DYI Scope Repair

Pete Wass

Pete Wass

Well-known member
DIY Scope Repair

I bumped into a Youtube on DIY scope repair this morning. Three part series in which the fellow dismantles a scope, talks about the most common problems of why they won't hold POI, Makes a replacement spring to support the erector tube and re-assembles it.

This lad made his own tools as he needed them and explained the process pretty well. It appears sometimes simple things cause things to loosen up. Didn't look that difficult to do Even showed how to make reticles.

Interesting there aren't more people involved in repairing scopes.

Pete
 
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Every scope I've ever opened and every scope I've ever bought which someone else opened..... ended up with visible dust inside.
 
alinwa said:
Every scope I've ever opened and every scope I've ever bought which someone else opened..... ended up with visible dust inside.
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Yes sir! Ask Jackie about that. All microscopic things looked like rocks and his first fine cross hairs looked like ropes. I think he figured it out. Of course Cecil has been doing the erector tube spring and screw for many many years. Remington did this in the 1960s I believe. Both of my internal adjust Remington Custom Shop scopes have the screw and spring bearing against the erector tube.
Whatever is new is old.
 
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I keep a coil of 'fine' Leupold crosshair material in my wallet in a little baggie. When I pull it out to show people 99% of them are unable to see it (resolve it visually)
 
Would you mind posting a link?

There is also a book called "Guide to Riflescope Repair" by Dr. J.W. Seyfried that I've enjoyed. Probably not the ticket for your high-end scopes, but some good ideas to, as the author put it "buy 'em cheap, and fix 'em".

GsT
 
alinwa said:
I keep a coil of 'fine' Leupold crosshair material in my wallet in a little baggie. When I pull it out to show people 99% of them are unable to see it (resolve it visually)
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Many years ago a fellow I was working with decided to clean up the inside of his 18X 2” Unertl. Those things had the crosshairs mounted in a brass cylinder just ahead of the eye piece. The magnification on those old scopes was the eyepiece. I guess he was going to a higher power and as long as he had the eye piece off he figured he might as well clean out the inside. Before he put his handkerchief thru he looked first and everything looked clear so he continued. When he put on his new eyepiece it STILL looked clear. Took him a few years before he admitted what he had done.
 
As mentioned everything new is still old and Jackie Schmidt has done several of his own including freezing the erector tubes and now using glass etched reticles.
He has shared this several times over the years here and a search here might still take you to all of them that he has posted.
 
Purge with (dry) nitrogen

If you work on optics, you should have a plan to purge them with nitrogen. What I've used (for some other optics, I have not worked on a scope yet) looks like a small sandblaster, but made entirely of acrylic, with gasketed holes for your arms. Place parts and tools inside, fill with nitrogen, and keep enough nitrogen flowing in use to maintain "positive pressure" (all "air" movement is out of the cabinet).

That's the ideal. In the book I referenced earlier, I think he 'fills the tube' using much less nitrogen and no special enclosure. Doesn't seem as good, but apparently works.

GsT
 
Fred J said:
I've heard this too, but finding a source of Nitrogen in a small quantity is the problem.
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Nitrogen can be had at any welding supply. You can rent bottles, which shouldn't be prohibitive, but you're going to have to buy a regulator and that may push the cost beyond what you want to pay if you have no other use for it. If you have a friend that welds you might arrange to pay for a fill (likely under $20) in return for using some of it.

GsT
 
That is so easy

martin zuck said:
Many years ago a fellow I was working with decided to clean up the inside of his 18X 2” Unertl. Those things had the crosshairs mounted in a brass cylinder just ahead of the eye piece. The magnification on those old scopes was the eyepiece. I guess he was going to a higher power and as long as he had the eye piece off he figured he might as well clean out the inside. Before he put his handkerchief thru he looked first and everything looked clear so he continued. When he put on his new eyepiece it STILL looked clear. Took him a few years before he admitted what he had done.
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to do on a Unertl or Lyman STS if you don't realize what those two screws are holding, just ahead of the eyepiece.
 
nitrogen

i have a small B sized nitrogen tank and regulator that i used to cool p dog barrels.

eventually i quit using the regulator. if you crack the valve very gently you can get small amounts out.

a regulator is certainly ideal.
 
ray porter said:
i have a small B sized nitrogen tank and regulator that i used to cool p dog barrels.

eventually i quit using the regulator. if you crack the valve very gently you can get small amounts out.

a regulator is certainly ideal.
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People like you.... contributing to planetary gasification. Think of The Children!
 
That's a philosophical question, rather than a technical one.

Fred J said:
When trying to cure this problem, would it be wise to replace any O-Rings?
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In my opinion, yes. If you go to all the work of disassembling a scope, why not spend the extra $2 and replace anything else that's cheap and might deteriorate with time? Other folks might just give 'em a once over and if they look fine, re-use them. I can't say either school of thought is wrong.

BUT! know what you're replacing. The factory may have used something special (like EPDM or Buna-N o-rings) - if you replace those with generic black rubber, you're probably not helping anything.

GsT
 
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