MicrobeHunter.com Microscopy Forum

Wondering of anyone had a solution or tip on how to make the focus rail on a Stereo feel smoother?.This is a brand new stereo and the ball bearings are in mint condition, I added a generous amount of Nyogel 795 on the rails to see if it made a difference with damping , but no luck. I can't seem to find the sweet spot when adding tension to the focus knob.The spring added helps a bit but I still think there's something else that can be done.....
.....this is more noticeable when focusing down..

Excuse my ignorance my friend but I wonder if it's possible that what you are looking at is not the problem.
Its just a thought but kindly look at this possibility. If things seem smooth and then seem to drag and then smooth up again, is the focus knob itself a little out of round and rubbing at a certain spot. That would drive a guy nuts trying to find it. It looks pretty close in the photo. Just a thought.
Greg

Ummm, worth taking a look at, will disassemble and report back. The mechanism is your standard rod with gear pinion, but I wonder if the tension washer is damaged.
Thank you for pointing it out.

It looks like you have gib adjustments.

I think you'll want gravity to hold the scope it the down position, rather than have it float a bit from gear lash and gradually drift down.

I'd be inclined to try a regular light grease (not damping grease on the ball bearings), forget the spring, and adjust the gib (assuming that's what's adjusted by all those set screws along the left side of the upright) for a smooth but not loose travel throughout the entire focus range.

Greg's point about a possibly bent focus shaft, missing spring washer, or interfering knob is another possibility.

If those are indeed set screws for gibs as PeteM suggests (they sure look like it), I think you've found your solution. They're common on machining equipment where you can have a very large and heavy cast iron table glide quite easily on a film of oil, the gibs is there to take up slack. With machinery, I tend to slowly tighten the screws where the dovetail is while moving the table until I feel resistance, then back it off just a bit.

In machining, there's a process known as scraping where the goal is to manually get the surfaces perfectly flat and parallel (frequently within a few thousandth's of an inch per foot) to gain (or regain) precision.

Ahhh. Yes it worked, still haven't gotten it to the way I'm expecting it to feel like. Pete mentioned using regular grease instead of damping, I'm going to try that as well.
Thank you all.

Ahhh. Yes it worked, still haven't gotten it to the way I'm expecting it to feel like. Pete mentioned using regular grease instead of damping, I'm going to try that as well.
Thank you all.

Imy guessing it's similar to this other rail design but the external screws ad the tension instead of manually having the set em when assembling?

Does the left stand have ball races or metal dovetail guides? The dovetail guides tend to run smoother. A very good system is the roller bearing guides in the Zeiss Standard line, fairly smooth and extremely durable and low maintenance. Compared to these roller guides ball races can be rougher as the contact surface is smaller and the balls stop in every surface imperfection. Like on a bicycle steering head bearing.
When you dismantle the stand and remove the grease you will be able to see whether the surfaces are precision ground or just sheet metal.