Update number 2.....heh
It has been driving me crazy not having this front sight pinned in place. It is set perfect and i don't want it to move at all. So I decided to use the existing holes in the barrel from the orginal sight. I checked it out with my height gage. I knew the pins would be close to the screw head on the counterbored side but it would definitely miss it.
Here is a picture of my barrel when I orginaly removed the factory sight. You can see the 2 pin holes in the barrel:
First I had to make a holding block. To hold the upper assmbely. So I made it out of a block of nylon. Here's my crapy sketch:
Then I had to map out the holes. Since I could not remove the sight to just check the location in the barrel. I used the orginal sight, pins, and a pair of calipers to measure where the holes are. And I came up with this sketch. The boxed dimemsions are the numbers I had to hit. As you can see these dimemsions are not a standard. Probably all sight pins are slightly different.
My hole map:
Now I set the barrel up on the Bridgeport. I indicated it in with my indicator to make sure the barrel was zeroed out:
I used the machines digital readout to go to my numbers. The sight is curved right where the holes have to go. So I used a 1/8th end mill to create a flat in that area. I then used a small center drill to spot the area where the drill has to start.
1/8th end mill flat:
Next I drilled the holes. First I went with a .090 drill and then a .120 drill. I was sweating bullets at this time praying that my calculations were right. I knew even if the vector was off a little that was ok because the drill would follow the hardened barrel. That is why I went with smaller drills. The tapered hole on the small end had to finish at .126 and the large end had to finish at .140 So I used the smaller drills and then reamed by hand with my tapered reamer. And again the reamer just followed the hardened barrel making the hole a prefect taper. The reamer cut the sight to match the existing holes.
Drill hit the holes.........Yippie:
Then I just reamed by hand until I got the desired fit. The barrel is hard but the sight is soft so the reamer aligned itself. I pounded the pins in and all is good!!
It worked...........Yippie dippy doo!!
I will now close this subject. I'll bet you guys are glad of that hehe.