Worn Gears - what am I looking for?

[curtis]

I'm currently in the process of digitising one of my LGB 2070s (U-Class). Given it's age, I've had to strip it right down to the block which is probably a good thing because there is a bunch of dried up grease that I needed to clean up.

One thing came to my mind while looking around was the gear. Given the age, I thought I'd check to see if the gears were worn and then quickly realised I wasn't actually sure what I was looking for. Any tips / advice / pictures in your libraries of what I should be looking for to assess the health?

Curtis

 

[dunnyrail]

oh is this a 3 pin chassis?

 

[PhilP]

Basically, if the teeth of the worm-wheel (the gear driven by the worm) have been worn concave (dished).

PhilP

 

[phils2um]

If it's an old clam-shell, 4 digit model number loco don't lose those little ball thrust bearings on both ends of the motor shaft! The old motors didn't have built-in thrust washers/bearings like the newer ones have. I use a dab of grease to keep them in position in the motor shell when I put things back together.

 

[Paul M]

and then quickly realised I wasn't actually sure what I was looking for.

I wouldn't worry Curtis, that's a common problem when your age increases

 

[Paradise]

Also. Only use plastic compatible grease.
Labelle #106 grease with PTFE** – Labelle-Lubricants

 

[curtis]

oh is this a 3 pin chassis?

It's one of the old ones - before they had skates. There were no-pins (I converted a later Spreewald that had pins) but the motor block connected directly to the brass strips from the wheel pickups. It wasn't -too- much trouble.

Basically, if the teeth of the worm-wheel (the gear driven by the worm) have been worn concave (dished).

PhilP

Thanks! I figured it would be visible but I couldn't see anything so wanted to check instead of making assumptions.

If it's an old clam-shell, 4 digit model number loco don't lose those little ball thrust bearings on both ends of the motor shaft! The old motors didn't have built-in thrust washers/bearings like the newer ones have. I use a dab of grease to keep them in position in the motor shell when I put things back together.

I take those out as soon as I can and keep them in a tray. Not something I'd like to try and replace!

Also. Only use plastic compatible grease.
Labelle #106 grease with PTFE** – Labelle-Lubricants

I have the Massoth lubrication - but I've noted this for the future, thanks!

 

[Rhinochugger]

I thought I'd check to see if the gears were worn and then quickly realised I wasn't actually sure what I was looking for.

Curtis

Teeth?

 

[curtis]

Indeed, but having no reference point what what worn looked like, I didn't know if it was one of those things which was obvious upon seeing it or more more subtle. My sense from this thread is it is more obvious. The loco is running fine after reassembly at least!

 

[Greg Elmassian]

if you look at the teeth (after the gear is cleaned) uneven wear patterns will be noticable, but what Philp said,

the gear that engages the worm (the long skinny is the "worm", the gear that engages is the "worm gear".

Normally the worm is made of metal because it is smaller, less surface area, thus would wear faster. so the "worm gear" will wear. If the gears are not meshed fully, the worm will touch the worm gear just at the tips of the gear teeth, and the excessive force over a smaller area allow the worm to wear a concave surface in the worm gear.

good worm gear

worn gear:

 

[curtis]

This is really helpful! Thanks, Greg. I've got a frame of reference now

 

[Greg Elmassian]

note that in adition to being worn, the alignment side to side is a bit off, thus the concave part is not centered.

Typical situation, and you see the 2 small screws that hold the motor to the "frame", they often come loose, and you have to basically pull the loco apart to get to them to tighten them, so a common occurrence, you test by wiggling the motor, and if there is ANY motion in relation to the metal frame, the gear's days are numbered.

Greg

 

[LGB333]

Also. Only use plastic compatible grease.
Labelle #106 grease with PTFE** – Labelle-Lubricants

Massoth Gear Grease is also excellent..........I only use it on my LGB locomotive repair and restoration work.

 

[Greg Elmassian]

I used massoth gear grease on my hair too! made it stop squeeking...

Seriously, every post seems to be selling something.