Drilling and tapping

[SKS Ray]

I have an SKS that i've been wanting to add a scope mount to for a while now. I won't post any pics of it with the aftermarket stock because i'm sure most of you have seen it in the milsurps section or gallery. I've seen a lot of receiver cover mounts and have always heard about people not being completely satisfied with them so after reading an article on a mount from Choate (the same company that made the stock I currently use on this rifle) I decided to buy one and try it myself.
Here is the link from Surplusrifle that gave me the idea http://www.surplusrifle.com/reviews/choatesksscope/index.asp
Now the whole thing sounds pretty simple, I've got all the recomended tools and I consider myself mechanically inclined enough to complete this project but have never drilled and tapped a rifle receiver and in the back of my mind am worried about screwing something up. I'm sure if I really mess up and get the holes way off I could always loctite some screws in there and grind them flush in the receiver, add touch up bluing and prtened it never happened (Saw that method on Midway's Gun Tech tv show) But this is one project I want to do right from the start.
So I ask you people reading... has anyone here drilled and tapped a receiver and if so are there any pointers not covered in the article I should know about?

 

[jhrosier]

Practice drilling and tapping a couple of holes in a piece of scrap steel.
If there is any problem with your technique, it will show up here.
Use a drill that just barely fits the screw holes in the mount to spot the holes before drilling with the tap drill. This will keep the holes precisely centered.
Champher the drilled holes about 1/64" larger than the OD of the screw before tapping. A 90 degree pointed tool is best, if you have one. This will greatly aid getting a clean start on the thread.
Use a tap guide to keep the tap exactly perpendicular to the receiver.
If you don't have one, make one. Even a piece of hardwood drilled just a hair larger than the OD of the tap will suffice for a few holes.
Turn the tap only 1/4 to 1/2 turn, then back it out a little to break the chips.
LOTS AND LOTS of oil for both drilling and tapping! It should take a couple paper towels to clean up the mess.
Nuthin' to it.

 

[SKS Ray]

Thanks for the tips. Sounds a lot better than heading into the workbench area and manning the dril press with a can of WD and a tap. Sounds like precision and patience is the key. I'll let ya know how it turns out with some pics and a range report when completed.

 

[BigBill]

It helps to drill a smaller pilot hole first after prick punching the desired location. I also like to scribe the hole thru the mount so i know the exact location of the hole before i start just incase the pilot drill walks a little off center we can go up one drill size and steer it back to were it needs to be by pointing the drill bit in the direction it needs to go and when its on center then drill straight in. If your drilling by hand. Three or Four flute taps are easier to start when hand tapping. Two flutes taps will wobble on you. It helps to chamfer the hole a little before tapping too this way the tap doesn't have that square edge to go thru plus it helps start the tap on center too. If you have the receiver clamped down on the drill press you can chamfer the hole and start the tap by hane using the drill press chuck to turn it by hand so its vertically lined up too Then take the receiver off the drill press after making 1 1/2 turns of the tap to start it and finish it by hand. It's just tricks of the trade with over 30 years of machine building.

I have tried the cover mounts with very poor results on my sks. I purchased the mosin mount from interarms for my mosin and liked how solid it is. I purchased a PKM mount and with a little cutting and welding I fabricated a solid sks mount using a mosin style scopemount. I drilled and tapped it lower on th esks receiver too more into the solid part of the receiver too below flush of the rail/receiver split line. I now have a scopemount on my sks that i(300lbs+) can hang on its that solid.

I have heard good things about the mount your using too anything that screws into the receiver and is solid is good with me. There are 3 good scopemounts for the sks, one is yours, the other is the mosin style mount and they use a AK rail(similair) on the 3rd style sks scopemount.. I seen the mosin style & AK rail mount in the yugo sniper sks section.

I was shooting with the cover mounted scopemount the very first time and on my last few shots while zeroing it in the dam scopemount came loose with those silly thumb screws that don't hold worth a dam. By did it get my onions going I just finished grouping right on the "X" and under a 1" group at 100yds with her when it came loose. Now i have to readjust her all over again but i know she can shoot accurately.

BTW; My search began for an sks scopemount that has nothing to do with the rear cover. I wanted to be able to disassemble and clean the sks without disturbing/upsetting the scopes zero. When i purchased my first sks cover mount there wasn't too much around in sks scopemounts. When it first malfunctioned i took the mount of and shot the sks with no scope for many years.

 

[SKS Ray]

What I like about the Choate mount other than being screwed directly to the receiver is that it allows use of the iron sights still, and from the shots in the article it looks like with some careful maneuvering i'll be able to take the receiver cover off for detailed cleaning w/out removing the mount.
I'm not worried about a good cheek weld because the Dragunov style stock I put on the SKS i'll be using has a removable cheek rest to add elevation or decrease it.
I think my biggest concern will be shells ejecting and barely clearing the compact scope i'll be using.

 

[BigBill]

Ok you need to get the vented handguard with the shell deflector. That will solve your problem before it starts. Thats the first thing i added after the scope on my sks. The only drawback is loading the mag so i purchased the detactable mags in 10rd, 20rd & 30rd. I like the detachable 10rd mag the best and all i would do is put a block of wood in it to hunt with it. Its very hard to load the orginal 10rd fixed mag with the scope and under the shell deflector.