What's the best way to clean this up?

[dbb-the-bruce]

I acquired this as part of one of the collections of random machinist tools I have. It may actually have come from my father in-laws set.

Everything functions smoothly, it has a nice feel to it. However the surface rust has made it pretty much useless. I had set it aside with the idea of some day bringing it back to usable condition. I like old tools and would actually use this if I could read it.

What's the best approach to clean it up?
Any advice on how to bring it back to life?

-Dave

 

[MontanaLon]

That isn't bad at all. First step would be a bath in evaporust then a light scrub with scotchbrite. Oil and put it back to work.

 

[dbb-the-bruce]

I'll buy some tomorrow. How far apart should I take? Soak it as is then, take apart and oil?

 

[MontanaLon]

I'll buy some tomorrow. How far apart should I take? Soak it as is then, take apart and oil?

You will probably want to at least take it apart to where you can dry it out after the soaking. Take the thimble off at minimum. After soaking rinse with clear water and dry then soak with WD-40 to get rid of the water, then wipe it off and put a light oil for corrosion protection.

 

[mikey]

I agree that you should disassemble it and try restoring it but first check the contact faces on the anvil/spindle. If there is any rust or pitting there then it isn't worth restoring unless you are capable of precision lapping. You have some significant pitting and while Evaporust is pretty good, I find electrolytic rust removal better for blasting ruts out of deep pits so consider that as an option. Regardless of your method, I suggest you tear it down completely if you plan to restore it.

 

[middle.road]

Be real careful with the evap-o-rust. I've had a couple of un-desirable results when left in for too long.
dis-assemble it all the way.
On the 'C'-frame I would try some fine polishing compound first before Evap-o-Rust in order to preserve the etchings.
Mother's aluminum and mag wheel polish or similar. I've used a 2" buffing wheel at low speed along 1000 grit wet-or-dry for the stubborn spots.
Thimble looks like it could stand a hour or two in Evap-o-rust.

Saw one of the YouTube creators using WD-40 Rust Remover Soak with good results.
I'm going to give that a try when my jug of Evap-o-Rust is used up.

 

[dbb-the-bruce]

An update.
I got a jug of Evap-o-rust today and I also did some googling about how to dismantle it.


Easy enough to remove the shaft just by unscrewing it. Based on my YouTube research, I started looking for how to adjust the zero. The video showed scale / tube attached to the C part as being adjustable using the wrench. So I looked for the hole for the wrench to engage in and there isn't one. So I took a close look at the other half and -BINGO- there it is.


And behold, there is the reason this mike was "scrapped" - If you look close you can see the pin from the wrench has broken off and is stuck in the shell. Making it very difficult or impossible to adjust zero.

So based on my understanding from the video, the shell should be a very tight slip fit on the shaft.
So I grabbed the shaft in a vise between two blocks of wood with a strip of inner tube rubber to hold on to it. With a little WD40 I was able to get the shell to turn on the shaft - still very stiff, but at least adjustable, sort of.

Try as I might however, I couldn't get the outer shell to slide off the shaft. It looks like the ratchet mechanism is a sold part of the shell, meaning it would have to slide off the backend.

Am I correct? is there something else preventing me from removing the shell from the shaft?
I'm thinking that if I can remove it, I'll be able to remove the broken pin.

I can deal with this the way it is but would like to get it right if I can - before I soak it in the evap-o-rust.

 

[Canyonman44]

Hi Bruce, I kind of agree with Mikey, electrolytic removal is the first way to go. I think you'd be surprised. It also gets in there where you can't disassemble. I have also used an ultrasonic cleaner. Plus when it comes out you can still go the Evaporust way if needed. I have done many mikes this way.

Ken

 

[dbb-the-bruce]

Done with it and not a bad result.


This was a fun adventure.
The one thing that tripped me up was I used WD-40 to loosen the cap that hold the thimble in place. When every thing went into the evap-o-rust, the small quantity of WD-40 left turned to cheese. Either that or there was something on the green scotch-brite clone that turned gummy.

Regardless of the source, the leftover crud made the micrometer action sticky.

So I spent about an hour or more getting high on Xylene, running it back and forth until it ran smooth.
I used India ink to highlight the engraved marks.

I'm pretty happy with the results and learned a lot about micrometers. The 0.010 thimble mark is still pitted and hard to read, but the rest jump out. So I just have to remember - if I can't read the number on the thimble, it's 10.

Checked it against some standard blocks and shim stock and compared the results to my digital Starrett and they both agree to within a 0.0005

Good enough for me.