A week of wheels: FVM wheels in at Scaletrains

[peteski]

John,  I still prefer the conical hole rather than hemispherical one.  That design has been successful used for decades.

[JeffB]

John,  I still prefer the conical hole rather than hemispherical one.  That design has been successful used for decades.

Agreed...  Creating a spherical bearing for a coned axle sort of defeats the purpose/benefit of the coned axle.

Jeff

[mmagliaro]

I have used a little round burr for this, and yes, it works well.  Use the smallest one you have.  You are just trying to deepen the very pointy bottom of the cone, and it just has to let the point of the axle go in a hair more.  If you use too large a burr, the point of the axle can start gyrating around in the "bowl" you have created at the bottom of the cavity and the axle will wobble.
A jeweler's "bearing bur" "cone bur" or "Hart bur" works well too.  They are pointy and cone-shaped.  They make them in 45, 70, and 90 degree.  But that angle is not the angle at the point (where we want, I suppose, a 60 degree angle to be ideal).  It is the angle on the sides.  The 90 degree work best because the bur point can get all the way into the axle hole pocket and gently ream at the bottom of it.  Jeweler's supply places like Geisswein sell them.

[peteski]

Same...  I've found the pointed axle bearing cleanout tools (drills) lack the sharpness to bite into the Delrin/nylon that a lot of commercial trucks are made from.

Even before considering the quality of that reamer's cutting edges, to me just the length of the tool (0.593") is a no-go.  With many commercial wheelset's axle length being 0.540", and the widest 0.563, in order to insert the tool in the sideframes, they have to be spread out fairly drastically.




As shown here, this causes the reamer to not align with the center of the conical holem so if any reaming is don.e it will be off center when the sideframes relax back into their original position.

The tool should have been designed to be closer in length to the length of the wheelset's axles.  That way, during reaming the sideframe distortion would be minimal, and the modelers could squeeze the sideframes while reaming.

[Lemosteam]

John,  I still prefer the conical hole rather than hemispherical one.  That design has been successful used for decades.

@peteski , that's fine, but you must realize that the bottom of that cone has a spherical radius already (you cannot mold a sharp point in the bottom of a cone, its not manufacturable).  That's why it works- that sharp point on the axle rides on the sphere that's already there.

My method just moves that sphere a little deeper in the frame.

[peteski]

@peteski , that's fine, but you must realize that the bottom of that cone has a spherical radius already (you cannot mold a sharp point in the bottom of a cone, its not manufacturable).  That's why it works- that sharp point on the axle rides on the sphere that's already there.

My method just moves that sphere a little deeper in the frame.

My Point is that the axle endsdo not fit tightly in the axle cups.  There is a bit of play.  due to that design, the surface of the axle cone rides on the surface (not the end) of the cup. But I guess making the cone deeper by adding a small diameter hole (of any shape) to the bottom of the cup will likely work well enough. As long as the original 60 deg. conical shape is retained in the larger diameter of the cone which is in contact with the surface of the axle point.

[EdKap2]

Funny Ed3 mentioned this post to me. 
I just tried the reamer to “fix” an ancient car for the club’s “raffle layout.”  The reamer really spread the frames, which are softer plastic. I wondered if it was going to actually deepen/resurface the cup, but the wheelset did roll a bit better after a few turns.

BTW,  it is my experience that Intermountain wheelsets DO NOT roll well in Kadee or the later MicroTrains frames.  I’ve tried in both flavors of MicroTrains truck frames.  Eastern Seaboard Models do well in MicroTrains and most other brands.

[nkalanaga]

Intermountain wheelsets are too long to fit KD/MT frames.  IM uses 0.553 axles, and has for years.

[Mark5]

Intermountain wheelsets are too long to fit KD/MT frames.  IM uses 0.553 axles, and has for years.

Intermountain currently sells 0.554" and 0.537" wheelsets:

https://www.intermountain-railway.com/wheels.htm

Mark

[mu26aeh]

Intermountain currently sells 0.554" and 0.537" wheelsets:

https://www.intermountain-railway.com/wheels.htm

Mark

Latest IMRC wheelsets marked for MicroTrains cars are too long.  Myself and @DeltaBravo have bought packs that don't fit.  They measure out to .540 IIRC.  I've found some MT trucks that still work, but it's hit or miss

[nkalanaga]

Mark:  Thank you!  When I was trying to buy IM wheels all they had were the longer ones, and they were hard to find.