Black rubber monitor feet / rollers

Started by pl212, November 07, 2011, 02:33:02 am

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Rob Blessin Black Hole

As most of the 4000 feet have melted long ago , so the easiest approach may be to use the inner spindle of the 4000 and the exterior of the 4000A .  Are you thinking about creating a mold or 3d printable replacement.
Rob Blessin President computerpowwow ebay
303-741-9998 Serving the NeXT Community  since 2/9/93


As there are no master samples, it's necessary to create one, I'm working on the CAD. I already made a CAD model for the 4000A, I'm now waiting to get a N4000 display for measuring the main dimensions of the plastic spindle.
Idea is then to 3D print a master sample for checking fit and form. Once validated, next step will be making a mould for liquid rubber casting, either out of silicone rubber or directly out of solid blocks of aluminum or plastic (CNC).
As for the material, after some preliminary search, I've found some options with polyurethane rubbers for casting. Picking the right final hardness will be difficult, but I assume shore A 60 to 80 should be fine (more or less like a tire tread).
Long and complex project, but I want to give it a try.


Some updates on this investigation. Today I finally received the N4000 display I was waiting for. Nice unit, crisp and bright CRT. The paint of the steel base is bubbling here and there but it's overall OK. The rubber rollers are gone, sticky and soft like bitumen. I managed to remove one and to disassemble and clean the spindle.
First finding: the rubber roller of the N4000A serie is not compatible, i.e. you cannot fit N4000A feet on N4000 spindle, not even the inner diameter is the same. Probably, you all knew that already.
Outer dimensions seem to be compatible, though.
So, I have no clue if N4000A rubber rollers are still available in some quantity, but for sure it would be much easier and way cheaper to 3D print / CNC a "hybrid" spindle (compatible with N4000 base and N4000A rubber) rather than casting new rubber...


April 23, 2019, 07:30:25 am #18 Last Edit: May 12, 2019, 05:01:56 pm by paolo.bertolo
Hi Guys,

latest updates on this project.

After some additional trials, I've finally nailed the recipe (mix of different compounds), the final hardness is now definitely OK.

Additionally, I've put in the process a small vacuum chamber for "degassing" the mix before pouring it in the mould, this helps with the elimination of most of small air bubbles that may remain entrapped during the mixing process.

The final aspect of the roller with the graining coming from the mould is totally consistent, so one could even keep it "as is" right off the mould.
However, some sanding with a very fine grit paper and the aspect gets much closer to the matte finish of the original rollers.

It's a matter of tastes, but to my opinion - as we're speaking about a "replica" - it looks nice in both finishing levels.

Anyhow, from my angle this project is now over, I got what I was looking for, it kept me busy for a while, I learnt something new, I'm not planning to further develop it. Besides, it costed me already serious money and any improvement would require additional expenditure.

Now, I have raw chemicals (which have limited shelf life) for not so many more parts (my guess is between 10 to 15 pieces, including scrap rate, say 6-8 sets max), I will make pieces until chemicals and disposables will last.

Unfortunately, at this moment I can't commit to make more, as it's a very time consuming (and expensive) process (I can only work on this over weekends, and each set keeps me busy for hours...).

I attach some pics, as in the transition to the new forums (cool!) something went lost.
You cannot see attachments on this board.


Final result, I'm OK with it!


Very good Paolo, a perfect result imho  8)



Paolo, I am very excited to hear about all of your progress on this project! (I say "hear" because I can't see any photos that had previously been attached...).

I'd really like to get a hold of a set myself, but it sounds like they're a ton of work to produce. Of course I'd like some of yours if they are available and you've found time to make some more, but more likely I ask, would you be willing to share the 3D CAD model?

3D printing might be an option with some of the new rubbery materials that are now available. I'd be interested in trying that out, and it could be a sustainable source for folks that end up needing them in the future.

Also, a few years ago I had the opportunity to visit St. Gallen. Happy to meet someone from there!


Hi All,

I finally  finished the moulding of all rollers I could make with the available consumable materials.
Eventually, I have a total of 20 sets (40 pieces), which took me busy over the weekends for one month (in this corner of the world, it's been horribly rainy).
Considering the very relevant effort in terms of both money and time (each single piece takes between 1.5 and 2 hours), for sure I'm not planning to make more.
I tried to create an ad on eBay, but it's too complex, especially as I'm currently based in Poland and Polish is not my strongest asset...
So, for the moment I just desist and if anyone is interested I will take direct orders (please PM me or contact me at paolo and then a dot, then bertolo, then an "at", and then gmail, a dot again, and then com).
Asking price is 40 € (Euro) per set (2 rollers), plus shipment and - in case - taxes.
I'm not able to quantify shipment costs, but in case it will be a small padded envelope, so I'm not expecting much. Case by case, I will verify with the local post office and will inform before the payment is finalised.
I'm open to consider different conditions for multiple orders, my wish is just to see as many N4000 displays as possible finally back in a close-to-original cosmetic shape.
Below some more notes I have prepared for the eBay ad.

"Set of 2 rubber rollers for NeXT MegaPixel Display N4000.
These are replica rollers, as original spares are no longer available.
They are made with formulated polyurethane compound, final shore hardness approx 75 shore A.
Please note that the inner spindle is different between N4000 and N4000A series, so the rollers will not fit on N4000A displays.
For sale are off-mould pieces, on purpose not including any additional finishing, as it is possible to further adjust the final optical finish depending on personal tastes.
Off mould surface finish is slightly coarse and shiny, but consistent.
Sanding (at own risk) the outer surface with fine grit paper will give the rollers an even and matt look.
Due to the hobbyist nature of the production, they are sold as they are, no return accepted."

Rob Blessin Black Hole

Hello Paolo: I sent you a PM , obviously I would be happy to buy a few sets and also distribute them here in the US and I have some nice 4000 monitors that need feet. Lets make a deal. Best Regards Rob Blessin
Rob Blessin President computerpowwow ebay
303-741-9998 Serving the NeXT Community  since 2/9/93


I got my rollers in from Paolo today. I am beyond impressed! I 100% would believe these are factory parts. The rubber has a great feel and the texture looks great.


Quote from: barcher174 on June 18, 2019, 03:55:58 amI got my rollers in from Paolo today. I am beyond impressed!

Thanks for your feedback, Brian!
I'm really glad you are happy with the result!