peter_shaw wrote on 2023-09-25, 11:36:

Hi, i just dissasembled an old floppy disk drive. It was owned by a heavy smoker. The worm screw was covered with black crusty g […]
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Hi, i just dissasembled an old floppy disk drive. It was owned by a heavy smoker. The worm screw was covered with black crusty goo, which I removed with Isopropanol. I guess i have to re-lubricate it now. What's best for that purpose?
I have:
- bicycle chain oil
- WD 40
- Silicone based spray / oil

or is that all not good?

AFAICR, the original WD40 is meant to help unseize stuff, but is not recommended as a long tern lubricant (there may be actual WD40 branded lubticants too). Best practice is probably to clean out originally lubricant and use a fresh one meant for this kind of application. Mixing old and new lubricant types can be an issue, AFAIK.

I am short on time to check that if all the above is accurate right now, but someone here who actually knows about this stuff way better than I do will probably chime in. Otherwise, please take my above assertions as a starting points for further research, not as actual recommendations.

Bike chain oil is a pretty broad term... in any case, it's meant for metal-on-metal applications, if in the drive it would come into contact with plastic parts it may or may not react with that. WD-40, just no. Use only for un-sticking stuff and/or displacing moisture, then clean it right off afterwards. Silicone based should be fine I think?

peter_shaw wrote on 2023-09-25, 11:36:

Hi, i just dissasembled an old floppy disk drive. It was owned by a heavy smoker. The worm screw was covered with black crusty g […]
Show full quote

Hi, i just dissasembled an old floppy disk drive. It was owned by a heavy smoker. The worm screw was covered with black crusty goo, which I removed with Isopropanol. I guess i have to re-lubricate it now. What's best for that purpose?
I have:
- bicycle chain oil
- WD 40
- Silicone based spray / oil

or is that all not good?

No oils (esp. mineral based), it'll only get sticky and attract more dirt soon enough. It's usually a plastic notch on metal screw so it will work dry, so if you need to use now it and it's already cleaned it is better to leave it as-is. Some 5.25" drives might use a worm screw but metal on metal so that does need lubrication, and mineral based grease is OK in that case.

WD40 and any thin oils are good for a quick "fix" in a pinch but not for proper lubrication. You use those, only if necessary, before the proper cleaning just to get the drive working once. Preferably though any drive so dirty that it doesn't work or is just too cacked with smoke residue (I don't deal well with that so I always clean and wash anything used by smokers) should be disassembled and cleaned.

Preferably use something dry, like PTFE grease. Silicon grease (used in car brake systems) is also good, and plastic friendly, but it's not as dry as PTFE. By the way, clean the polished rods the sled (with heads) moves on, those you really don't want to lubricate at all, even with PTFE. The bushings in the sled are plastic or brass, they will never seize as long as there isn't a layer of dirt - but often there is, and this is a perfect example of both cigarette tar / tobacco residue and poor lubrication points doing harm. To clean the rods and bushings you might need to unsrew the rod holders, just take care not to move the stepper motor and the track 0 sensor, or you'll need to recalibrate the drive after reassembly.

Do not put WD40 in there. First, it is not really a lubricant and isn’t meant for such applications. It’s main job is to clean and anti-seize and you should always add a proper lubricant. It also dries quite fast and lubricating effect it has, doesn’t last very long. Second, it attracts and removes dirt and because it has very low viscosity, rotating components spray the goo all over the place.

I personally use silicone grease, because it doesn’t react with different materials and is very good lubricant. Something very similar was applied from the factory.

Ok thanks for the pointers. It seems to be metal on metal by the way.
Still some more cleaning to do...

peter_shaw wrote on 2023-09-25, 15:46:

Ok thanks for the pointers. It seems to be metal on metal by the way.

Yes, but that's the spring on the top, bottom part is plastic. You need to be sure any grease (this is too exposed for oils) used here will not affect the plastic parts. Silicon grease is safe, PTFE is too but the additives (that help with application) are the tricky part. On this 3.5" drives you do not want to touch the 2 screws that hold the stepper motor, and anything that ties the track zero sensor to the case. Everything else can be taken out and cleaned if need be - there are some places that use grease and are metal only but there isn't much friction so feel free to just use one kind of grease (PTFE or silicon) on everything to make it more simple. Frankly it would work dry as well and if the floppy drive is not going to be used much it might even stay dry, the worm screw is really the only place where it is somewhat important to apply some lubrication.

I prefer white lithium grease for drive assemblies. A little amount goes a long way.

I agree with wbahnassi, I use lithium grease for all my floppy drives and it never failed.

I used the silcon grease spray, it looks ok I guess:

https://vimeo.com/868069723#

Thanks for the help!

I use the white grease too and use a tooth pick to apply small dabs where needed.....

Lithium grease is mineral (petroleum) based, and not suitable for rubber and some plastic parts. But it works very well in metal on metal friction points. Silicone grease is safe for platic and rubber and all kinds I've seen are also non-toxic (even ingested) although I'm not saying there are no exceptions, always best to read the instructions on the box.
Both are not dry as PTFE is but are cheaper and find more general uses around the house (and car) so people will often already have it. Obviously it's always better to pick the optimal one depending on what's needed - PTFE if dry, silicone for rubber/plastic, petroleum based for metal. Especially iron/steel parts that tend to rust will benefit from mineral grease as those tend to close the pores of the metal and prevent water/oxygen exposure.

For floppy drive it's really not very critical what is used, so long it's not too much, or too thin (evaporates or runs off) and applied only where needed.