What sort of grease is one supposed to use on nylon gearing?
I have just replaced a nylon gear in my garage door opener and would like to put some suitable grease on it. I'm not complaining about the durability of the one I had to replace, it was probably getting on for
20 years old!I've squirted some silicone lubricant on the new nylon pinion but it feels as if something a bit 'stickier' would be a good idea.
Some say you don't have to lubricate nylon. Some say grease will attract dirt.
If you still want to lubricate your gears then silicone grease would be ok. There is a thought mineral based greases and oils attack plastics.
Nylon swells in contact with mineral oil.
Yes, I've seen that said too. However the maintenance kits for the door opener do include grease so, presumably, they think it's a good idea.
However I can't find any actual data showing what types of grease may affect nylon. The most specific I can find so far is:-
Nylon is generally found in pistons, tappet plates, nozzles, some contact housings, and lower end gear bushings. The plastic has good thermal and chemical resistance along with a low coefficient of friction. Fiber reinforcement can also be added to improve the strength of the plastic, but may make it unsuitable as a bearing material (BPF, 2019).
Generally, most all greases will work with Nylon parts in gearboxes. However, it has been reported that molybdenum disulfide, an extreme-pressure additive, can penetrate nylon plastic and weaken its structure (Gianattasio, 2000).
#are all the gears plastic? Often the small one on the motor is metal. One problem with plastic is the different way it behaves with temperature changes. If the gears are pretty enclosed then the sort of ordinary oil a bit like the 3 in 1 type seems pretty good. Make sure however that whatever the device is, ie garage door or whatever, does not have any tight spots that might put undue pressure on the plastic gears though, and that any sensors for start and end are aligned correctly too, you don't want the gears to strip due to a gummed up limit switch!
Brian
... and:-
Apart from the stripped nylon pinion (which had spread 'snow' all around the place!) it was all in pretty good condition. There are two pairs of nylon gears, no nylon/metal ones, and some standard metal bearings.
I've cleaned it all up, removed the snow and it's all back working now. I bought 4 of the nylon pinions for about £12 so it has been a cheap fix! :-) We have three garage door openers with the same mechanism so I thought 4 replacement gears would be a good idea.
dry PTFE, or graphite powder?
If it is cheap and easy to fix why lubricate them at all?
Why not? I?ve never dismantled a nylon gearbox that wasn?t packed with grease. I?m guessing manufacturers don?t do it for fun.
Tim
They have the expertise, time and effort to devote to it. For a non expert it may be easier to change the nylon parts more regularly.
Well I'd prefer not to have to take it apart and reassemble it too frequently! :-)
Car mirror adjusting motors use nylon gears, a worm gear on the motor shaft. They're slathered in silicone grease.
Yes, they always seem to have that 'vaseline like' but rather softer grease don't they.
Anyway, I've lubricated as follows:-
A drop of ordinary oil on the motor bearings and the other metal bearings.
A spray of silicone lubricant generally (should help keep corrision at bay anyway).
White grease (from an aerosol can) on the nylon gears.
Nylon is pretty compatible with mineral oils, I think it is not particularly critical. But, I'd agree with Clive and would probably go with silicone grease, if I had some to hand.
Most gearboxes tend to also have metal to metal bearing surfaces. The grease would be for this, and perhaps not the nylon content?
I saw they were the preferred lubricant, but I didn't see how they would "stick" to nylon gears without some carrier grease.
The only times I have seen PTFE and graphite mentioned is where the nylon gears come impregnated with these.
When I used to repair video recorders , tape decks and so on many years ago, we used white silicone grease either from a sq. Sort of looks like, and has the consistency of, toothpaste. But isn't!
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