I made one more stab at making a decent looking rear sight for my Christian's Spring rifle today, and documented my progress. I pretty much made it up as I went along, with some lessons learned from previous failed attempts, so this is just how I did it today. Comments and critiques are welcome.
RCA doesn't have a good picture of the sight on the gun I am making, but I have a picture of a copy made by Jack Brooks. It's not my photograph, so I won't post it here. You'll see at the end, and you can also reference Curtis' Christian's Spring build along to see his version if you wish.
I started with a block of steel cut from some scrap found in my yard. It is quite hard steel, so this time I attempted to anneal the block after I cut it from the bar steel. I think it helped, but I suspect I did not get it hot enough for long enough to really soften it.
Here is cutting out the block from the rusty bar stock:
This bar stock is just wide enough to match the maximum width of the sight after light filing. I cut the block to be a fair bit longer than required to give me room for error, because my last one ended up short due to some errors on my part.
Next, I floated the bottom of the sight block on a file to provide a level surface from which to true all the other sides:
On the bottom photo above, you can see that the left side is not leveled out, but I know that it will get cut off, or at worst I will only need to true up a small bit. The bit at the far right corner that is not true is very close and will be either filed off, or will not be part of the dovetail because it will overhang to the side.
Next was to true up the sides. The back edge was most important, because only a small portion of the sides will remain after shaping. Here's a pic of starting to true up the back edge:
After that, I wanted to clean up the top face of the sight block. It doesn't need to be terribly square because only a very small portion will still exist at the end. I use a pair of calipers to scribe a line at the right height on each edge, as a guide to filing. Shown here:
You can just see the scribe line if you look close.
Once everything was trued up relatively close, I drilled for the light gathering aperture on the sight. I found that it was easiest to use this as the centerpiece around which to shape everything else, especially if it ends up not where I wanted it....
I used the calipers again to find the centerline, and also to mark the distance forward from the rear of the sight. I then center punched and set it up in my drill press vise.
I drilled down just past the point where the nose of the drill had fully sunk, leaving just a slight straight wall on the edges. As predicted, my drill bit wandered a tiny bit, or I didn't line it up well. It ended up maybe a millimeter off to the side. There is just enough width to the block that I can make up for the drilling error. You can see the lighter scribed line that was my original center line, and then the darker line that I scribed noting the new center. That showed me how far it was off, and I figured I could deal with that.
Next was to tackle the back portion of the sight. There are two step-downs, one is for a decorative back "bench" and the other is for the dovetail. It will become clear in a moment. I scribed a line across the top of the sight, just behind the aperture hole, and then two more scribe lines on the side for the two step downs, or step "outs". You might not see the scribed lines well on the photo. Sorry.
I used a jeweler's saw on the top of the sight blank to strike a line for cutting or filing. Depending on your skill, you could use a hacksaw here or use a file with a safe edge. I think I went the file route when I did this one. here is the back edge with the step out, and another bit left over for the dovetail:
Now on to the front portion of the sight. I apologize, I didn't take as many pictures from this point on, still getting over a virus and getting tired/lazy.
Anyway, first is to cut down into the sight aperture just to the base of the hole I drilled. That establishes the front of the sight leaf. I did this with a hacksaw, and someone more careful or accurate would have made a cut that was more perpendicular to the length of the sight than I did... more file work for later!
I don't have a picture of that cut. Next, this sight has a square ridge just in front of the sight leaf, so I cut down to establish that height. Will become apparent shortly.
Finally, I wanted a lower and somewhat level surface for the remainder of the front of the sight. I scribed a line along the edge of the sight to establish the height of the front portion. I then cut down with a hacksaw like you would when you cut a dovetail.
Here is a pic of all those cuts. You may notice that some at the back end are not as deep. That is in order to establish the front of the leaf and that square ridge in the front. And yes, I know the cuts are not parallel and nice looking!
I cut off the sprues with a hack saw, being careful not to cut into the square ridge. After cutting and filing, here is the result in rough form:
Next is to trim the width of the front, all the way back to the leaf:
The front portion of the sight is beveled side to side. So, I scribed a centerline on the top, and then scribed a baseline on the side to match the depth of my intended dovetail. I then hacksawed away, again like on a dovetail being careful not to exceed the scribed lines (most of the time...).
I hacksawed both sides and then filed down to the scribe lines. Here is a picture after filing both sides.
Towards the end, you have to play the angle of the file to see that you meet the scribed line on the side and the top centerline simultaneously.
At this point, the front is still long and will be shortened.
I then used a round needle file and a chainsaw sharpening file to file in the rounded depressions across the top of the front of the sight. Once I had the front depression filed down to meet the side, I cut the sight to length inside of the rounded portion, and then eyeballed a 60 degree dovetail end for the sight.
Here it is roughed out:
I think my process worked, although I could have been more accurate with many of my cuts. This was attempt number 5 to make this sight. Attempt number 4 turned out looking stubby, and I just couldn't live with it.
In the end, this one still looks a bit stubby and it didn't occur to me why until the very end. It's all too high. I didn't have a good way to measure the height of the example I had to look at, so I used the sight off my Chamber's Isaac Haines. I think it's just too high for this kind of sight, and lowering everything will help it to look right. Fortunately, I think I can file this one down to make the proportions a bit better.
I pretty much made this up as I went along, so this is not necessarily the right way to do it! Hope this helps someone out,
Cheers,
Norm
