I'm putting together my kit. Just got a BHM base. The coarse focus is very tight and the tension ring does not seem to budge, at least not with finger level twisting. Is it time to get out a tool to budge the ring, live with the tightness or what?
How hard would it be to disassemble and clean the knobs and related parts?
Thanks for your help!
Olympus BHM tight focus tension adjusment ring
Moderators: Chris S., Pau, Beatsy, rjlittlefield, ChrisR
On my BHM base I used a hair drier blower to blast the tension ring, in fact the entire knob complex, on the right side with hot air. It worked to allow me to loosen the tension ring such that it could be rotated with finger pressure.
NU.
student of entomology
Quote – Holmes on ‘Entomology’
” I suppose you are an entomologist ? “
” Not quite so ambitious as that, sir. I should like to put my eyes on the individual entitled to that name.
No man can be truly called an entomologist,
sir; the subject is too vast for any single human intelligence to grasp.”
Oliver Wendell Holmes, Sr
The Poet at the Breakfast Table.
Nikon camera, lenses and objectives
Olympus microscope and objectives
student of entomology
Quote – Holmes on ‘Entomology’
” I suppose you are an entomologist ? “
” Not quite so ambitious as that, sir. I should like to put my eyes on the individual entitled to that name.
No man can be truly called an entomologist,
sir; the subject is too vast for any single human intelligence to grasp.”
Oliver Wendell Holmes, Sr
The Poet at the Breakfast Table.
Nikon camera, lenses and objectives
Olympus microscope and objectives
http://www.garrettwade.com/product.asp? ... MgodeEIAog
http://www.edmundoptics.com/lab-product ... liers/2931
http://www.dmctools.com/store/catalog.a ... _ID%3D4952
I like these
http://www.ewdsolutions.com/default.asp ... cialty.htm
http://www.pilotaircraft.com/product_in ... ts_id=9817
I also have a couple of these which I got surplus and they were pretty worn out and the slip joints aren't so good. They might be better starting from new.
If you buy some of these buy spare jaws if they are available. You will be glad you did. I have found them very useful on a variety of optical and other jobs.
http://www.edmundoptics.com/lab-product ... liers/2931
http://www.dmctools.com/store/catalog.a ... _ID%3D4952
I like these
http://www.ewdsolutions.com/default.asp ... cialty.htm
http://www.pilotaircraft.com/product_in ... ts_id=9817
I also have a couple of these which I got surplus and they were pretty worn out and the slip joints aren't so good. They might be better starting from new.
If you buy some of these buy spare jaws if they are available. You will be glad you did. I have found them very useful on a variety of optical and other jobs.
-
Charles Krebs
- Posts: 5865
- Joined: Tue Aug 01, 2006 8:02 pm
- Location: Issaquah, WA USA
- Contact:
I second the "hair drier" heat approach.
If you look at the tensioning ring you will see that there are several holes in the ring. These can be used to adjust that ring. It is suggested that a screwdriver (or any small metal bar) can be inserted into the holes to provide leverage to turn it... that is actually what they are there for. As you look axially "into" the focus knobs, a counterclockwise rotation of the tensioning ring should loosen the coarse focus movement.
One caution...
It may well be that moving that tensioning ring solves the tightness problem. But it could also be caused by a thickening in the grease used in the focus gear-train. If that is the case, be cautious with the amount force used to move the focus, or you could potentially damage internal gears. Some heat could help in this regard as well.
If you look at the tensioning ring you will see that there are several holes in the ring. These can be used to adjust that ring. It is suggested that a screwdriver (or any small metal bar) can be inserted into the holes to provide leverage to turn it... that is actually what they are there for. As you look axially "into" the focus knobs, a counterclockwise rotation of the tensioning ring should loosen the coarse focus movement.
One caution...
It may well be that moving that tensioning ring solves the tightness problem. But it could also be caused by a thickening in the grease used in the focus gear-train. If that is the case, be cautious with the amount force used to move the focus, or you could potentially damage internal gears. Some heat could help in this regard as well.
As Charles indicated, when I said "finger pressure" I meant finger pressure applied to a hex wrench that fitted into any one of the holes in the tension ring.
NU.
student of entomology
Quote – Holmes on ‘Entomology’
” I suppose you are an entomologist ? “
” Not quite so ambitious as that, sir. I should like to put my eyes on the individual entitled to that name.
No man can be truly called an entomologist,
sir; the subject is too vast for any single human intelligence to grasp.”
Oliver Wendell Holmes, Sr
The Poet at the Breakfast Table.
Nikon camera, lenses and objectives
Olympus microscope and objectives
student of entomology
Quote – Holmes on ‘Entomology’
” I suppose you are an entomologist ? “
” Not quite so ambitious as that, sir. I should like to put my eyes on the individual entitled to that name.
No man can be truly called an entomologist,
sir; the subject is too vast for any single human intelligence to grasp.”
Oliver Wendell Holmes, Sr
The Poet at the Breakfast Table.
Nikon camera, lenses and objectives
Olympus microscope and objectives
I lost my brain somewhere. My BHM is knurled. I saw Charles' post and took a quick look at my base. BUT I have 2 bases adjacent on the bench, one a BH2-BHS that has the holes and the other a BHM lacking holes. I just checked the BHM and can easily rotate, stiff but moveable, the tension wheel with finger pressure.
NU.
student of entomology
Quote – Holmes on ‘Entomology’
” I suppose you are an entomologist ? “
” Not quite so ambitious as that, sir. I should like to put my eyes on the individual entitled to that name.
No man can be truly called an entomologist,
sir; the subject is too vast for any single human intelligence to grasp.”
Oliver Wendell Holmes, Sr
The Poet at the Breakfast Table.
Nikon camera, lenses and objectives
Olympus microscope and objectives
student of entomology
Quote – Holmes on ‘Entomology’
” I suppose you are an entomologist ? “
” Not quite so ambitious as that, sir. I should like to put my eyes on the individual entitled to that name.
No man can be truly called an entomologist,
sir; the subject is too vast for any single human intelligence to grasp.”
Oliver Wendell Holmes, Sr
The Poet at the Breakfast Table.
Nikon camera, lenses and objectives
Olympus microscope and objectives
-
Charles Krebs
- Posts: 5865
- Joined: Tue Aug 01, 2006 8:02 pm
- Location: Issaquah, WA USA
- Contact:
Well, you have the actual piece if there is no slot or hole then that's the way it is. 
From two "generations" of BHMJ instruction manuals:
But yours is not the "J", it is the full stand from the older BH series. In that manual:
BTW... the manual for that stand is here:
http://www.alanwood.net/downloads/olymp ... ctions.pdf
From two "generations" of BHMJ instruction manuals:
But yours is not the "J", it is the full stand from the older BH series. In that manual:
BTW... the manual for that stand is here:
http://www.alanwood.net/downloads/olymp ... ctions.pdf
-
Charles Krebs
- Posts: 5865
- Joined: Tue Aug 01, 2006 8:02 pm
- Location: Issaquah, WA USA
- Contact:
To my surprise, hair dryer heat did its magic.
Hey, why the surprise?...NU and I weren't just flapin' our gums here! 
If that tensioning control stiffens again you should be able to get a drop of machine oil onto the threads. Ideally old scopes should have old grease removed and be re-lubed, but often a drop of oil on a the threads of a ring like that will keep things going smoothly for a long time.
This post was helpful, I've bought a BHM stand and had similar tension ring issues. I also have another problem with the fine focus knob, it has about one full turn of slack in it before it engages the stage. Has anyone experience in eliminating this backlash?
Linden Gledhill http://www.flickr.com/photos/13084997@N03/
I did some more testing and it appears that the fine focus works ok when I turn the knob slowly. It only appears to slip when I attempt to focus more rapidly. As anyone come across this before? could it be due the grease drying out?
Linden Gledhill http://www.flickr.com/photos/13084997@N03/