These brass tuners are off of a mid to later 19th century seven-string banjo.  It appears that they have not functioned for many years and are so corroded that they've turned black and are 'frozen' and won't budge.  So far I've soaked them in penetrating oil for a few days to no avail.  

I'm looking for ideas to free these up for re-use, since it's an original and rare banjo-guitar.




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Gradual application of heat? Pinpoint flame from propane torch. Just punting.

I always put old tuners in an small ultrasoic cleaner first of all. It cleans all the dirt from the tuner even deep within the groves and cracks. After that Tri-Flow.That said, these tuners was in the worst state I have ever seen! May need some steel wool or a steel brush.

The posts are tubes of brass with one small metal nail (cotter?) keeping the tube connected to a solid brass "tooth" with the cog riveted in the other end. It is possible to loosen that nail and dismantle the tuner for easier cleaning of the parts.

I have a lot of similar tuner leftovers from old European guitar restorations. The problem is that European tuners have many different spacings between the tuners posts. Not until around 1950 all the European makers choosed to use the American distance between tuner posts as a standard, the American standard have a bit more space between the tuner posts.

Thanks for the feedback.  I was also reading about vinegar and salt mixture.  Thoughts on that?

I would not use chemicals or polishes to get shiny like new brass tuners, would not look right on an old instrument. Just clean off the gunk and oil it up so it works as it should.

The problem is that the 'patina' has the gear frozen to the plate, so the tuner is not functional as-is.  I need to 'free' the gear and shaft so things spin.

And since the gear is riveted onto the shaft, I have to work with it as such, i.e. the corrosion as caused a sort-of fusion between the gear and plate. 

I don't care if they're shiny or not, just want them to function ;-)

Well, these tuners are really corroded! Your best bet should be putting them in some rust solvent oil a day or two. Maybe use a pliers to help the cog breaking loose. They should be made of brass, hard to see in the picture. Are they maybe made of iron?

If you see a nail in the post close to the backing plate, I would tap it out to loosen the cog and "tooth" from the post "roll" and clean the parts separately.

They're luck after soaking in penetrating oil.  thanks for the ideas..Tom 

There was a video on stewmac where Dan was reversing rust on some metal parts, might have been old tuner-can’t remember- with electric current. Simple setup, don’t remember the details. If that failed, I’d continue to soak them in penetrating oil/solver but would do it for a couple weeks before giving up.

This is out of left field, But I was given an old 1874 Singer Sewing treadle machine head that was frozen up everywhere.  It was not brass fittings. 

I found a you tube video where a restorer would lightly tap on the frozen lubricated, sewing machine oil, parts  with a small brass hammer, check for any movement, re lubricate and let it sit again.  Where needed he used a block of brass as an anvil opposite his tapping point to protect both ends of the frozen piece.    Coming back to it 8-10 times a day.  He seemed to believe that repetitive gentle shock through the parts eventually would open cracks in the corrosion, and allow more penetration, and repeating the process over a period of time could free things up.  He always stressed patience with the process. 

I spent 3 weeks loosing up all the frozen parts and screws, everything moves and all the screws are removable now. Can't get it to sew yet, but there is hope someday maybe.

Just a thought from the tinker/tailor part of me.

It looks like the posts are staked to the gears. If you’re going all out, what about drilling out the stake, drilling and tapping the posts in a lathe, and reassembling with countersink screws? I have to think the spiral gears are pitted and will give a rough turning action, but sometimes going to the wall for some hopeless hail-Mary is what keeps the whole thing fresh? 

Boy! From the corrosion It  looks like it was on a ship at sea, or some such saline environment. What does the rest of the banjo look like? I would think, as Mike says, that the gears won’t ever run smooth as pitted as they are. How much will they be used? Is that maybe a made in England banjo?

Anyway, if it is to be restored to functional, playable, but not really used a lot , then the old tuners should clean up good enough. Bet that tap tap method would get results eventually. Then, if you can straighten that bent shaft without it breaking, you’re home free. It would be good to keep all original,sounds like. 

I emailed the people that make PB Blaster and heard from Ted Smith in their Safety/Quality Control department. He said their product is safe on brass of that was 130+ years old and would help ease the break loose the bonding corrosion.  He said heat would help, but did not recommend using a flame heat source and said even a hair drier would help the process. 

Good luck, keep us posted.

Charley, Antikythera mechanism missing parts?  Maybe found their way onto a banjo.


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