ww2 tank gun sight cleaning

[nathanieljr]

Hi all,
I was trying to clean a ww2 No 39 gun sight I have as there is some dust on the lenses inside. However, although I could get to most of it to clean, I couldnt get into the head of the sight, the tihickest portion. As the view through the sights hasnt changed at all, this seems to be where the dust is. Anyone know how to get in?
Thanks,
Nathaniel

 

[M8owner]

A hammer will work to get in, but going back out will be a challenge. :bigsmile:

I love tank sights. What type is that?

 

[reccetrooper]

So called “dust” inside optics can be the interior coating of the components deteriorating with age. I don’t think there is anything that can be done as optics are sealed when made and the “dust” is within the sealed components.
I seem to recall reading on Gunboards about someone shooting an Arisaka sniper rifle with a mint original scope, after the first shot the scope was filled with little specks of “dirt”.

 

[tankbarrell]

No 39 is for 6pdr armed tanks.

 

[Fred]

Hi Nathaniel
Its generally not a good idea to dismantle optical instruments unless you are confident that you can reassemble it correctly. I know from experience that its easy to do more harm than good. However, if you want to proceed, the optics are retained by the countersunk screws on the sides of the thick part. There is probably a single screw close to the eyepiece which if removed will allow the lens assembly to be unscrewed or withdrawn. Be careful with the screws, they are only brass and usually quite tight.The dust particles are probably on the plate glass which has the crosshairs etched onto it. Clean this carefully with a soft brush but don't use any liquid cleaners because they may wash the pigment out of the etched lines. I was able to restore a No.51 scope in this manner but after a while the dust reappeared, probably particles of the internal paint coming loose.

Good luck
Fred

 

[nathanieljr]

ok, thanks!
Ill have another look