Hi to all.
I've had a couple of attempts at servicing the stage of my AO 120 to stop it binding. It is usable as it is but every few days it starts to stiffen slightly at certain points in it's travel.
Are there any 'magic bullets' to solve this? The mechanism is a fairly straightforward rack and pinion, and there is no obvious wear. The trouble is I'm not sure if I'm setting it too loose or too tight. I applied a small amount of grease, should I try more? Is the type of grease critical?
Any ideas would be welcome!
Tim
Mechanical stage binding
Re: Mechanical stage binding
Did you clean off the old grease? Grease that was used when that microscope was made can harden over time. Maybe a cleaning with solvent then re-greasing it will help.
Re: Mechanical stage binding
Hi Tim,
when it first moves fine and then stiffens up there might be some old lubricant somehere that is dissolved over time and then slows dom the mechanism again. You might have to look more closely for old lubricants.
Stages often have big sliding surfaces and don't like to move easily with grease as a lubricant. It is then better to have the dampening at the shaft of the controls and have the sliding surfaces oiled, e.g. with machine bed oil.
Does your stage move freely withou lubricant?
I once had to repair a Zeiss-Winkel GFL stage that was dependent on such an overload of manufacturing precision that it was really difficult to set right after the wear and bumps of 60 years of use and storage. In your case there might be a slightly bent shaft too.
Bob
when it first moves fine and then stiffens up there might be some old lubricant somehere that is dissolved over time and then slows dom the mechanism again. You might have to look more closely for old lubricants.
Stages often have big sliding surfaces and don't like to move easily with grease as a lubricant. It is then better to have the dampening at the shaft of the controls and have the sliding surfaces oiled, e.g. with machine bed oil.
Does your stage move freely withou lubricant?
I once had to repair a Zeiss-Winkel GFL stage that was dependent on such an overload of manufacturing precision that it was really difficult to set right after the wear and bumps of 60 years of use and storage. In your case there might be a slightly bent shaft too.
Bob
Re: Mechanical stage binding
Bryan and MicroBob,
Thanks for the suggestions. I'm afraid I didn't clean the old lubricants off carefully, so it seems likely that may be the cause or at least a contributing factor. As it had been working fine I assumed a slight adjustment of the pinion would put things right, and I didn't spend as much time on it as I should have.
I'll try again, and work more carefully this time!
It's an irritating job though because it's difficult to judge how well it's working until the stage is replaced on the stand and everything readjusted.
MicroBob, I'll have a closer look at the mechanism, and try and use appropriate lubricants. I don't think there's any mechanical damage eg bending, as it was working perfectly until a few weeks ago.
I'll have another go, and post again with the result.
Cheers, Tim
Thanks for the suggestions. I'm afraid I didn't clean the old lubricants off carefully, so it seems likely that may be the cause or at least a contributing factor. As it had been working fine I assumed a slight adjustment of the pinion would put things right, and I didn't spend as much time on it as I should have.
I'll try again, and work more carefully this time!
It's an irritating job though because it's difficult to judge how well it's working until the stage is replaced on the stand and everything readjusted.
MicroBob, I'll have a closer look at the mechanism, and try and use appropriate lubricants. I don't think there's any mechanical damage eg bending, as it was working perfectly until a few weeks ago.
I'll have another go, and post again with the result.
Cheers, Tim
Re: Mechanical stage binding
Just a quick update -
Finally got around to spending some time on this, and it turned out to be a very simple thing.
The mechanism itself was fine, but the little micrometer indicator at the side of the stage must have been bumped at some time and was contacting the side of the stage at a certain point in its travel.
Removing and replacing it has cured the problem.
With hindsight I don't know why it took me so long to find this out but never mind! Now it's fine.
So maybe this will help someone as unobservant as me.
Tim
Finally got around to spending some time on this, and it turned out to be a very simple thing.
The mechanism itself was fine, but the little micrometer indicator at the side of the stage must have been bumped at some time and was contacting the side of the stage at a certain point in its travel.
Removing and replacing it has cured the problem.
With hindsight I don't know why it took me so long to find this out but never mind! Now it's fine.
So maybe this will help someone as unobservant as me.
Tim