  That's what the BLMA trucks were designed for. When MTL retools certain common parts as the tooling wears out, they aren't necessarily to the exact specs of the previous version.  The bushing diameter of the standard MTL bolster pin has changed at least three times in the past 50 years.

The best option is to take a round-file and slightly enlarge the bolster hole on the BLMA truck, as stated.
 

[thomasjmdavis]

When MTL retools certain common parts as the tooling wears out, they aren't necessarily to the exact specs of the previous version.  The bushing diameter of the standard MTL bolster pin has changed at least three times in the past 50 years.

I learn new things everyday...but it does explain why some of the MTL pins in my 50 year collection of spare parts fit better than others. I hadn't put together that old pins and new cars (or vice versa) might be why.

[bbussey]

Same with the truck frames and the wheelsets.  I don't use their wheels because they are plastic, but features other than the flange shape and depth have changed over the decades as well.  The axle length has fluctuated around .540".  The distance between the points of the cone-shaped cavities in the trucks fluctuates.  For example, the original low-profile wheelsets do not spin freely in current trucks if I remember correctly.  I don't remember if the original ribbed-back wheels spin freely in the current trucks.  There have been other subtle differences as well.  The constant on the trucks is the external relief detail.

The couplers obviously have "evolved" as well, but those changes have been well-documented over the decades.

[eja]

If you have micrometer, drill press and a numbered drill bit set,  I would drill them out to size rather than file them.

[nkalanaga]

One batch of MT wheels, about the time Fox Valley first released their MILW horizontal-ribbed boxcars, and used on the FVM cars, wouldn't stay in the MT trucks they came with.  The axles were too short, so I replaced all of them with old Precision Master wheelsets.

They now have ESM metal wheels!