Micrometer inspect and repair

[EOsteam]

I have a few micrometers that were inherited with my lathe purchase that do not turn smoothly. They have proved resistant to every solvent and oil that has been tried. It's now time to send them in for an IRAN (inspect and repair as necessary). What shops (preferably here in the Pacific Northwest) do folks have experience with that they can recommend?

Thanks,

HJ

[whateg0]

Have you removed the thimble to clean them? Or just soaked them?

Dave

[Harold_V]

Due to prolonged inactivity of use of my precision measuring instruments, two of my micrometers became sticky. Why the others did not, I can not say, but the oil appeared to polymerize (for lack of a better description).

I tried a number of solvents, but nothing worked. Even if they got free, the condition would repeat itself in short order.

Then I tried using some ATF for lubrication (thanks to a suggestion by Jim Rozen). Surprisingly, it worked. The solvents in that formulation appear to overcome the problem.

I'd certainly give that a try before investing what most likely would be more money than the value of the instruments in question--as almost no one works for a reasonable fee these days.

H

[pete]

Well there not in the Pacific Northwest but in Illinos. Most of the Youtube guys seem to use M.R. Tool Repair and are real happy with the work and prices. Maybe yours were "re-oiled" at some point in a misguided attempt to look after them. Using the wrong oil and / or too much seems to do more harm than good after a few years. The wrong oil dries and gets gummy in a fairly short time and too much oil just seems to drag in the dirt and dust. It's also possible your mikes might even have had a few coolant baths and that's even worse after that dries out. A single drop or less of Starrett instrument oil is all that's needed on the thread. If you've got an ultrasonic cleaner then careful disassembley and a run through that of the internal parts might do it. Even the Starrett instrument oil will dry given enough time and I've got one of there indicators that's just starting to get a bit slow in it's return travel. But it took almost 30 years to do that. Adam Booth on his YT channel has shown some before and after shots of some pretty beat up indicators repaired by M.R. Tools and they did a very nice job.

[SteveM]

ATF can do wonders, but it can't wick into the small spaces to do the work, so thin it 50/50 with acetone. I keep a bottle of that handy.

For indicator repair, there is also Long Island Indicator.

Once it's in the box, it doesn't care where the repair shop is.

Steve

[10KPete]

If your micrometers are Starrett with the rotating lock ring around the spindle then you want to take care reassembling. Unless you are very lucky you will need to make a simple tool to align the ring with the spindle hole before trying to get the spindle through. A pin a few inches long that is exactly the diameter of the spindle with a bit of taper at the end does the job. And unless that pin is hard, the sharp edge inside the lock ring will 'pick' the pin making it harder to pass. My trick for this is to gently break the inside edge of the hole in the lock to get rid of the sharp edge. Then it will not dig into the pin!

I've been doing regular service on all my stuff and mics are part of the routine... And Tool and Instrument Oil is the right stuff.

Hope this helps,'
Pete

[Downwindtracker2]

Heresy alert !! Gun oil can give problems. sticky in a trigger is much worse problem than sticky in a mike. Someone on a hunting forum mentioned using synthetic motor oil, Not the Dino Stuff, 0-??wt Mobil One. I've been using it on my rifles for 10 years without any problems. I doubt that I live long enough for a problem, I'm only 68.

[pete]

For guns and especially trigger assembleys I usualy flush them with an electrical contact cleaner whenever I seperate the stock from the action and barrel then a drop or two of gun oil. I've got a Jewel made 2 oz. trigger on one of my guns and it's real fussy about being clean and lightly oiled. Mine are all bolt actions and other types wouldn't be as easy of course. That contact cleaner is the best I've found for flushing old lube out of anything. But I've not tried it on anything that's really gummed up.

[Downwindtracker2]

Gun oil turns to glue in the cold. But syn doesn't. It stays light. There are lots of stories of firing pins that didn't move.

[EOsteam]

Here are pics of the two problem micrometers. They have both been cleaned in ATF and then sprayed with Brake Kleen and finally a drop of CorrosionX was placed on the threads. There was no difference at any point in the process of the force required to turn the thimbles. They are just as hard to turn now as they were before I started. They Mitutoyo inside micrometer turns really stiff. I really have to work to get this one to move. The Starrett turns much easier but the force is still too much to allow the Ratchet to turn the thimble.

Any help you can offer will be gratefully appreciated.

Thanks as always,

HJ

[10KPete]

That nut at the back where the spindle goes in could be way tight. It should only be tight enough to take any clearance out of the nut.

Pete

[Harold_V]

What Pete said. Also, the ATF process does not yield instant results. In fact, you could benefit by dismantling the micrometers, then immersing them in a shallow container of the oil. Give it time to dissolve the solids that may be present, solids that I discovered would not dissolve with strong solvents. Until they are removed entirely, the mics most likely will just return to being stiff (mine did). I'd recommend the ATF treatment before trying to adjust the nut. It most likely isn't too tight if the solids are removed.

So you'll have a better understanding, my BP mill has one shot lube. It got stoved up, so I replaced the meters. The pump, however, was VERY slow to fill (when the lever was pulled----the felt filter was likely mostly plugged by varnish). I started using ATF in the one shot pump, and it is now free working. Took quite some time, though, so, in my case, patience was a virtue.

By the way, nice mics! I can see why you are considering having them adjusted by an outside source. You'll feel much better about this thing if you can solve the riddle yourself, though! I know I would.

H