Sourcing non-printed parts

Lots of people have found different places to source the fastenings (M3 nuts and bolts, for example) in different countries, as well as different places to get hold of the optical parts. This thread tries to be a place where we can collect sourcing information. We should probably tidy it up and put it into the handbook, but that’s harder for lots of people to edit and discuss, so let’s share information here first.

There is currently a page in the handbook for sourcing non-printed parts, but it’s quite sparse.

Some relevant Issues:

That is a good idea. I spent a lot of time and money on sourcing the parts. Ended up buying screws etc on Amazon.

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I’ve finally ordered some stock of screws and o rings, so hopefully very soon OpenFlexure Industries will be able to offer kits (in the UK at least) of the non-printed stuff. I’m just waiting on condenser lenses and LED cables now. If you didn’t mind sharing what you bought and from where, I’m sure it would be really useful to others here.

Here is my sourcing and I will update this later :

PMMA LED lens Diameter 13mm Height 5.0mm Plano Convex (Aliexpress) - not tested yet - 0.23$/pc (waiting delivery)

20pcs 342 (ODThickness) Green Fluorine Rubber O Ring (Aliexpress) - Great and do the job well - 6.8$ 20 pcs

Tube lens Diameter 12.7MM Focal Length 50MM Achromatic Double Lens (Aliexpress) - Not tested yet (waiting delivery) - I bought mine 18$/pc but price fluctuate and tooday the lens is 25$/pc
Tube lens on Thorlab direct link - work great - 50€/pc (but in UK and fast delivery in France)

Beam slitter
From Comar, but didnt order yet here the link I was thinking of [25 BV 16] 25x16mm 450-700nm (visible) 50% - £22.75
From Aliexpress : Just a search Link

For nuts and screws in France I use for years now Bricovis

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Hi everybody,

It’s a great idea because when you begin the build you are a little lost, even more when you are a complete beginner in optics domain (I build the microscope for my daughter).
I’m in France.

I have ordered the Tube lens from Thorlabs as indicated (but they ask a lot of official papers to be filled). Very expensive with VAT + shipping : 80€

For the Nitrile rubbers, I have found these ones on Amazon UK (pack of 50) :
I hope that’s the good ones.

Maybe a group purchase would help to get some reduced prices. Kits would also be very helpful.


I also paid about 80 euro for the tube lens from Thorlabs. Was offered 200 pcs for 3 USD/pcs from a Chinese producer on Alibaba. So it looks like significant savings should be possible through a group purchase.

Is $3/piece for achromatic lenses, or just planoconvex singlets? I think achromats probably are worth spending a little more on, because the early versions of the microscope definitely did suffer from using singlet lenses. Of course, everyone’s price/quality tradeoff will be slightly different…

Not sure, I just sent over the specifications as it is on the website but did not consider it seriously as I do not need 200 pcs for the moment. I just notice that it would be much cheaper than the one I bought from Thorslab. But I agree, it might be worth paying more for better quality.

I too am also still waiting on 20 x pmma lens 5mm from Ali Express :frowning: I fear a trade war between US and China has my order siting in a container ship somewhere.

I have been able to take tiled picture sets and use Microsoft Image Composite Editor to stitch them together on the lower resolution optics, my understanding is that this PMMA lens will help add to the contrast and potentially have better quality stitched together pictures. The white LED alone seems to have been enough to lighten the picture. I am really curious if I am even missing out on some quality without this lens.

Given that we now seem to have a supply chain problem with the PMMA objective lenses, I am interested in finding an alternative. Adafruit has much larger 40mm lenses that just seems crazy big. Perhaps 2 LEDs and/or a wider hole?

2 LEDs is tricky, because it means the illumination isn’t uniform any more; arranging several LEDs to cover a wider area (or even using a matrix of LEDs like Adafruit sell) is an option, and indeed people have published some cool results making synthetic images by illuminating one LED at a time and combining all the resulting images.

The lens in the illumination does two important things:

  1. it concentrates the light from the LED into an area just a little bit bigger than the area you’re imaging, which means
    a. you improve contrast because there’s less light hitting the objective from outside the area you’re imaging
    b. you improve brightness because you’re not wasting much light
  2. It increases the numerical aperture of the illumination, i.e. the light converges on the imaging area from a larger range of angles.

The lens means you’re illuminating an area around 1mm across - so it’s concentrating the light by a factor of hundreds or more. So just adding a few more LEDs will improve brightness but not by anywhere near as much. However, if you have a fairly bright LED, brightness is often not what limits you, it’s stray light (which you really can’t fix without a lens) and numerical aperture. You can fix the numerical aperture problem by using a diffuser instead of a lens - try sticking some white electrical tape over the aperture where the lens should go. It will hurt brightness even more, but should improve image quality if you have a bright enough LED to start with. You’ll want the condenser fairly close to the sample.

I just found this one which seems to be the same tube lens but cheaper,searchweb201602_,searchweb201603_