Poor man’s "Kohler" illumination

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MichaelG.
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Re: Poor man’s "Kohler" illumination

#31 Post by MichaelG. » Sat Apr 01, 2023 11:41 am

Phill Brown wrote:
Sat Apr 01, 2023 11:13 am
I could get one and make things from old Kohler bottles.
:lol: MichaelG.

.
P.S. __ I see you are in Devon, Phill

I suggest you have a look at the top section of the 1litre Cravendale Milk bottles
… Part that off in the lathe and you’re almost there
Too many 'projects'

Chas
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Re: Poor man’s "Kohler" illumination

#32 Post by Chas » Sat Apr 01, 2023 11:51 am

it's better that way for my patience levels.
I haven't tried aligning the mirror in a system70, but somehow this drawing comes to mind, when I contemplate it:
HR 2.jpg
HR 2.jpg (47.09 KiB) Viewed 1203 times

Phill Brown
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Re: Poor man’s "Kohler" illumination

#33 Post by Phill Brown » Sat Apr 01, 2023 12:58 pm

The top of the illustration is missing where the image of the filament is projected on the ceiling, also missing the soldering iron.

MichaelG.
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Location: North Wales

Re: Poor man’s "Kohler" illumination

#34 Post by MichaelG. » Sat Apr 01, 2023 8:13 pm

Phill Brown wrote:
Sat Apr 01, 2023 9:47 am
IMG-20230401-WA0003.jpg
Part of the problem with Kohler is it's not competitive to produce.
I was wondering about getting a 3D printer.
.
It doesn’t need to be that complicated, Phill
… I think Watson was just going through a “too clever by half” period when they designed the System 70

MichaelG.
Too many 'projects'

Phill Brown
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Location: Devon UK.

Re: Poor man’s "Kohler" illumination

#35 Post by Phill Brown » Sat Apr 01, 2023 9:04 pm

That's the Hilux.
Maybe not the best beginners project,a little daunting and a lot heavier than it looks when complete, built-in transformer is substantial.
There are also 2 filters in the field lens for UV &IR.
The standard 6v 30w Kohler is simplified.
I have stock of the first surface mirror, they are all past their best.
They used a modified B15D 15v bulb in production with a fixed collar to align the square filament.
Making a replacement for that is not as easy as it could be.

MichaelG.
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Location: North Wales

Re: Poor man’s "Kohler" illumination

#36 Post by MichaelG. » Sat Apr 01, 2023 9:39 pm

Phill Brown wrote:
Sat Apr 01, 2023 9:04 pm
That's the Hilux.
Sorry for generalising, Phill

So far as I was aware, Hilux is part of System 70

My real point was that many features of that system seem to be ‘novel’
[sometimes, it would appear, just for the sake of it]

I remember my surprise when I dismantled an XY stage and found the strips of adhesive PTFE tape.

MichaelG.
Too many 'projects'

Phill Brown
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Joined: Mon May 24, 2021 1:19 pm
Location: Devon UK.

Re: Poor man’s "Kohler" illumination

#37 Post by Phill Brown » Sat Apr 01, 2023 10:56 pm

System 70 is a modular concept from '65 ish.
The stand had a choice of bases.
Bright field. 6v 15w
Bright field with intensifier,a swing in mirror under the filament. 6v 15w
Kohler, with high/low lens. 6v 30w.
Hilux with 12v 100w
Swing in diffuser and high/low lens.
If they'd known they wouldn't last maybe they wouldn't have made their microscopes to last either.

Chas
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Re: Poor man’s "Kohler" illumination

#38 Post by Chas » Sun Apr 02, 2023 9:51 am

Phill, what do you suggest is a good way of going about mirror alignment for a 'Kohler, with high/low lens. 6v 30w'
I get the feeling that you might have tangled with more than one of them !

Phill Brown
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Location: Devon UK.

Re: Poor man’s "Kohler" illumination

#39 Post by Phill Brown » Sun Apr 02, 2023 11:04 am

Not saying it's the right way but.
If the filament is fixed and the field lens is fixed,
The objective is fixed so with the condenser out of the equation the filament needs to be centered through the eyepiece, with the Kohler iris fixed it's possible to narrow down some more, with everything central add the condenser and centre that, focus on the Kohler iris to Sharp edge, I use the x40 as it tends to get more critical but probably should be 100 oiled.
Centre the condenser iris with 4 grub screws.
Last part is to get the best picture of the filament on the condenser iris.
I choose to only do one operation at a time but if it's all messed up the fixed reference points are what I work from.
I have also put the field lens in the lathe and put small circles on with a fine indelible, picking up the dead centre can speed things up.
I have dial guage down to microns for centering.
The eyepiece is usually fixed so if using a camera,dead centre is on the screen.
A sheet of paper on the frame above the objective can show if you have a good light path,
A sheet of photo paper on the ceiling is not a joke,it all helps when I don't really know what I'm doing.
If I remember correctly the low/high should both be in focus, just manified.
Also from memory the filament is focused on the Kohler iris but it's been awhile.
Edit. I should add, with microsystem 70
The field iris and the objective nose are pinned with alignment dowels so they are the reference points.
When possible measure the original thickness of the mirror and mount and fit correct thickness cork shims so the focal length is unchanged.
A phase telescope is definitely worth having, not sure if it can be done without.

Chas
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Re: Poor man’s "Kohler" illumination

#40 Post by Chas » Sun Apr 02, 2023 1:33 pm

Thanks, I took the mirror with its support frame out give the mirror a gentle rinse :-(
The photo of your Hilux is very helpful as I handn't considered adjusting the mirror screws with the microscope lying on its side and with its base removed.
:-)

Phill Brown
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Joined: Mon May 24, 2021 1:19 pm
Location: Devon UK.

Re: Poor man’s "Kohler" illumination

#41 Post by Phill Brown » Sun Apr 02, 2023 2:18 pm

No worries Chas.
A circle of white paper on the iris will help to focus things, can mark the centre.
It's good to mark anything with slots in a couple places with a Sharp scriber.
I fit a Hosobuchi OP-2118 6v 30w to the Kohler base.

Edit. Lamps2udirect £20 Inc postage for UK..

It's probably what the original lamp was intended to be.
With a lathe it's easy to make a collar, the pins where filed off the original also, soldering the collar on precisely with the filament centered and in focus is the challenge. Collet chuck is helpful but there was probably a jig and a projector set up at Watson.

Chas
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Joined: Tue Jan 19, 2021 3:11 pm

Re: Poor man’s "Kohler" illumination

#42 Post by Chas » Mon Apr 03, 2023 7:24 pm

Thanks Phill, I think I will get one.
I spent a few hours over the weekend trying out ZodiakPhoto's field iris placed over an LED diffuse illuminator (using an iris rather than fixed stops) quite an interesting exercise ... the (Beck) abbe condenser threw out some really vivid blue backgrounds and the defectiveness of the condenser was very clear when the iris got down to one or two mm. Much as Conrad Beck described in his Book 2 (*Below) . I cant say that I saw a reduction in glare or improved contrast that was of a different quality to that that comes from shutting down the condenser iris, (indeed I found it hard to fill the back of the objective with the condenser iris fully open but the field diaphragm closed ), but I think I should try it again with a better condenser.

*Here https://archive.org/details/microscope0 ... 4/mode/2up

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