This is a pretty simple scope to make. The scope is made with steel tubing and brass inserts. The bases can be purchased from optic planet. Here is the scope mounts that i used for my rifle
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The scope is made with brass inserts which are called (cells) the outside is made with D.O.M (Drawn over Mandrel) steel tubing. This is tubing that has no seams. the tubing can be purchased from Fastenal by the inch. Here is the page for the correct size tubing
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Make sure you get your tubing before you make any of the cells so you can measure the inside diameter and make the cells fit snugly in the scope. This will help keep the light out.
Once you get the tubing the cells can be made. there needs to be three cells for the lenses one for a light reducer and one for the cross hairs.
The three cells can be made at one time. First turn the outside diameter to fit snuggly into the tubing then drill through with a 1/2" drill and bore to to a inside diameter of .520. Then make a light grove in each cell about 3/16 from one edge. This will help later in assembly. Cut them to 3/4" in length, deburr and then set a side. Each cell should be bored and have a grove 3/16" from one end.The cross hair insert is made to fit snugly into the tubing then drilled with a 5/16" drill bit. deburr lightly as not to round over the hole. Then set it aside make one more insert and drill with a 1/8" drill bit. Deburr the part make sure that the edges are lightly deburred but not rounded. All inserts can be 3/4" long.
The lenses are purchased from anchor optics the size that is used is 14mm for a 3/4" tubing. here is the page that you need to purchase the plane style lenses that are not coated
(You need to Login or Register to view media files and links) if you want coated lenses they also have them but there is less of a selection of lenses and they will have to be center ground to 14mm. the three lenses that you need are objective, erector, and ocular (eye piece). There is a mathematical formula but i have not figured out all the math yet. The eye piece that I used in my scope had a F.L. (focal length) of 35mm or about 2" from the scope which is fine for a light caliber. but a heavier caliber i would use a higher F.L. of 42 would get your eye farther from the scope. The erector lens has a F.L. of 89 and the objective is a 334. this give about a 15 power scope. Now i have a objective of 279 that will be installed into another scope that will give a total power of about 8 power.
The cross hairs are the hardest to make. well more like the most time consuming. take the insert that was drilled with the 5/16 drill bit. you need to cut a cross on one end. this needs to be cut as accurate as possible. I used a spin indexer on the mill with a 3/8 dovetail cutter. cut the groves to a depth of about .020".
To be continued