Sticky Starrett Micrometer

I picked up a used Starrett micrometer (436) that appears to have a lock ring that is sticking slightly shut. The lock ring is mounted in a slot on the micrometer frame near the barrel end. When I back the outer knurled ring off to release the lock, the outer ring spins freely, but the inner split-ring that grabs the spindle does not appear to be releasing completely. I took the spindle out and visually confirmed that the split ring is hanging in the spindle bore very slightly. Light machine oil did not help the situation much. This brings me to three questions:
1) How do I remedy this situation?
2) How do I get the lock ring assembly apart so I can clean it?
3) What kind of cleaner do you use to clean the barrel and knurled cap/ratchet? (there is a small amount of black grease embedded on the barrel/ratchet)

Thanks for any advice you can send my way on this one.

Hello,

Just did a double check on my 0-1 436 to be sure.
The knurled lock ring assembly pulls straight out from the frame. Look for the tiny keyway in the frame towards the anvil side. You may need to use some light oil to help free it up. The ring pulls out in the direction of the keyway. Do this over a table with a rag so you won't lose any parts.
I personally use lacquer thinner and re-oil with a good light instrument oil. I like TRI-FLOW oil.
Good for cleaning,also. Carefully reassemble to get inline with the spindle. A couple of lock-unlocks usually does the trick.
In the sixties my mentors usually removed the locks altogether so they would not drag or cause problems.I've always left mine in and just made sure they were taken care of as with the rest of the mike.

Brian

FWIW, I've always had pretty good luck cleaning my micrometers with WD40. Spray it inside the nut, inside the barrel, and down into the hole in the frame til it runs off, work the mechanism, wind the screw all the way in or out, and then, taking due care of eye and respiratory safety, take it apart again and blow all the WD40 out of it. Then, lubricate again with a light instrument oil...I use air tool lubricant.

georgeL --

Those lock rings will stick like you describe if they are turned to the locked position while the spindle is out. If that's what's wrong with your mike (likely, but there may be something else going on), you'll need to remove the spindle and slide the lock ring assembly out of the frame.

There is a slot -- or there are slots, I forget which -- extending through the length of the ring that you'll need to open slightly. (An X-Acto blade makes a dandy wedge to open the slots.) Once you've done that, put the lockring back into the frame and follow it with the spindle.

John

I have a cheap micrometer with the same problem

looks like on mine the locking mechanism damages the spindle (planned obsolescence) after I tighten it a few times

since Starret is now built over there ...........


this problem would not occur on a regular mike

when I buy stuff, I always look for the part that is made to break/cause damage and fix it

in a photo flash they use cheap insulation on wire

on an otherwise perfect quality magnetic indicator holder they make one part from cheap plastic that will break after its second use

and so on

just don't use the locking mechanism, tighten it to snug and leave it that way

Glad for the fix replys as I have an old Starrett that is doing the same thing.
Michael

AeroKroil......like it says on the can..."Kroil it, Don't spoil it!

Really Kroil has some solvent characteristics to it way more so than WD-40 and tends not to dry with a sticky residue. It is mild enough on paints. Thin and creepy. After flushing with Kroil it can be followed up with the instrument oil.

Thank for all the help!
Once I got the lock ring out I found that the little (~0.020) pin for the cam had disintegrated (I took another micrometer apart to see how it was supposed to look). I removed the pieces and now the mic spins free albeit the locking mechanism doesn’t work, but that doesn’t bother me much and eventually I'll make another pin for it.
Thanks for your help!

george

Hey, I’m new here. This thread helped me!

Wanted to contribute with some pictures for the next person who’s scratching their head how to loosen the lock after fumbling with it with no spindle installed.