Frozen micrometer

[JScott]

I just purchased a new, old stock Starrett 436RL-3 micrometer on eBay. It arrived yesterday and externally it is just like new. The fly in the milk though is that the thimble doesn't turn!

This really was a shame because otherwise externally the mic is in very good condition. It was stored in the original packaging which was a plastic bag/sleeve in the factory cardboard case. Apparently it was in a humid location and the threads are rusty; very little rust on the outside. It will not turn or budge at all. I have contacted the seller and he is refunding my full purchase price. I didn't pay very much for it but I was hoping this would be a good one to add to my tooling.

Now, my question is, what can I do with it? I have not tried to force it other than trying to turn it by hand. My first idea is to soak it in a penetrating oil such as automatic transmission fluid for a few weeks to see if that will help to free it up. I'm looking for suggestions to rehabilitate this mic although I don't know if it will still have precision if I do get it turning again.

Thanks in advance for the advice and help I know is coming.

[12345678910]

I check to make sure the lock is off, but you already did that.

I've found Kroil oil to be a really good penetrant.


http://www.kanolabs.com/penLub.html

[Arbalest]

Perhaps this will work?

http://fergusonenthusiasts.com/restorati...harger.pdf

[JScott]

Thanks for the tips so far. I have some Kroil and was going to try it tonight. The spindle lock is rotating freely and seems to be just like the movement on my other Starrett mics. The ratchet is working fine although there is a little rust on the head of the screw holding it in place. I don't want to remove any paint or color in the engraving so I will save electrolysis for the last gasp.

[JScott]

As an FYI here is a picture of my "new" micrometer showing the overall external condition. I thought I had won a great auction when I first opened the package. As you can see it is clean with no visible signs of use, engraving, etc. Thanks everybody.

   

[stevec]

Possibly the little roller in the spindle lock is "frozen" with rust. The knurled device for the spindle lock only applies pressure to the roller to lock, it doesn't act in anyway to apply release pressure to the roller so it would seem like it's operating normally.
Hopefully the ATF and acetone(?) or Kroil soak will free it up and the threads aren't actually rusted!
If they are I fear you have a nice ornament.
Good luck.

[JScott]

Stevec, yes that it could be that the eccentric collar in the spindle lock is seized up. It occurred to me that it could be the spindle that is stuck and not the threads. I'll be sure and soak the spindle lock as well.

If I can't get it "moving" this is going to be a very eclectic paperweight!

[f350ca]

Hopefully the penetrating oil will work, as far as I know electrolysis is line of sight action, so I don't think it will remove internal rust. Anyone know for sure.
Good luck

[krv3000]

hi well you can remove the top dismantle the ratchet at the top undo the base of the ratchet but don't remove then with a raw hid hammer hold the top sleeve in your hand then hit the base of the ratchet this will free off the sleeve as its held on by a taper once off you will see a threaded ring on the top thread this is used to adjust the mane thread remove it will free of the center rod hope this will help

[JScott]

I started soaking the thimble and spindle with Kroil last night. This morning I gave it another shot as I was heading through the shop on the way to work. I am going to continue with the Kroil and then see if I can make any progress over the weekend.

The good news is I got a full refund from the seller which eases the sting greatly. Thanks for all the tips and I will post any progress.