Old AHM/Rivarossi 4-4-0 upgrading

[Schraddel]

Fortunately i am the lucky owner of lathe:


A little too big in size, but it was an one time non recurring opportunity and i decided to buy this used lathe. It was used, but not worn and came with some attachments. So i bought it for the equivalent of three H0 steamers and relinquished to buy these locos.





For turning down deep flanges i made pick up devices which keep hold of the wheel directly. I turned this pick up devices out of aluminium round stock. The bore inside is turned too and must be individual made for each wheel diameter. The trick here is to use the 3° slope of the wheels tread surface. The wheel wedges into the bore, as the diameter of the bore is app. the diameter of the wheel tread halfway between the diameter on the outer edge and the diameter on the inner edge were it descend to the flange.
Slightly set, not ramming, the whole pair of driver ( with a single wheel it will work too) into the bore. It is centered in means of diameter, but it still wobbles because it is not centered in the means of lateral out of true.
To center it let the late turn in the lowest rpms as possible. Here my lathe is equipped with a electronic controller and like an decoder it has a kind of BEMF.
Then push the turning steel carefully and slowly against the wheel flange. In this stage it should not cut, but only slightly pressing against the flange. The effect is the wheel will be centered lateral too. When it is centered and rotating round, then apply the tailstock gently with light pressure only.
Before, you have taken measurements how much material of the flanges have to be turned down. Arrange the turning steel and reduce the flange by cutting from the side. Keep the rpms low and feed only slowly for not overheating. It will take a longer time, but it avoids the melting of plastic wheel centers. The turning steel have to be kept as sharp as an razor blade to enable proper turning at low rpms.
Then shift the set of wheels and turn down the other wheel.
Meanwhile the wheel not fitted into the pick up device is turning and free acessible. Take a sharp file and break the sharp edges at the flange top. Then round and smoothen them out. Especially the transition from the outer flange side to the top of the flange is crucial for a smooth running of the wheels lateron.
Shift again and smoothen out the other wheel.
Control with the NMRA gage or a caliper.

N.B. If traction tires are involved take special care. Sometimes the traction tires may staying mounted, but sometimes they have to be removed before turning. And be aware there is only the thin rim between the outer face of the wheel and the groove for the traction tire. Be very gentle and careful to this kind of wheels.

With this technique the surface areas of the wheel which are running onto the rail will be untouched. Surface finishes also will be kept untouched.





Turned down flanges of a Rivarossi wheel with plastic center. Here it was the goal to make one running loco out of the remains of two locos and get rid of the traction tires. Therefor singular wheels are to be seen.





The result. This 4-8-4 has have had before deeep flanges Märklin Hi Rail style.


Cheers Lutz

Edit: Grammatics