Restoring old Omega enlarger, Rusted screws

I picked up a trio of Omega enlargers (one D-2 and two D-5) from a relocating printing lab that was getting rid of it's darkroom gear. The machines were in storage for at least a decade and probably worked hard beforehand. They look structurally sound but there are plenty of rusted screws that won't budge but I need to loosen to align the enlarger. Any suggestions on working with rusted screws?
Cheers
Adam

Very careful placement of PB Blaster penetrating oil. If possible, heat the screws to help pull the oil into the threads. I wouldn't do this around the bellows or any glass, but it should work everywhere else. I've had some success using a high powered soldering gun to apply direct heat on small screws in tight areas.

My favorite penetrating lubricant for rusted fasteners is a 50/50 mix of automotive transmission fluid and acetone.
I find it more effective than the commercial products.

If you want a commercial solution (pun) that's more effective than most try Kano's Kroil.

Pb blaster and heat can work well. I would coat well, heat and then wait and repeat a few times. That can work, not always though.

Easy outs, which are an option if you've stripped the screw heads, they are something you would run counter clockwise that bites into the screw and backs it out.

If that doesn't work drill and retap the holes, not very fun with hand tools but doable.

Best of luck,
Nick

You could be dealing with galvanic corrosion if anything on the enlarger is aluminum. In that case, consider the screws welded in and there won't be a whole lot you can do about it. The only real way to fix it will be with a drill and then retapping the holes to a larger size. Probably not worth the effort unless you have experience doing it.

Trower said:

If that doesn't work drill and retap the holes, not very fun with hand tools but doable.

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Before doing that one might try to drill a smaller hole and try it with an extraction tap. (Only applicable if the screw heads no loger take a decent tool. Likely here this is not the case.)

Dear Adam,

Years ago when working on old motorcycles I found Dead Link Removed to be quite useful. Obviously, special care will be necessary.

Good luck,

Neal Wydra

Another approach not mentioned yet, is to only remove the fasteners that are absolutely essential to fixing whatever is broken and leave the rest as they are.

Neal said:

Dear Adam,

Years ago when working on old motorcycles I found Dead Link Removed to be quite useful. Obviously, special care will be necessary.

Good luck,

Neal Wydra

Click to expand...

You do realize, the screws in question are small, and the mechanism the OP wants to be able to adjust wouldn't withstand a pounding. Might as well pull out the BFH and beat it to smithereens.
fine adjustment tool

I also would first try PB Blaster. Kroil is also often recommended for rusted screws, but I haven't used it personally.

Make sure you have a good set of screwdrivers so you can find a bit that properly fits the slot. That will make a world of difference. Something like this.

PB Blaster has worked for me on rusted screws. The tip of a high-powered soldering gun atop the screw heads, as mentioned earlier, is a good idea.

bdial said:

My favorite penetrating lubricant for rusted fasteners is a 50/50 mix of automotive transmission fluid and acetone.
I find it more effective than the commercial products.

Click to expand...

I've found the exact same mixture to be very effective as well.

I was going to add something, but I think it's all covered above. PB Blaster is my favorite, followed by Liquid Wrench. That impact screw driver is a good idea too. Post some photos so we can see the progress.

I would not use an impact driver on an enlarger frame. No no no, not me... MAYBE just very light taps but a regular screwdriver can do that. Regarding acetone, some impure varieties can cause more corrosion if left on some metals for too long. Also, make darned sure none can leach its way to any plastic or rubber parts. I wouldn't use acetone unless I could see every part is might reach.

Old-N-Feeble said:

I would not use an impact driver on an enlarger frame. No no no, not me... MAYBE just very light taps but a regular screwdriver can do that. Regarding acetone, some impure varieties can cause more corrosion if left on some metals for too long. Also, make darned sure none can leach its way to any plastic or rubber parts. I wouldn't use acetone unless I could see every part is might reach.

Click to expand...

The way I use it is rather leak-proof. First, I prepare the mixture, then I apply it on the screw thread with injection syringe. Literally one drop is usually enough. The amount of fluid is so small that it can't leak anywhere, there's not enough liquid volume for it to leak.

The whole point of a fluid like this is to penetrate deeply into the corroded materials. Once into those, the fluid can migrate elsewhere, perhaps where you don't want it. Even PB Blaster isn't something you want in the wrong places but, as far as I know, it won't harm most plastics.

Much of my mispent youth, aside from my obsession with photography, was spent turning wrenches on rusty screws on cars. One of the most amazing things to me, when I eventually began making enough money to afford them, was how a small air-impact wrench could make many (not all) seemingly hopeless screws (bolts, if you will) virtually jump out of their rusty holes. Now this is unworkable on small screws as they just snap off on the first impact.

But there is now another class of impact driver that looks like a cordless drill, and they can do the same magic on smaller screws. I wouldn't use mine (an older 12 volt model) FORCEFULLY on anything much smaller than roughly an 1/8 inch nominal screw diameter, except as a last resort, but may be worth trying if one of your friends has one. The lower voltage ones have less torque, which is what you want for smaller screws.

Note that I used the word "FORCEFULLY" above to mean squeezing the trigger all the way. The impact mechanism doesn't start until there is enough resistance and you squeeze the trigger hard enough.

Most of the people I know have never used an impact driver, so a few words on them. First, there is very little back reaction on your hand, and second, if a Philips screw head is getting damaged such that a regular screwdriver wants to "cam out" (you have to press very hard to keep the screwdriver from slipping), an impact driver is barely affected by this. You need very little pressure to keep an impact driver in the screw head. The first time you use one they just seem like magic.

Hope the advice worked for you. I replaced many of the screws in my DII with brass screws from a nearby hardware store. They were pretty easy to come by since they are common sizes. The chrome knurled screws of course are unique and the only way to get more of those is to pick up a spare lamphouse which usually come with a few.

Hi Rick,

Actually, I own two Omega enlarger and am quite familiar with adjusting them. I trust that the OP has the common sense to realize how and when to use the tool.

Neal Wydra