Ok, scopes and laser dots. Second part

[yaric]

I started a thread about 3 weeks ago asking for advice with optics. Thanks for everyone input. I end up with 2 NcStar red dot sights. Even they are cheap, compared to real counterparts, I dont want them to be broken.

Here is brief list of my experience. It may be useful for you.

I had a link to sight protector, which connects to rail in front of sight. Dont like it. Firstly it feels flimsy, easy to brake, secondary it looks totally not cool.

Cool looking metal flush hiders are too dark for indoors.

Well, lets make own protection!

I bough 1.85mm sheet of Optics acrylic glass and test it. 340Fps BB point blank range went through and shattered all around. Dont use it, it will not hold well. I did not try more thick sheet, obviously Optics is too easy to shatter.


My second sheet was a Lexan 2.2mm. 2 hits made only a small dent less then 1mm diameter, barely noticeable. It looks like a small raindrop. I think I can have five of dents before I would need to replace protector. And it was hit at blank range.

So now we have a material. Draw circle you can fit into scope.

First you need to make a square using a hand saw.
Then cut corners using a pliers: make a cuts from both sides, then brake it with pliers.

You can use metal cutters. I did not have one, now I do, I think it will be easier.

EDITED: Best way IS to use metal cutters. It is fastest and easiest way to make desired shape. 12$ cutters will make a 25 minutes knife job a 5 minutes cut-and-fit exercise.

After 12 corners gone (4+8) you have a pretty round piece, all you need to do is cut and trim excess material on the side. Use sharp knife.

SAFETY WARNING. You still need your fingers later, dont you? Do not cut in direction of the fingers, you will end up in emergency. Use same technique as for wood cutting. Continue trimming till you fit into desired space.

Finish the sides with file. Now it is time to remove protective film

All took me an hour. Now I would do it in 20 min. My mistake was, I draw too wide initial circle, and end up with trimming over 2mm of extra material on sides.

My scope comes with front dust protector. It is a soft plastic tube with inner ring, preventing tube go deeper on the scope. I fit new BB protector in the front of inner ring, placed assembly back to the scope and now have authentic looking scope.

You see inserted BB protector down left.

[yaric]

Just made a second protector for other sight. Used metal cutter I purchased today, trimmed by small 0.5mm strips till it fit. Did not used knife at all. Done in 10 minutes.

Put few drops of superglue to hold it in place. Be careful, dont make a drop to lenses, or you permanently destroy scope.

It is a that easy. I can open a business now

[ThunderCactus]

I would have written this out for you if I realized someone wanted to know how to do it, sorry!
If you're interested to know how a machinist does it, here's how I cut over 2 dozen lens protectors;
For round protectors
1) go buy the adjustable rotary cutting tool specifically made for cutting holes out of thin sheets. (not a hole saw, but that works too I guess)
2) remove the twist drill from it if it has one, clamp your material securely and cut a circle out of it
3) Use a file to bring it to snap-in size and deburr the edges
4) can use glue to secure it if you're not confident with the snap fit

For odd shape protectors
1) Very accurately trace out your shape
2) Using a bandsaw, or preferably a scroll saw (hacksaw works since most of you don't have either of those), cut the rough shape leaving 1mm around the flat edges, more around the rounds.
3) using fabric softjaws in your vice, clamp the lens and proceed to file it to shape using the accurate trace you made as your guide. Proper filing is an EXTREMELY rare skill, even in industry, as anyone who knows how to use a file will tell you. So don't feel bad if your first lens doesn't look amazing lol
4) Deburr your edges with the file, peel off the protective plastic from both sides of the polycarbonate, and snap fit it to you optic. Usually need glue for odd shape protectors.

If you do need to glue a protector in, use a FLEXIBLE glue, like hot glue. DO NOT use superglue or krazy glue. Firstly, krazy glue has a stupidly low surface tension and it'll get all over the polycarbonate lens. Second, as soon as a BB hits it, it'll break loose.

And most importantly. Above ALL other things. When using a file, it ONLY cuts in ONE direction. So don't be dragging it back and forth with all your body weight on it.

[yaric]

Originally Posted by ThunderCactus

I would have written this out for you if I realized someone wanted to know how to do it, sorry!
If you're interested to know how a machinist does it, here's how I cut over 2 dozen lens protectors;
For round protectors
1) go buy the adjustable rotary cutting tool specifically made for cutting holes out of thin sheets. (not a hole saw, but that works too I guess)

If you do need to glue a protector in, use a FLEXIBLE glue, like hot glue. DO NOT use superglue or krazy glue. Firstly, krazy glue has a stupidly low surface tension and it'll get all over the polycarbonate lens. Second, as soon as a BB hits it, it'll break loose.

I thought about rotary tool. You need to buy a perfect diameter fit, or whole set ($$). Secondary, center drill must be removable. You never know till you buy and open package.

Glue choice, eh... you are correct, I will add hot glue on the side to hold it.

Should this be in FAQ or sticky? Or am I the only one?

[ThunderCactus]

I mean this thing:


But yeah, probably should be in FAQ, it does come up from time to time

[yaric]

Originally Posted by ThunderCactus

I mean this thing:

Wow, I had no idea this thing exists. Will it work with hand-held drill, especially without center piece?
It is only one I have.

[ThunderCactus]

lol absolutely not without the pilot drill
And when used without the pilot drill in a drill press, you need to clamp your work VERY securely, and I recommend grinding the cutting points to be more narrow

[sab567]

Maybe neebie question but...
Where do you find optic acrylic glass (especially the Lexan 2.2mm) ??

[yaric]

In the home depot. Dont look, ask
Sheet 8x11, price 11$

[bizkilter]

Great thread, Yaric. Thanks ")

[Short Round]

Made my cover up of 2 parts, the inner being a very thick piece of plexiglas and the outer a thin layer film like plastic (used to prevent and smudging on the inside lense). It is all secured by the original ring around the lense so nothing is going anywhere.

[chaz]

Picked up a sheet myself.

Came up with a nice way to keep the circle in snug but removable for cleaning, etc.
I am going to cut a groove in the outer edge of the circle and place an o-ring in it. This will make it a press fit into the scopes outer ring.

Pictures to come.