Choronzon wrote:Seriously? You drilled and tapped the Y scale indicator for a lock screw rather than adjusting the Y rack to resolve play in the table when moving the slide by hand?
Yes I did. My stage was under $200 used & my alternative was to find a fixed stage, which I ultimately (sort of) did, although it was much more expensive.
Charles Krebs wrote:Not sure he is talking about "play" in the movement. My impression was that he preferred to physically move the slide around with the fingers instead of using the x/y axial controls (no stage clips in picture). In that case his preference is for a truly "fixed" stage.
What puzzles me a little is the:
"Shims on 4x & 40x to make objectives Parfocal"
How much do they vary? Generally with a new scope and objectives of this quality they should be very, very close (within 1/4 to possibly 1/2 turn of the fine focus). They are rarely "perfect".
So ultimately the shims turned out to be too thick (even the 0.001" shim). I ended up putting a few dots of thin paint on the 40x where the shim would sit, and screwed it on with light-medium force. So right now, if I focus the 40x on tissue (I look at a lot of skin, so I adjust the 40x so that the desmosomes b/w keratinocytes are sharp) then all the other objectives are in focus (for that specimen) & I no longer need to adjust focus. My objectives are pefectly parfocal, i.e. ZERO turning of the focus knob).
Ichthyophthirius wrote:
Hi,
Normally, that shouldn't be necessary. These objectives should be parfocal by factory setting if your cover glass and mountant are not too thick (they're designed for 0.17 mm).
One thing that influences parfocality is the position of the eyepiece diopters. I don't know if you've done this but this is the procedure for finding the right setting:
- wear your glasses if you're short-sighted
- take a sample and focus on it using the 40x objective
- switch to the 4x objective
- change position of the eyepiece diopters until the sample is in focus again
- go back to 40x
- use the microscope focus knobs to bring the sample back into focus
- go back to 4x
- use eyepiece diopters again
(maybe do this once more)
You should end up with the entire series of objectives being almost perfectly parfocal (half a turn of the fine focus knob difference was considered OK but modern microscopes can be even better).
Regards, Ichty
Much appreciated advice, but I really only had to adjust the 40x so that it was slightly closer to the stage.
Choronzon wrote:Because that stage has a built in X and Y tension control on the knobs. You can make them so tight as to be unmovable.
If I had known at the time, I probably would have gone that route. Thanks for the info.
So I ended up getting a white circular Leeds stage (out of production), and low & behold they send me the "Glide" stage instead of the fixed stage. When I called they said that they had no more circular fixed stages, but I could keep the glide stage if I wanted. Seeing that I could probably fix it, I decided to keep it.
The stage is actually 2 parts, the top fixed plate and the bottom part which is essentially a ring. The top plate was threaded as if it was made to receive screws, so I ended up having to tap & drill holes through the bottom ring part to make it fixed. I also had to bevel the light path hole so that I could flip the condenser.
