As well as 3D printing model trains and building model railroads, I do a lot of repairs to locomotives for fellow modelers. These range from simple wire repairs up to total motor and chassis rebuilds or replacements. One of the issues I come across is over lubricated locomotives, so in this post I will tell you a bit about why this is a problem, and how it should be done.
Some people have said that liberally lubricating moving parts will help preserve them if they are going to be stored for a long time and I can assure you this is not the case.
Over lubricating a locomotive can have the following progressively worsening effects:
It can cause the locomotive to lay a film of lubricant on the rails making the locomotive and others loose traction.
It can make it slippery to handle and possible damage the paint work.
It can make it easy for the mechanism to retain dirt and fluff, which will start to cause binding and over strain the motor.
Oil inside the motor, or on the commutator, can disrupted the flow of electricity to the motor making it run slow or roughly. (What is a commutator? see the image below).
Oil inside the motor on the armature can connect parts of the motor to the power or chassis causing arcing and bad running though intermittent shorting. (What is the armature? see the image below).
And the biggest problem, oil coating the commutator and brushes which will cause a dead short. This will in turn cause the motor to overheat and burn out; this is when the small gaps between the commutator plates blend into one, so the electricity just passes straight through.
I often get locomotives to repair where there has been smoke coming from the motor or a glow and buzz, rather than turning. This is normally a sign that the motor has become jammed or the commutator is shorting. The glow is lubricant and carbon, from the brushes, stuck between the commutator plates acting like a bar fire element. The smoke is usually the excess oil burning off from the heat being produced. If the commutator or brushes are heavily lubricated electricity simply doesn’t go where its supposed to. Sometimes if a motor gets to this stage it can get deformed from the heat and will never run as well as is should again.
One other issue I sometimes see is if the wrong type of lubricant has been used. Some are not plastic friendly and can cause gears and parts to break down.
So what should you do? The simple answer is ‘just a few drops will do, don’t over lube’ and this is the phrase on the package of the main lubricant I use from LaBelle.
Being an N Scaler I tend to use lubricants from LaBelle as they have a set designed specifically for N scale which are plastic friendly and very fine, but the principles are the same for all scales.
The three products in the kit are oil, gear lubricant and grease.
LaBelle 108 is a very fine oil with a high viscosity. It is used, sparingly, for moving metal components like valve gear and side rods on steam engines. It can also be very sparingly used on motor bearings and brush slides etc. but try not to get any on the actual brushes or commutator. (LaBelle 107 is designed more of larger scales such as HO and O).
LaBelle 102 is heavier than the oil but not as thick as grease and is designed for exposed gear boxes. It contains PTFE (Polytetrafluoroethylene) which has been called “the slickest substance known to man” and is the parent chemical of “Teflon” which is a registered trademark of Dupont Chemicals. It’s great for metal gears and axles.
LaBelle 106 is a grease, which also contains PTFE. Their slogan is ‘just a dab’, and they are right. It’s designed for plastic gear boxes and worm gears. A dab on one of the gears will work its way through the box and onto any worm gear. Again, a dab is all you need, over lubricating with grease could start to bind the gear box.
There are lots of companies making similar products, and any good model shop should be able to guide you to the right one for your model.
But which ever you decide to use, remember just a drop is enough.