Thinkpads Forum

Hi All

Everyone who owns a 700C will be acutely aware of the issues with the hinges. I'm trying to come up with a way to resolve these issues and make the 700C stable and usable again.

As far as I understand it, there are two issues:

1) The hinges themselves become too stiff
2) The plastic base which the hinges are screwed to, using only 2 screws each side becomes brittle and cracks.

My initial focus is on replacing this piece of plastic which sits across the top of the keyboard section and across the back of the unit.

I acquired this faulty 700C as a machine which I could disassemble to inspect the plastic, which I can show here:















As you can see, it's a reasonably complex piece of plastic and as far as I can tell with various people who have tried to remedy issues with laptop hinges, but I'm wondering if a solid metal piece would be within the realms of possibility? The plastic sections for the hinges to bolt to are very thin, small and I don't think it'll be possible to 'fix' the original piece.

Also this one in the photo is already missing the right side. However I have a second machine which is so far undamaged which I can take apart.

So does anyone have any ideas? A type of 3D printing which would have the strength? Maybe with two metal inserts either side?

Any ideas or thoughts gratefully recieved?

All the best

I tried, in short, for the right side (next to the ps/2 mouse port), there is no room for enhancement. For the left side (next to the fax/modem port), you may do something but it still does not help a lot.
My 2c is to sand it and then apply 3-4 layers of fiberglass mesh with glue. Plus, the hinge stiffness is more important, you should loosen it to a reasonable spot

Hi

The first thing I've figured out is my back section is actually part of the front section, but snapped on the thin sections right and left. However I've now ordered a Bambu H2D with a bunch of accessories and I'm doing a course in Tinkercad. This should optimise protyping with a fast turnaround. I'm going to rebuild the original back section first terminating where mine has snapped as a way to prototype, in PETG and ABS and then incorporate some slide-in spaces for solid metal brackets for both side of the hinges to bolt into. I think with some reinforcing and the plastic base being tensioned by all the parts connected to it, it might work.

The issue with your idea is that a lot of bases have already smashed to pieces and have gone extremely sticky. I think we need to re-think that base, in black.

Obviously the time this takes will be extended by me learning the hard way how this 3D printer will cope with the intricate details of the original plastic base.

I'll come back with progress in the next week or two.

All the best

You have the best 3d printer which supports cf-nylon/cf-petg, so I assume the ultimate solution is to rebuild the whole case. However, that's definitely pricey.
I have a non-working 700 (no c) in bad shape, maybe I can start with that after I wrap up current working of grid 2270.

BTW, we need a dedicated repository for IBM Thinkpad replacement parts, focused strictly on OEM-spec accuracy. Most current models are too "free-style" and only work as a set. We should have them verified to be 100% interchangeable with the original hardware.

Hey

So here is where I'm at. Currently focused on purely the back section, altough the final design will include the whole panel, front and back. I'm almost at 1-1 replica point, and have loosened the hinges back to original specification.

This is Mk6 of the design. My focus next is counter sinking screw points, test-fitting all the original components back to the recreated board and then working out ways to strengthen the hinge mount-points.








I'm using PET-G and a bamboo H2D which is capable of doing the entire top-base.

We do need a repository - it's getting hard to keep up with it all! I think I can build one.

solidpro wrote: ↑

Sat Feb 21, 2026 10:55 pm

We do need a repository - it's getting hard to keep up with it all! I think I can build one.

This is absolutely something I can add to the IBM section on my website.

astral wrote: ↑

Sun Feb 22, 2026 4:09 pm

solidpro wrote: ↑

Sat Feb 21, 2026 10:55 pm

We do need a repository - it's getting hard to keep up with it all! I think I can build one.

This is absolutely something I can add to the IBM section on my website.

Here is something I'll add to when I find things. It's empty right now, but when I get 30 minutes, i'll add all that I have.

https://ret.rocks/index.php/randoms/3d-print-repository

I have all my verified model (.stl) in a google drive folder

https://drive.google.com/drive/folders/ ... sp=sharing

If we all use tinkercad, we may also share the links for remix.

Hey. Thanks for sharing, I'll have a look. I'm currently using Tinkercad and getting OK at all the basics but do find some elements a little too simple, so I might take a course in Fusion. I don't know if you can just buy fusion (was fusion 360) or you need to pay through the nose for some subscription though....

Ok, I'm nearly there. mouse buttons now fully incorporated and working against the keyboard. There really is 10ths of a mm differences going on here. Everything bolts into this top section and functions including the hinges. Next steps are attaching the top and seeing how the current strengthening is working and whether it will close properly, sorting the latching and the attachments to the original base. These designs have moved on a few more steps since the photos were taken with the cut-out for the mouse buttons being cleaner and some other little things....

don't print that flat, hinge part would be easily broken from joint of different layers. try align it diagonally, even for the proof of concept, like 40-50 degrees depending on the supporting.

I've been trying a few different things (which have often since fallen by the wayside) but now what I'm doing is reinforcing both hinge sides with 2.5mm sheet aluminium (which essentially slides into a rectangular hole, but the final design splits into two versions - one with those slots for metal reinforcing but also I'm hoping soon to do a test print in PPS which sets hard like metal. I don't know how many new issues I'm going to have with that, but I have it here ready to dry and then ready to try.....

I'm using an Bambu H2D and would have no idea to 'force' horizonal sections to be printed diagonally - infact that sounds impossible - how would you achieve the diagonal print you're referring to?

Obviously the flat top sections build up in diagonal layers:

before slice and send it to the printer, adjust the angle to 40~50 degrees in the prepare phase. for the model, it allows you to adjust it from 3 different directions, lean it and leave the longer side on the printing plane and general upside down to minimize the support. given a strong enough printing material, i don't think you need more metal for reinforcement

Do you mean before slicing, rotate the model on the plate 45 degrees rather than 90 degrees as in the picture?

correct....https://www.youtube.com/watch?v=7aJ4dDyyf20 FYI

It's almost there. This is a cheap rendition in PLA because I can't currently get more PETG. I'm trying one now in PETG-CF (carbon fibre) but it's thicker and might not come over well. I'm going to also try in PPS tomorrow. Although actually standard PETG does seem to be quite strong enough for the lid opening and closing.

I'm working on some very very fine details - mainly the lid closure catch holes, which are impossible to measure because their inside the plastic.

And in PPS. Hardens like a rock but is too thick and brittle: