Nylon gear in eject motor(800K)

[bunnspecial]

I'm on my second broken gear in as many weeks on 800K floppy drives.

The first was on a 512Ke that I sold last week(I had to do a last minute swap from my spare SE when I realized it was dead) while I found the second this evening in a Mac Plus I was given today.

Basically, what I'm finding is that the smallest nylon gear in the eject motor assembly-the one that engages the metal pinion on the motor-seems to shed its teeth when the eject mechanism and/or motor gets gummy(I suppose it's the weakest link). Of course, I always service the eject mechanism, but sometimes I end up being too late to save the motor.

Short of buying a replacement drive, is there a source for these drive gears? I've hunted on Ebay and am coming up short. I'd prefer to fix the drives I have, although admittedly I wouldn't want to dump a bunch of money on one small replacement part when complete working drives are $30-40.

I'm also considering taking a dead gear over to the engineering school at my university and seeing if they'd want to take on reconstructing it in CAD and then 3D printing it, although I don't know how feasible this would be.

Any thoughts on any of the above?

 

[MacTech68]

There's a shapeways 3D printed version available. I haven't used them as yet. They used to offer just the gear that seems to break the most, but now they only seem to offer the whole gear set.

http://www.shapeways.com/product/3F...oppy-drives?li=user-profile&optionId=42950835


There's also a member here @mosaiko who makes them themselves and may be able to offer them for a fee.


------EDIT 2016-01-21-----
Seems the older listing for the single gear x4 is back. See post below.

 

[bunnspecial]

Thanks-I'll order one and give it a try.

I wish I could just get the first gear. That's the only broken one I've run across, and it seems to me like it's the most likely to break since it meshes with the metal pinion on the motor.

I'll contact mosaiko also.

 

[mosaiko]

Thanks-I'll order one and give it a try.

I wish I could just get the first gear. That's the only broken one I've run across, and it seems to me like it's the most likely to break since it meshes with the metal pinion on the motor.

I'll contact mosaiko also.

Answered now by PM ^_^ ; the gear i reproduce are not 3D printed but by a mold with an hard polymer that works for gears like these. This gear need to run with a metal pinion as you know. i've try to break my gears stressing them with the hands and the mechanism a lot and at the end to me are better then the original

 

[bunnspecial]

Answered now by PM ^_^ ; the gear i reproduce are not 3D printed but by a mold with an hard polymer that works for gears like these. This gear need to run with a metal pinion as you know. i've try to break my gears stressing them with the hands and the mechanism a lot and at the end to me are better then the original

And thanks to Mosaiko I now have five drive gears on the way

I did order the set from Shapeways so I will evaluate it also and see, although I like the idea of a hard polymer.

 

[bunnspecial]

Bad news on the shapeways product-the center holes are too small, and the eject mechanism motor is not able to overcome the resistance imposed by this(the gear would barely fit over the shaft).

Especially given the price, I'm very disappointed and am requesting a return and refund-especially in light of the fact that mosaiko's gear is much less expensive and hopefully will actually fit correctly(I'm sure it will).

 

[MacTech68]

Crap - I seem to recall the version 1 of just the gear that breaks had a note about needing to ream the hole out a little.

And what do you know; now that I check again, the other listing is back. It says it's V2 with a redesigned hole. Even though it says it was updated October 31st 2015.

--face palm--

I SWEAR it wasn't there when I checked earlier this month - damn it.

http://www.shapeways.com/product/M84R343FR/gear-for-macintosh-512k-vintage-floppy-drive-eject


I really hope you can come to a satisfactory arrangement with the vendor.

 

[bunnspecial]

Shapeways is refunding my purchase price and told me to keep it. That means that I'm going to play with it and will likely ream the hole out larger.

I know this isn't exactly precision work, but I'm still going to get my Seitz watch jewel press out and use it to ream the hole-I have a good chance of keeping it concentric and avoid going TOO big by doing that. The advantage to using the Seitz reamers is that they're designed to make a very precise diameter round hole with perfectly parallel sides.

Of course, there's always also the standard pentagonal cutting broach-I might have one in close to a correct size.

 

[bunnspecial]

I finally spent some time time last night working on the gear.

First, I measured the diameter of the post on which the gear rides.

As you can see, it measured ~1.985mm, which gave me a guide for how big the hole in the center needed to be.

I went to my reamer set.

Ideally, I would have liked something like a 2.05mm reamer, although as you can see I don't really have anything close to that. Seitz reamers are always .01mm smaller than the jewel they are designed to work with(to create a tight interference fit), which is why they are sized as such. The 199 reamer(1.99mm) passed cleanly through the hole in the gear-meaning that I needed a larger hole than that.

Unfortunately, the next option up was the 219, which is what I used

The resulting hole was a tiny bit too large and allowed some sideplay of the gear. With that said, these eject motors are not exactly precision devices, and the drive now ejects fine.

 

[maczo]

I owm both gears, and found mosaiko's to be way more accurate. Shapeways' are kind of defective. Will post comparison soon.

EDIT: comparison added!

As you can see, the original is all cracked! Mosaiko is the finest, although the back side is flat (I don't think it's a problem... maybe you can use a plastic ring or something in the center to raise the gear from the base). The Shapeways' seems to be pushing their 3D printing machinery to its limit! All the gears I received from them had a defective tooth (as you can see) and I had to file it. Also I had to enlarge the center hole to fit the shaft.

 

[gnolivos]

Hi all... I am the person who designed the Shapeways replacement 3D printed gears. I am reading the thread here with interest (and somewhat disappointed!) to see how Shapeways sent out clearly a terrible batch of printed gears to this customer. Either they had an issue, or they used the wrong material.

I've sold numerous gears during the past 2 years and can honestly say that while the early versions had too small a whole, the overall quality and detail has been outstanding. And nothing like what the pictures above show. A further revision took care of the orifice size and they do work flawlessly.

Shapeways should have never sent that out that defective gear to a customer. I can tell you without a doubt the gears when printed in their Ultra Detail Frost material is perfectly accurate and detailed. they even have a MORE detailed printout material (more expensive) but that was not even necessary according to my testing samples.

Here are some pictures of the Shapeways gears (attached). I personally sell them through eBay as well, and have had hundreds pass through me from Shapeways and never ever have seen such a terrible gear printout as this customer received.

@bunnspecial, please send me a PM with your address and I will send you 2 free gears at no cost!

 

[Gamer9430]

Hi all... I am the person who designed the Shapeways replacement 3D printed gears. I am reading the thread here with interest (and somewhat disappointed!) to see how Shapeways sent out clearly a terrible batch of printed gears to this customer. Either they had an issue, or they used the wrong material.

I've sold numerous gears during the past 2 years and can honestly say that while the early versions had too small a whole, the overall quality and detail has been outstanding. And nothing like what the pictures above show. A further revision took care of the orifice size and they do work flawlessly.

Shapeways should have never sent that out that defective gear to a customer. I can tell you without a doubt the gears when printed in their Ultra Detail Frost material is perfectly accurate and detailed. they even have a MORE detailed printout material (more expensive) but that was not even necessary according to my testing samples.

Here are some pictures of the Shapeways gears (attached). I personally sell them through eBay as well, and have had hundreds pass through me from Shapeways and never ever have seen such a terrible gear printout as this customer received.

@bunnspecial, please send me a PM with your address and I will send you 2 free gears at no cost!

Can you PM me a link to the eBay post? You're not allowed to share your own eBay links in the threads, but I'm in dire need of these gears.

EDIT: nvm I found it: http://www.ebay.com/itm/Set-of-2-x-...110332?hash=item3d3967d1fc:g:sikAAOSwvgdW4sti

 

[gnolivos]

I have singles, sets of 2, and sets of 4 listed.

Can you PM me a link to the eBay post? You're not allowed to share your own eBay links in the threads, but I'm in dire need of these gears.

EDIT: nvm I found it: http://www.ebay.com/itm/Set-of-2-x-...110332?hash=item3d3967d1fc:g:sikAAOSwvgdW4sti

Can you PM me a link to the eBay post? You're not allowed to share your own eBay links in the threads, but I'm in dire need of these gears.

EDIT: nvm I found it: http://www.ebay.com/itm/Set-of-2-x-...110332?hash=item3d3967d1fc:g:sikAAOSwvgdW4sti

 

[MacTech68]

I have singles, sets of 2, and sets of 4 listed.

On the Australian eBay site, I can only see the set of 4. Is that "by design" or an error?

 

[gnolivos]

I didn't originally consider selling outside of US because of the risk of problems with shipping etc. I ended up deciding to offer the 4xset to make the risk worthwhile.

Sorry about that. I may decide to remove them altogether from international.

On the Australian eBay site, I can only see the set of 4. Is that "by design" or an error?

 

[MacTech68]

I didn't originally consider selling outside of US because of the risk of problems with shipping etc. I ended up deciding to offer the 4xset to make the risk worthwhile.

Sorry about that. I may decide to remove them altogether from international.

No apologies necessary. I understand the logic. Please keep the 4x available for international purchase.

 

[bunnspecial]

I wanted to report that, good to his word, @gonolivos sent me two of his Shapeways eject gears, and for that I'm very appreciative.

I will report back when I've had a chance to install at least one of them.

 

[gnolivos]

Glad you got them. Packaged well so should be intact. Let us know how it goes!

 

[gnolivos]

I wanted to report that, good to his word, @gonolivos sent me two of his Shapeways eject gears, and for that I'm very appreciative.

I will report back when I've had a chance to install at least one of them.

Did you ever install them?