B&S indicator problems

SUCCESS!!!
so I figured it couldn’t hurt to put a touch of Tri-Flo on the pivot points etc…




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Better but still not great
Then I drowned it figuring it couldn’t hurt and I can clean it off if necessary

After a bunch ove manipulating it started to free up!
After more manipulation it’s pretty decent!
Not the smoothest, but maybe it’ll loosen up after sitting in Tri-Flo and use…
Hey! They both work now!


View attachment trim.685FB1E7-DBB2-490B-AE19-39E5BC2B39A7.MOV
 
I use to work in metrology. What I would run into was the user (in spite of being lectured otherwise) was drowning the instrument in WD-40. When it dries it makes moving parts stick.
My go-to method was a spray bottle with denatured alcohol. Remove the cover plate, spray, the guts, spray again. Once the offending substance was dissolved and rinsed out normal operation was restored. Tri-Flow might not gum it up; I never ran into that stuff.
Same problem with drop indicators. guys would oil them. Usually with a bottle of motor oil from Family Dollar. 30 wt. does not help. They're designed to work properly dry.
 
graham-xrf said:
IsoPropyl alcohol is generally pretty safe.
Click to expand...
A word of caution - I recently accidentally stripped all the markings off the dial of a Starret tenths indicator with isopropyl :cry:

Lesson learned. Test any liquid in a small spot before you use it on the dial.
 
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Yes, I believe the problem here was some type of fluid (that maybe started as a lubricant?) had dried and varnished everywhere leading to the sticking. I know drowning it in more lubricant isn't reccomended, I've just had pretty good luck with Tri-Flow cutting old stuff and providing fresh lubrication so I thought I'd try it.

The main reason is that the dial gearing was the main offender and I don't know how to open it up.
1st problem is the two mounting screws. Easy enough to get to once the guts are out (as you can see in the videos) but I can't get to them straight on with the jewlers screwdriver. The opposite housing wall makes the screwdriver go in at an uncomfortable angle.

brown & sharpe DTI 01.jpg

I did get one loose but was chewing the screw slot in the process. Installation is always harder than disassembly so I decided to pause.

Would someone have used a microscopic ratchet with a flat blade on it to install these? can anyone reccomend a tool idea to get in there straight on the screws?

2nd problem is getting the bezel off... it appears to be held on with a snap ring but I can't seem to get it out. Should the crystal pop out when levered with a screwdriver? I'm afraid to try that.

brown & sharpe DTI 02.jpg

If the Tri-Flow causes problems later I'll have to try to get to the dial gearing...
I'm definitely not cool with soaking the painted dail face in alcohol or solvent....
 
The ring looks similar to whats called a spiral snap ring. Lift the end with the large flat section up and out of the grooved edge, then gentely pull it out of the grove. Install in reverse order.
 
Good job at getting into the guts of the thing.

Next comment: Your first application of Tri-Flo on the pinion dispensed enough liquid to properly lube about 2 dozen DTIs. You need a proper watch oiler. Dip the tip in the fluid then touch to the pivot. I don't know the long term characteristics of Tri-flo. What lubricant do watchmakers use?

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Regarding the retaining clip: use a small screwdriver against the beveled end to move it toward the center of the bezel. Concurrently, lever the beveled end up (toward the camera) and rotate the bezel clockwise under the retaining clip. Continue until the retaining clip is removed.

Regarding the special screwdriver: You will probably have to make something to get it done. Because of the limited swing arc available, you will need at least 2 screwdrivers with the blades at 90° to each other, relative to the handle(s). Conceptual example below is defective due to modern manufacturing loss of knowledge.


Had to go to eBay vintage tools to find better conceptual examples.

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Also, You have set the pointer to be on Zero when the indicator is at rest. Although pleasing to aesthetics, it's not desirable for practical use. Take a look at pictures of other (factory new) DTI and you will see that the hand points at about 4:30 (standard clock face) at rest. This is so the stylus is preloaded against the workpiece when the hand points at Zero. What you want is for the hand to be on Zero when the indicator is at 50% of it's total travel, not at rest.

If I was trying to clean the indicator, with the bezel/crystal in place, I think I would give the pinion and inner case a spritz of aerosol Brake Parts or Carburetor Cleaner. What I mean by spritz is get it moist, Don't try to flush it. Work the pinion while it's wet and repeat as necessary. My thinking is that those cleaners seem to cut varnished oils well. By minimizing the amount of cleaner present, I'm hoping that it will wick up into the pinion bearing journals, but not up onto the face. YMMV
 
extropic said:
Next comment: Your first application of Tri-Flo on the pinion dispensed enough liquid to properly lube about 2 dozen DTIs. You need a proper watch oiler. Dip the tip in the fluid then touch to the pivot. I don't know the long term characteristics of Tri-flo. What lubricant do watchmakers use?
Click to expand...
With some research into precision instrument oil, it seemed light oil was preferred. Starrett doesn’t advertise what their ingredients are, but consensus seemed to be a light oil that Tri-Flow compared to.
(3 in 1, singer sewing machine oil etc)

And yes… that’s my special order ‘needle’ oiler.
Small precision amounts :rolleyes:
It’s by far the best of my options but it definitely dumped it on in the video.
I’m afraid of messing up the paint on the face so I didn’t want to use a solvent or alcohol until I can get the painted face off separate.

If I can get into the face gears I’ll try to clean properly and see if it works well *dry*

extropic said:
Regarding the special screwdriver: You will probably have to make something to get it done. Because of the limited swing arc available, you will need at least 2 screwdrivers with the blades at 90° to each other, relative to the handle(s).
Click to expand...

Hmm…. I have some ‘piano wire’. Heat and bend with MAPP gas, file round ends to sharp points? Heat and quench again for hardness? Thoughts?

extropic said:
Also, You have set the pointer to be on Zero when the indicator is at rest. Although pleasing to aesthetics, it's not desirable for practical use. Take a look at pictures of other (factory new) DTI and you will see that the hand points at about 4:30 (standard clock face) at rest. This is so the stylus is preloaded against the workpiece when the hand points at Zero. What you want is for the hand to be on Zero when the indicator is at 50% of it's total travel, not at rest.
Click to expand...

Ok. Not sure I’m following this. I moved the bezel to align w/ zero for demonstration.
I now realize I didn’t ’clock’ the needle on reassembly and it ended up “wherever it was!”
Are you talking about where to clock the needle for reassembly?
 
Mill Lee farm said:
Hmm…. I have some ‘piano wire’. Heat and bend with MAPP gas, file round ends to sharp points? Heat and quench again for hard? Thoughts?

Ok. Not sure I’m following this. I moved the bezel to align w/ zero for demonstration.
I now realize I didn’t ’clock’ the needle on reassembly and it ended up “wherever it was!”
Are you talking about where to clock the needle for reassembly?
Click to expand...

Your piano wire might be strong enough without heat treatment. If you can harden and temper, go for it.
Equally important is a very close fit to the screw slot.

Yes, I'm talking about where the needle (hand) should be clocked at reassembly. In the last video (24 seconds) in reply #12, when the DTI is at rest, the Zero is shown at approximately the 12 O'clock position. 12 O'clock is a good, common place to locate the Zero. Also shown in video, the hand is right on top of Zero when the DTI is at rest. That is because of the position the hand was pointing when you engaged the the pinion with the sector gear. I believe that because you hadn't removed the bezel and hand yet so the gear engagement was the only variable to determine which way the hand was pointing when the DTI was at rest.

By looking at the referenced video, when you lift the stylus you see the hand travels CW approximately 360°+180°+10° = 550° total travel. When you depress the stylus you see the hand travel CCW approximately 360°+180°+20° = 560° total travel. See the picture in the ad below.


If you remove the hand from the stem, when you reinstall it (after the innards are reassembled), have it pointing at about the 4:30 O'clock position at rest. That way you don't have to fiddle with clocking the pinion on the sector gear to set the hand orientation.
 
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