3D Printed Gears for 800K Floppy Drives like MP-F51W-03

[JDW]

As many of you know, there is a small eject gear in 800k floppy drives which often breaks, and I've seen some replacements sold on EBAY.  The only auction I could find with a reasonable price for the gear and reasonable international shipping (to Japan, in my case) is this:

PMMA plastic in mold:

https://www.ebay.com/itm/Apple-Macintosh-1x-GEAR-for-800K-or-2M-SONY-FLOPPY-DRIVE-MP-F51W-MP-F75W/333463751453?hash=item4da3fd0b1d:g:1ucAAOSwhQhY0iTg

Here is an auction with a reasonable product price but which sadly doesn't ship outside Australia, and no plastic material is mentioned:

https://www.ebay.com/itm/2-x-Macintosh-Eject-Gear-for-800k-1-44MB-MP-F51W-and-MP-F75W-Sony-Drives/293587299042?hash=item445b2aaae2:g:E0QAAOSwggJexjMh

I am starting this thread to gather your experiences.  

From what I understand PMMA is rather compared to ABS or PC.  So it would seem that buying that is basically buying the same kind of gear we have now, which probably will break at some point in the future.  Metal would be idea here, but nobody makes one of those.  I would think PC would be a good #2 choice, but I cannot find any of those.  No ABS either.

I would appreciate hearing your thoughts.

Thanks.

 

[Franklinstein]

Somebody on Yahoo! Auctions was selling gears for about 2000 Yen each. Kind of expensive, and they don't seem to be available right now. I bought a bunch of these a year or so ago and they've been great so far, and it says they ship worldwide. The set of 4 gears averages about $6/ea, though of course shipping will increase that a bit. 

Anyway I don't know what the orange gear was made from, but it was likely deliberately made from a soft material to reduce noise. Using a replacement gear of any material will likely get you something stronger than stock, which in most cases lasted over 20 years anyway, but it will be a little noisier with a harder material. If you use them regularly your new gears will last as long if not longer than the originals: most failures of the original gear seem to be because the grease has hardened in place and/or the orange gears have undergone a chemical reaction, weakening and turning green where the plastic has been interacting with the grease and brass gear of the motor for the past decade or so

 

[jjclay]

Hi JDW

I ordered a couple of gears off the Italian guy in your first link, and when they arrived last year I was pleasantly surprised with them.

Having finally got around to my Mac Plus repairathon a week ago (some of which I filmed and inspired by you might put a video or two together), I got around to using one of the two replacement gears on an 800k Sony floppy drive whose gears had shredded in the typical way. My observations are:

- the gears look high quality - being moulded there are no 3d printed lines etc.

- don't know how the mound was obtained, but the gears they produce are a perfect fit

- really easy to replace the old 'orange' gear

- on first eject attempt, despite a full clean and sufficient lithium grease it seemed to eject a little 'strained' / slowly - but it worked fine

- the next few times it works much better, but there is a distinct difference to the sound / tone of the eject action compared to the original gears which I still have in 3 of my Mac Pluses - have vide of a side by side comparison which if anyone is interested I'll quickly edit & upload

I think that replacing the broken gear with a metal gear would just 'move the problem on' to the next gear in the assembly, so I wouldn't advocate this. My view is that in a 'friction fight' between a metal gear and a plastic one, the plastic one will lose every time  I'd rather than if a part shears due to sticky grease, then at least let it be the one where you can source a replacement...

cheers

JJD

P.S. I really appreciated your video on YouTube of the floppy clean & service - so thanks again for that. Having done a few now I've got this process down to about 30-40 mins.

One thought / question though - other than IPA which I use does anyone use any other solvents to clean the steel frame/chassis parts? I've experimented with Xylene (yes it's bad for you but I wear protection!) and it cuts through grease & muck like magic, leaving sparkly clean steel... A tiny amount on a toothbrush is all it takes. Can go in with a swab and IPA for the finer parts after that.

 

[JDW]

@jjclay

I’m glad my lube video was a help to you. I would certainly appreciate having a look at your video!

I am curious about the grease or oil on those gears. A lot of people use lithium grease when lubing drive metal parts, and from what I understand the original grease was also lithium grease, but lithium grease damages plastics over time. So was that really used inside that gearbox? If not, what was used? I also assumed that the oil or grease was used on the top, flat part of the gears as opposed to the teeth, right?

 

[LaPorta]

I discovered the original grease about two months ago: Molykote EM-10L. It is no longer made by Du Pont, so I contacted their customer support for a suitable replacement. They recommended their EM-30L, which you can get in small jars on Amazon. It has a completely different feel than white lithium, it has very low shear and is very, very smooth between gears. It is made to be used with either plastic or metal, so it won't hurt the plastic at all. The bunch of drives I have used it on recently have all gotten back to "sounding" normal.

Also, from what I can tell the grease was applied to both sides of the gears sparingly, but not on the teeth. Also, an oil of some kind was applied to the actual metal motor gear. I have a video as well showing how I work on these drives (not knocking anyone elses).

 

[JDW]

I discovered the original grease about two months ago: Molykote EM-10L. It is no longer made by Du Pont, so I contacted their customer support for a suitable replacement. They recommended their EM-30L, which you can get in small jars on Amazon. It has a completely different feel than white lithium, it has very low shear and is very, very smooth between gears. It is made to be used with either plastic or metal, so it won't hurt the plastic at all. The bunch of drives I have used it on recently have all gotten back to "sounding" normal.

Not available in "small jars" on Amazon Japan though. :-(  It is sold, but only in paint bucket size tubs for about US$100 equivalent.

But the bigger question in my mind is, what's the difference between that EM-30L and White Silicone Grease?  Both play well with plastics.  And the fact is, I have the while silicone grease but I don't have the EM-30L.  I also have silicone oil.

 

[LaPorta]

Molykote is molybdenum based, not silicone based. Other than that, I am not a chemist, and cannot tell you the specifics of either. All I know is that it is what was originally used, and works incredibly well with the drives.

Here is some in the US store:

https://www.amazon.com/dp/B00B51C76I/ref=dp_cerb_1

The stuff I purchased is now out of stock. I have a feeling that these companies take the huge cans of it and part it out to regular people like us.

 

[JDW]

Molykote is molybdenum based, not silicone based. Other than that, I am not a chemist, and cannot tell you the specifics of either. All I know is that it is what was originally used, and works incredibly well with the drives.

Well, it's impossible for me to buy Molykote here in Japan insofar as I am not going to buy a $100 bucket of the stuff to satisfy my curiosity.  Maybe someone will donate a jar to my YouTube channel one day for me to make a detailed comparison because I am curious about the difference with my white silicone grease.  If I had a million subscribers like the 8-bit guy I'd probably have the cash to just buy that $100 bucket, but that's not my situation right now.  In fact, I'm partially living off savings things are so bad.

Anyway, after reading the responses here and on vintage Mac FaceBook groups, I decided to buy 4pcs of the PMMA molded gear from the guy in Italy.  I told him I would probably show them in a video on my YouTube channel.  Hopefully silly Corona won't delay the package!  (UPDATE: EBAY says a June 24th arrival. :-(  )

Right now, I have an 800K drive I am in the middle of shooting a recapping video of.  During my testing the drive works well except for ejection.  Sometimes ejection works but other times not.  Yes, I have fully lubed the drive with Silicone grease and Silicone oil.  The small plastic gear is stock but fine, so it must be something else.  I've not added any grease or oil in that gearbox though.  Not sure if that is the source of the problem.  Any thoughts?

 

[LaPorta]

I accidentally burned out a diode on the eject circuit once...look for any shorted/open components traces From

the motor signal Line.

 

[JDW]

I accidentally burned out a diode on the eject circuit once...look for any shorted/open components traces From

the motor signal Line.

But if a component was shorted and therefore burned and destroyed, the ejection should stop working completely.  In my case, it works sometimes and other times not.  I am basically trying to figure out why.

 

[dzog]

Hopefully silly Corona won't delay the package!  (UPDATE: EBAY says a June 24th arrival. :-(  )

I bought a couple of big box games from somebody in Australia who shipped them out on April 14th. The package just entered the U.S. this week. 

 

[JDW]

I bought a couple of big box games from somebody in Australia who shipped them out on April 14th. The package just entered the U.S. this week. 

Australians have it all together.  Europeans on the other hand, well...

 

[dzog]

My estimated delivery date was "Mon, Apr 27 - Wed, May 06"  

I think it will finally arrive on Saturday, if USPS is to be believed!

 

[jjclay]

Good luck with the deliveries! I still seem to be getting stuff delivered from the US, mainland Europe and China OK - but a card from the in-laws in Australia was 2 months late (yes I'm an Aussie, just in 'Europe' - or not as Brexit suggest...). Australia Post & many other postal/delivery companies often hitch a ride on regular passenger flights and with almost all of those grounded, so has a lot of mail.

JDW I've just ordered a small tin of EM-30L off a UK seller - was only £4. I'll pick another one up for you and test the postal services in your direction! PM me for details so I can post it on...

Perhaps it's lack of lubrication in the "gearbox" itself? Did you put any of your silicone oil/grease in there?

I use white lithium grease on metal-metal parts, but haven't put anything in the gearbox yet - maybe that's the root cause of the different pitch & not the plastic gear?

I'll wait until the EM-30L arrives and clean out another Sony 800k (Mac portable needs its cleaned!) so I'll add that to the side by side comparison.

JJD

 

[JDW]

@jjclay

Thank you for your kind offer!  It is truly unfortunate that EM-30L is not sold here in Japan.  You might want to check with your local post office to see if they will even allow you to ship it.  Post offices around the globe have gone made in restricting things they deem "dangerous."  Here in Japan perfume is classified as a "dangerous good."  Check this out:

https://www.post.japanpost.jp/int/use/restriction/airmail/index_en.html

If your post office won't let you ship it, I might bite the bullet and buy some rather expensive (here in Japan) Super Lube 21030 grease which has PTFE (Teflon).  It seems to be silicone based which means safe for plastics.  Until now, I've been using normal silicone grease and silicone oil without any PTFE in it.  Maybe the PTFE makes a difference?  Even so, the EM-30L doesn't have PTFE in it.  Hmmm...

I did not put any grease in the gearbox mainly because I can only figure out how to remove the yellowed gear and the white gear that sits atop it.  But there are two more gears that need to be removed.  How do we safely remove the biggest white gear with the little metal piece attached to it (the gear that actually hits the sliding tray and ejects the disks)?  All gears would need to be removed, cleaned and re-lubed, not just one or two.

 

[jjclay]

Hi JDW

I'm sure it'll ship fine at this end, and will mark it appropriately so it travels as reliably as possible.

Looks like I'd bought the last two from this ebay reseller in the UK - see listing here: https://www.ebay.co.uk/itm/372940190399.

Yes, they buy a big 1kg tin and part it out into smaller tins.

There is another selling doing the same but he's asking £10/tin instead of £4: https://www.ebay.co.uk/itm/Dow-Corning-Molykote-Em-30l-Grease-for-audio-equipment-UK-Seller-100-Genuine/192930439743?hash=item2ceb8ce23f:g:swgAAOSwMmhedf1F, and I think he's just about fully sold out his big tin too...

One of the claims for this grease is that it is "long life", which is reassuring. Don't want anything that'll dry out after just a few years.

I removed a few gears simply by gently levering them up - I think the gears were held onto their spindles with just a friction fit (apart from the main metal gear which is fixed to the motor shaft). The next floppy drive I service (later this week, after I get the EM-30L probably on Wed) will get a "gearbox service and lube" too and I'll share the results - I'm expecting quieter running with less strain on the motor & gears  ;-)

JJD

 

[JDW]

@jjclay

I too thought the gears might just pull out, but I could only get the little yellow gear and the white one above it out by gently pulling.  I didn't try to apply too much pressure to the other two bigger gears for fear of breaking them, so I look forward to hear the technique you employ on the next drive you service.  

I will PM you my address.

 

[LaPorta]

Here is the address of my video:

In the latter segment, I discuss and show you how to disassemble all of those motor parts, and pitfalls to avoid.

 

[JDW]

@LaPorta

Thank you.  I just finished watching the entire video.

You mentioned that you have broken off the two little plastic tabs that secure the metal cover underneath the gear box in the past.  I am curious as to your exact method of repair since I have the same problem.

Right now, I have a couple dabs of hot glue over the broken tap stubs, which surprisingly is holding it in place well after a couple days of testing.  But with all the oils and grease in that area, I expect that hot glue won't last long term.  So I purchased some J-B Weld (the original stuff that hardens like a rock and takes 24 hours to cure).  I've not yet applied it (because it won't arrive until Friday), but supposedly J-B Weld will bond metal to ABS or PC plastic -- I assume this black plastic is ABS.  My intent is to put a dab of epoxy over the location of those two broken tabs (after my cleaning and lube of the gearbox is finished).  The amount of epoxy I intend to use would be small enough to where I hopefully could break it off in the future (should another lube job be necessary 10 years or so hence), but yet enough epoxy to be adequately strong to hold down that plate for many years, should I decide to leave that gearbox untouched.  Even so, hearing how you repaired yours (with 2 broken tabs) would be informative.  One guy on our vintage Mac FaceBook group suggesting drilling and using wire (where to drill and how to use wire, I don't know), but I really don't want to do that.  Epoxy seems like a smarter idea to me.

@jjclay

Thank you again for your extreme kindness in mailing me a small tub of EM-30L.  Your name will be honored in my next video!