Freeing up jammed positive lock-up bar

SP-15 Corroded Lockup Bar

I have a badly corroded lock-up bar that I would like to free up. I see numerous good suggestions on how to remove rust, but considering the steel AND aluminum construction of this bar, any suggestions on a type of penetrating oil or rust remover that would work on the movable steel components while not harming the aluminum body? I attach a photo of ‘the bar’ for reference. Any input is appreciated.
Regards, Yvon

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kyle van horn
14 years ago

Incidentally, I mixed some up this AM – – it doesn’t really mix – at least not the ATF that I bought (imagine the most toxic salad dressing ever). I still suspect it will work admirably, but remember to shake it before application!

Paul Moxon, Moderator
14 years ago

Absolutely, Kyle. Not just here, but in all the letterpress forums Eric, along with Fritz and Gerald offer the soundest advice and perspective available. Our craft and community moves forward because of them. Thank you gentleman.

kyle van horn
14 years ago

Once again Eric, you are the source of some incredibly useful information…

I’m going to mix some of this up and keep it on reserve in the shop.


Eric Holub
14 years ago

It might be less simple if the internal parts are also affected by corrosion or other crud. Loosen the allen setscrew near the end-piece and remove them. There are one or two rods between the end-piece and the eccentric in the center. If the rods don’t fall out easily, you may need penetrating oil. Some interesting info from a non-printing list:
<< Machinist's Workshop magazine actually tested penetrants for break out torque on rusted nuts. [. . .] They arranged a subjective test of all the popular penetrants with the control being the torque required to remove the nut from a "scientifically rusted" environment. Penetrating oil ..... Average load None ............ ......... . 516 pounds WD-40 ............ ........ 238 pounds PB Blaster ............ .. 214 pounds Liquid Wrench ........ 127 pounds Kano Kroil ............ ... 106 pounds ATF-Acetone mix.......53 pounds The ATF-Acetone mix was a "home brew" mix of 50 - 50 automatic transmission fluid and acetone. Note the "home brew" was better than any commercial product in this one particular test. Our local machinist group mixed up a batch and we all now use it with equally good results. -------------------------- So, let the oil work a while, and if the rod(s) don't fall out, work the eccentric back and forth, pushng the rods inward with a screwdriver until they can slide out. Another thing: after the lockup bar is cleaned and reassembled, if it doesn't tighten enough against the bed bearers, insert a small washer or spacer disk between the rod and the end-piece. It will push the end-piece out as much as its thickness.

Fritz Klinke
14 years ago

I’d take a more direct approach that we’ve done a number of times with these. Take the bar apart and using a wire wheel on a bench grinder, buff all the metal parts, including the spring and other parts inside the bar, down to the bare metal. Very simple.


kyle van horn
14 years ago

The good news is that this is a really simple machine, and you can’t overclean it so much that it won’t work. I suspect you’ll have a shiny lockup bar in no time.

Start with anything that says Penetrating on the label. Even WD40 will help.

I’ve also had good luck removing rust with plain old Vinegar. Soak it completely under the surface or you may risk encouraging more rust.

If it’s really stubborn and/or the screws won’t budge, consider a heavy-duty rust remover like naval jelly or the like. And then no matter how you get to the end result, you should do a full dismantle and clean/scrub.

But, unless I’m really wrong, I don’t think you have any metal vs. metal issues to worry about when cleaning this thing, especially if you end up dealing strictly with oil-based products. Aluminum and steel will both play friendly with it.

Good luck!

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