Suggestions on how to free up an old Brass Lens threads?

[Soomuu]

Hey everyone. I wondering if anyone has any suggestions on freeing up some threads from a brass lens?
I'm trying to free up the front and rear elements so I can clean the inside of the glass but can not seem to unscrew them. I'm guessing they are seized from corrosion. The lens was seized to the flange but I managed to get that loose.
If anyone have any effective solutions, i'd appreciate it.

Thanks,
Gary

[Jim C.]

It would help to know which lens.
I've used PB Blaster applied with a xacto knife to the gap to loosen the threads
there are other brands of penetrating oil, Liquid Wrench is another,
it may take a few applications and a few days. Some heat from a blow dryer helps
in between applications of a penetrating oil too

[MrFujicaman]

KroilOil.

If that doesn't work, It's crossthreaded !

www.kanolabs.com

[gphoto]

PB BLaster works very well

[onnect17]

104087

You should be able to find it in auto parts stores.

Use rubber gloves to improve contact and rotate the lens to change the force vector (similar when dealing with lens filters). Do not use any other tool, like a oil filter remover or similar.

The most important part. You should cover and tape the glass for this type of work because some brass particles could harm the glass.

[Jim Graves]

Also .... get one of the wrenches with a rubber loop ... they are called strap wrenches ... similar to an oil filter wrench. It will make a HUGE difference in the torque you can apply and wll not damage the soft brass. And, if its really stuck, buy one of the two wrench seta so you can twist both ways.

For example: LINK (http://www.amazon.com/s?ie=UTF8&page=1&rh=n%3A228013%2Ck%3Astrap%20wrenches)

[Soomuu]

Thanks for the suggestions guys. I actually tried some lubricant called "The Original Release all" that mechanics supposedly use for seized threads.
No luck though.
Jim, I may try and find those rubber wrenches that you suggested. They look a lot safer than the metal oil filter ones.

[onnect17]

Gary,
Another option is sending the lens to Jim or to me. Worst case scenario I'm less than an hour from SK Grimes and I can ask them for input.

Remember, not all brass materials are the same, some are quite soft. Again, IMHO, you can do it without tools.

[DrTang]

what about sticking the barrel under the hot water faucet?

works on pickle jar lids

[E. von Hoegh]

Hey everyone. I wondering if anyone has any suggestions on freeing up some threads from a brass lens?
I'm trying to free up the front and rear elements so I can clean the inside of the glass but can not seem to unscrew them. I'm guessing they are seized from corrosion. The lens was seized to the flange but I managed to get that loose.
If anyone have any effective solutions, i'd appreciate it.

Thanks,
Gary

Kroil as a first choice, PB Blaster is a good second choice. Warm the lens, apply the penetrant - as it cools, it will draw the penetrant in. Be patient! These things can take days, weeks to loosen. Above all, do not force anything. A strap wrench will still apply some asymmetrical force, so stick to the rubber pad for grip. You cam place the pad on a flat surface and press the lens down on it, you can apply a lot of tourque this way.

[goamules]

People have already addressed the two things needed, lubricant and torque. Lubricating or dissolving old lubricant being given most comments. I'll say that sometimes it takes an extreme grip to get a stubborn element started. All the solvent (I like using Naptha/lighter fluid) in the world won't help one that was simply screwed down too tightly. For that, you need to be able to grip the element, and the barrel, very well. This is difficult with lenses larger than 2 inches in diameter.

What I have done is make a custom, fitted wrench or vice. To do that, take 1x4" boards, about 3 feet long. Place them side by side, and set the lens straddling the crack between them, on one end. Use the lens to draw a circle onto the boards, around it's circumference. Use a coping or jigsaw to cut out the half circle on each board. Line it with rubber inner tube. Cut a small notch in the opposite side of each board (yellow arrow) and then loosely wrap bailing wire around the end end with the cutout so it creates a "nutcracker". Here is a picture of one side, I don't have the other anymore. Basically you get someone to hold the lens barrel, then grip the element firmly and twist with the wrench. Has worked for me many times. You don't need a lot of pressure, and you want the cutouts lined with soft rubber, and a firm fit, before you even squeeze the tool.

http://farm8.staticflickr.com/7314/10695196566_497efc455d_z.jpg

[Winger]

Instead of starting a new thread for essentially the same question, I'll ask here: I just got a lens on a Super Graphic (I think) lens board and I need to remove it. I can get the back cell off, but the flange is tightly attached to the front cell and there's also a raised guard making my spanner wrench pretty close to useless. Will the PB Blaster and/or Liquid Wrench be my best bets to try first?

[goamules]

Um...yeah, but with the caveat that coated lenses have to be treated more carefully, you don't want strange solvents sitting on the glass. Use sparingly.

[Soomuu]

Hey guys, I'm trying again with lube and a hair dryer. Going to let it sit for a bit with the lube in hopes that it goes into the seam.

Garrett, that's a great idea with your "nutcracker" contraption! I'll have to make one like it, as it looks promising.
You sure are in season with your creative ideas! Wet Plate Pumpkin camera and Nutcracker Vices. Thanks!

[Jac@stafford.net]

I second E. von Hoegh's procedure. It is what I use to disassemble things that that are very stuck.

All I can add is to repeat the application of Kroil several times over the day(s) and gently tap the
part with a small dead-blow hammer (http://en.wikipedia.org/wiki/Dead_blow_hammer) from time to time to kick a bit of Kroil into places resisting its
absorption. If Kroil can't do it, well... I have never seen it fail.

A follow-up topic could be how to defeat bad fine threads when reassembling.
It involves using a very small surface mill at the bad spot of thread.

[E. von Hoegh]

I second E. von Hoegh's procedure. It is what I use to disassemble things that that are very stuck.

All I can add is to repeat the application of Kroil several times over the day(s) and gently tap the
part with a small dead-blow hammer (http://en.wikipedia.org/wiki/Dead_blow_hammer) from time to time to kick a bit of Kroil into places resisting its
absorption. If Kroil can't do it, well... I have never seen it fail.

A follow-up topic could be how to defeat bad fine threads when reassembling.
It involves using a very small surface mill at the bad spot of thread.

I chase the bad threads by hand with a lozenge shaped graver.

To iterate, patience is the most valuable tool you have on projects like this - use it lavishly. Thermal cycling (hardryer) and vibration (light tapping) are the second most valuable tools.

[Jac@stafford.net]

[/B]

I chase the bad threads by hand with a lozenge shaped graver.

More power to you. I respect such well-earned expertise. When I must perform precision hand-work I have to double my anti-tremor meds which work but shorten the rest of the day.

[E. von Hoegh]

More power to you. I respect such well-earned expertise. When I must perform precision hand-work I have to double my anti-tremor meds which work but shorten the rest of the day.

I limit myself to two cups of coffee, none after about 9 am. Makes a difference!

Actually it's easier than it may sound, I've been using gravers to turn parts on a watchmaker's lathe for about 30 years.

[Jac@stafford.net]

I limit myself to two cups of coffee, none after about 9 am. Makes a difference!

Actually it's easier than it may sound, I've been using gravers to turn parts on a watchmaker's lathe for about 30 years.

With respect, you probably do not have Familiar or Essential Tremor, and i am happy you do not.

[John Kasaian]

Penetrating oil like WD-40 or Liquid Wrench, apply lots of heat with a blow dryer and use those strap wrenches?

[DKirk]

Just a thought, but are there any grub screws hidden in the threads?

[gleaf]

Some warming go. We allow 2 minutes per degree C for optical instruments to adjust to a new environmental temperature. Penetrating oil of choice. Heating cooling cycles. And time.
For heating perhaps an old fashion incandescent bulb in a cardboard box. Watts to get your max temperature well below 451 F. Where paper ignights. And a cycle timer. 3 hours on the off for a few days or mute should work the dimensions enough micro strokes to lubricate the thread bind.

[E. von Hoegh]

Penetrating oil like WD-40 or Liquid Wrench, apply lots of heat with a blow dryer and use those strap wrenches?

WD-40 is a poor penetrant, furnace oil works better than WD-40. Strapwrenches apply force asymmetrically; there is a pinch point where the strap leaves the object. This means that they are very good to turn a rigid object that must not be marred, but not so good to turn something like a thin brass lens barrel - they may actually make it grip the cell tighter.
As I pointed out, your most useful tool here is patience - use it lavishly.