Wild M20 Service Manual

[Grahame]

Hi folks,
Does anyone have an M20 service manual you wouldn't mind sharing ?
I have an exploded schematic view but not sure it will help me much.
I need to get to the innards of the stage.
The x axis had some play in it when I bought it.
Now it has so much play that it is a real pain to use.
Hopefully it's not going to be too major a fix (probably famous last words).
Thanks
Grahame

[MichaelG.]

I need to get to the innards of the stage.
The x axis had some play in it when I bought it.
Now it has so much play that it is a real pain to use.
Hopefully it's not going to be too major a fix (probably famous last words).

I think [fear] that you might find this useful, Grahame:
http://www.microscopy-uk.org.uk/mag/ind ... aling.html

MichaelG.

[Grahame]

Thanks Michael,
I've read several times about the plastic gears.
I was hoping that it wouldn't be the cause of this
I had in the back of my mind it may be possible to 3D print a replacement one.
That's out of my depth at present but doesn't mean I can't think of a way to do it.
Ah well of for a good read of your link.
Cheers

[MichaelG.]

I had in the back of my mind it may be possible to 3D print a replacement one.

In which case, you might also find this useful for reference dimensions:
http://www.hbuehrer.ch/Wild-M20-Stage.html
Sorry, I can't be of any practical help at present ... but I will be very interested to see what you find and how you fix it.

Good Luck
MichaelG.

[Grahame]

Hi,
Yes had had a look at that page.
Also looked at Ebay, the prices for a 2nd hand stage are more than I paid for the microscope, then add seriously high freight and 15% GST when it gets here, thats not an option
Cheers

[Grahame]

Update and ideas.

The good news is it's not the plastic gears, they look fine.
I pulled off the side panels beside the x / y stage knobs and realised that if you push the stage right back you can see the whole of the shaft and the bottom of the gears.
This also let me what was causing the problems.
The "direction changer" for want of the correct word that flips when you change the x-axis direction is sluggish to engage.
It's taking around a 180 degree turn of the knob before it flips direction.
Will know more when I pull it apart properly.
Unfortunately won't be for a week or so.

Now for some thoughts.
I went looking for way to get my hands on replacement gears to adapt.
After a bit of thought, I discovered radio controlled car pinion gear, a couple of companies, Tamiya, Robinsons Racing, a few others as well.
Plenty of different gear sizes and tooth numbers.
Most seem to be for 1/8", 3mm shafts, but should be drillable or better putting into a lathe.
Various metals, steel, ali etc.
Possibly adaptable to all sorts of broken scope gears.
Look for a hobby shop in your area.

For the M20 I found some 16 tooth ones that seemed from the measurements I was given would have fitted.
4 of them wouldn't have cost much.
Especially by comparison with a new stage.

[MichaelG.]

The good news is it's not the plastic gears, they look fine.

Wonderful !

MichaelG.

[Grahame]

Just to finish the saga off.
Fixed and working better than since I've had it.
Hardened bits of grease stuck under the "direction changer"
Took the stage of, cleaned and regreased.
Happy it turned out to be an easy fix.

Would still like a service manual if anyone spies one on their travels.

[viktor j nilsson]

Update and ideas.
For the M20 I found some 16 tooth ones that seemed from the measurements I was given would have fitted.
4 of them wouldn't have cost much.
Especially by comparison with a new stage.

Would you mind sharing some links for these gears? I have a spare broken stage that I might wanna fix to keep as a backup (and learning experience). Thanks!

[viktor j nilsson]

...and congrats for getting it to work!

[Grahame]

Hi Viktor,
I's been fun.
These are the 16 tooth that based on the measurements given by the hobby shop I spoke to were the closest I found for the M20

https://www.ebay.com/sch/i.html?LH_CAds ... =&_fosrp=1

The original ones in the M20 stage are 33 tooth.
All 4 on the shafts would need replacing.
Also drilling etc.
Of course not as fine a control as the 33-T
Plenty to choose from on ebay.
Finding accurate measurements of the gears is the biggest problem.
Happy hunting

[viktor j nilsson]

Thanks! I definitely need to read up on the gear terminology, but this looks like a fun project.

[viktor j nilsson]

In the end, I didn't need to explore the gear market after all.

Background: I had a M20 stage lying around that did not work in either direction, I got it as a part of a "for parts" stand that I had bought mostly for the achr.apl. condenser. Forward-backward motion didn't work at all, the gear didn't even engage with the gear rack. Sideways, it was clear that the plastic gear had been been wrecked, it was only spinning and giving up a plastic 'crunch'. Ouch!

However, after closer scrutiny I realized that it was only one side that was affected. The other plastic gear was in great shape. So I simply took a sharp knife and shaved away all the tooths on the broken plastic gear. When it no longer engaged with the brass gear, the controls on the other side worked smoothly. Of course, I can now only use one side to move it sideways (the right-hand side) but I think that this will work OK in practice.

And whatabout forward-backward movement? For some reason the gear rack on the underside of the top half wasn't high enough to engage with the gear. So I simply shimmed it up with aluminum foil, folded lenghtwise 15 times or so. That solved it perfectly. No idea why this was so, maybe someone had switched parts between two different stages? I know Wild are known for having fitted these types of parts by hand with extreme precision. Maybe that means that you can't just move the top part of one stage and match it with the bottom part of another stage? I don't know, but the stage works now at least.

[Grahame]

Nothing like a bit of creative engineering to get things running again

[viktor j nilsson]

Just for the record, I think that I will want to replace the aluminum shims with another material, since aluminum corrodes when in contact with brass.

[Hobbyst46]

Just for the record, I think that I will want to replace the aluminum shims with another material, since aluminum corrodes when in contact with brass.

Please note that in principle, any pair of non-identical metals will corrode when in contact with each other and in the presence of moisture. I am not sure that in this respect, aluminum is worse than carbon steel, for example. Brass shims should be best, bronze next (I guess).

[viktor j nilsson]

Just for the record, I think that I will want to replace the aluminum shims with another material, since aluminum corrodes when in contact with brass.

Please note that in principle, any pair of non-identical metals will corrode when in contact with each other and in the presence of moisture. I am not sure that in this respect, aluminum is worse than carbon steel, for example. Brass shims should be best, bronze next (I guess).

True. I was actually thinking of making shims out of thin plastic, like acetate films. Any thoughts on that? But honestly, I don't think it would be a huge problem to leave it as it is.

[Kyriacos]

Dear All

I wonder if you can help

I have a WILD M20 standard. The fine focus adjust free spins. The Bridge does not move up/down!

Any ideas how to approach ?

Many thx

Dr K