Rusty threads...

Have questions about the equipment used for macro- or micro- photography? Post those questions in this forum.

Moderators: rjlittlefield, ChrisR, Chris S., Pau

ldflan
Posts: 71
Joined: Sat Mar 11, 2017 5:05 pm
Location: Issaquah, WA

Rusty threads...

Post by ldflan »

Have a Reichert condenser with a screw-on top lens that has just a trace of rust showing around the perimeter. I'd like to get it off to use a higher NA top lens. But it won't budge using fingers or nylon pliers. I could try the dental dam or hollowed rubber stopper tricks to get a grip on it, but I am pretty sure I am going to need to loosen the rust somehow. Any clever tricks or thoughts?

Thanks!

Leonard

ray_parkhurst
Posts: 3412
Joined: Sat Nov 20, 2010 10:40 am
Location: Santa Clara, CA, USA
Contact:

Post by ray_parkhurst »

Classic method is a few drops of penetrating oil.

GrayPlayer
Posts: 59
Joined: Sat Nov 14, 2009 5:44 pm

Post by GrayPlayer »

Penetrating oil, try tightening a smidgen then try to unscrew. Good luck.
Fred H.

clarnibass
Posts: 130
Joined: Fri Jun 10, 2016 11:33 pm

Post by clarnibass »

I'm not sure of the shape of this, but I need to loosen stuck and rusted screws and some other stuck parts all the time (part of my job).

Are your nylon pliers slippery? Some nylon is very slippery and doesn't have a good grip. Maybe use a material with more friction.

Try your hand with one of those silicone coasters which happen to be very grippy. If the shape allows it then you might be able to get more force than with pliers.

As mentioned repeatedly trying to tighten and loosen can help. Also gently rocking it instead of only twisting. Try pushing when twisting to open.

Penetrating oil (or even regular thin oil) can help, and best along with heat... if you have a way to heat it. Your part might not have access to heat it without damage?

Cycles of penetrating oil, heat and a thin degreaser (like lighter fluid) can help a lot. If you have plastic parts maybe check that whatever degreaser you use doesn't damage it (lighter fluid is relatively mild e.g. compared with acetone).

ChrisR
Site Admin
Posts: 8668
Joined: Sat Mar 14, 2009 3:58 am
Location: Near London, UK

Post by ChrisR »

If you have access to a lathe chuck you can squeeze it slightly, then release it, remove and rotate half the angle to the next jaw, squeeze again, etc. Obviously It's worth trying the lathe to grip to undo, as well. Protect from scratching with a layer or two of alumin(i)um cola can wrapped around the item. Heat the cola can "very" hot first to soften the metal, as it might be work-hardened to harder than a soft lens casting.

4 jaw chucks work well, you don't have to centre them for this purpose! Of course if you have a 6 jaw they'd be better.
A hair dryer is one way to heat gently. The expansion you'll get is minimal, but you will soften any threadlock/goo toa useful extent.
Chris R

Post Reply Previous topicNext topic