Problem with clamp to regulate the focus tension

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ivangallego24
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Problem with clamp to regulate the focus tension

#1 Post by ivangallego24 » Tue Jun 25, 2019 12:39 pm

My problem is that piece that came with the microscope to tighten or loosen the tension of the macro focus broke, and I would like to know how I can create another similar one that will serve me equally

apochronaut
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Re: Problem with clamp to regulate the focus tension

#2 Post by apochronaut » Tue Jun 25, 2019 12:59 pm

A picture would help. I can't recall the type of microscope you have.

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ivangallego24
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Re: Problem with clamp to regulate the focus tension

#3 Post by ivangallego24 » Tue Jun 25, 2019 1:00 pm

IMG_20190625_144300-compressor_opt.jpg
IMG_20190625_144300-compressor_opt.jpg (24.32 KiB) Viewed 3174 times
IMG_20190625_144235-compressor_opt.jpg
IMG_20190625_144235-compressor_opt.jpg (27.9 KiB) Viewed 3177 times
The attachment IMG_20190625_144235-compressor_opt.jpg is no longer available

apochronaut
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Re: Problem with clamp to regulate the focus tension

#4 Post by apochronaut » Tue Jun 25, 2019 1:12 pm

This appears to be a lever that controls a clutching mechanism, correct?

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ivangallego24
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Re: Problem with clamp to regulate the focus tension

#5 Post by ivangallego24 » Tue Jun 25, 2019 1:23 pm

Yes

apochronaut
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Re: Problem with clamp to regulate the focus tension

#6 Post by apochronaut » Tue Jun 25, 2019 2:14 pm

It has come off of the small shaft on which it rotates or the shaft has broken. Which is it?

MicroBob
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Re: Problem with clamp to regulate the focus tension

#7 Post by MicroBob » Tue Jun 25, 2019 2:50 pm

Hi Ivan,
to me this looks like a hook wrench: https://www.google.com/search?q=hook+wrench
Am I right and the little hook broke of?

In this case I would take a piece of aluminium sheet metal, put the old key on top, trace the contour with a felt pen, add the hook and saw and file it out. 1,5mm or 2mm would probably be sufficient, the maximum would depend on the space you have.

Bob

apochronaut
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Re: Problem with clamp to regulate the focus tension

#8 Post by apochronaut » Tue Jun 25, 2019 3:42 pm

In the last picture the end can be seen protruding just past the left hand knob, still sitting in the chuck nut.

Roldorf
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Re: Problem with clamp to regulate the focus tension

#9 Post by Roldorf » Tue Jun 25, 2019 4:44 pm

Yes commonly called a 'C' spanner. Doesn't need to be left on the nut after it is adjusted for tension, as it only gets in the way. Bicycles use a similar spanner for the pedal crank nut, but you wouldn't leave them on when you ride it.
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MichaelG.
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Re: Problem with clamp to regulate the focus tension

#10 Post by MichaelG. » Tue Jun 25, 2019 5:22 pm

https://micro-science.co.uk/iscope-instruction-manual/

... From which I have borrowed this image:
Credit: iScope Instruction Manual
Credit: iScope Instruction Manual
IMG_3076.JPG (42.34 KiB) Viewed 3147 times
Probably the first plastic c-spanner I've ever seen.

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PeteM
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Re: Problem with clamp to regulate the focus tension

#11 Post by PeteM » Tue Jun 25, 2019 6:01 pm

If you have a friend with a shop, it shouldn't be hard to reproduce the spanner. The pin could be either a roll pin or a dowel pin in a press fit hole. The body cut be band sawn out of flat stock (say, aluminum) and sanded a bit to remove sharp edges. One could likely also cut and file the pin feature.

It could also be cut off from an appropriate large ID tube like a thin slice of bread. Drill a hole for the pin and split the ring. Just leaving the pin extending out the other side should give enough grip for adjustment - likely no need to weld or braze on a handle.

Commercial ones can also be bought, but would likely have to be ground down a bit thinner.

Given how flimsy this looks - perhaps intended to avoid over-tightening (or more likely reduce costs) -- the manufacturer likely sells spares?

You might also try finding a close-fitting rod or pin punch. If the hole is deep enough and the clutch disk easily moved, you might get a satisfactory adjustment that way and then leave it alone?

Might also be a pair of jar-opening pliers you could sand/grind/file thin enough and modify (either by adding a pin or adding rubber to avoid marring the adjustment ring).

Hobbyst46
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Re: Problem with clamp to regulate the focus tension

#12 Post by Hobbyst46 » Tue Jun 25, 2019 7:29 pm

A perhaps simple DIY tool: find a long thin metal rod of the same diameter as the C spanner (roughly). With two pairs of pliers, bend the rod until it reaches the form of a C spanner, including the handle. Think of some of the cheapest hacksaws - the small ones, that take blades of 15-20cm, the frame has been formed by bending a wire.
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