Countersink a tang hole

[Blacktail]

I'm trying to layout the hole location for my tang bolt between the tang and trigger plate. It seems like it will have to be angled to one degree or another depending on how far down the tang I drill the hole. How in the world does one properly countersink the screw once the hole is drilled? It looked scary so I spent some time last night practicing with wood scraps. Anything ninety degrees works fine, but angled and curved surfaces are no good! I'm not drilling anything until I can make sure it can be done correctly.

A search of the archives had a mention of using gimlets to make the countersink but no details. Any ideas?

[Mike Brooks]

Check here. http://americanlongrifles.org/forum/index.php?topic=31173.0

[Blacktail]

Very helpful all around, thank you. So basically the key is to angle the gun when mounted on the spike in the drill press so that the bit is 90 degrees to the tang and just have an angled hole through the trigge plate?. Minus an assistant, is it helpful to block up the gun in order to maintain the angle between portions of the operation?

[B.Habermehl]

I usually carefully layout both the entrance hole in the tang and the exit hole in the trigger plate. Making sure the resulting hole will be 90 degrees to the tang surface. Then center punch and drill a 5/64 pilot hole in the tang and trigger plate, eyeballing the angle. Check for center. Now set up the center to center jig on the drill press. Chuck the countersink in the drill press and countersink the hole first. If needed fudge the hole to one side or the other to get it perfectly centered in the tang. Now drill through the tang and trigger plate with the tap drill. Stop just short of your center tip. Finish the hole free hand with your hand drill. Go back to the drill press and drill the tang hole and stock with the clearance drill stopping at the trigger plate. Now tap the hole in the trigger plate  through the tang and stock, starting from the tang surface. BJH

[Eric Krewson]

90 degrees will be the optimum angle for drilling but being a newbie my first tang hole didn't go as planned.

I countersunk the hole after the fact by hand, every time I tightened the tang bolt my barrel moved up about .010. Repeated attempts to correct the countersink problem only made it worse to the point that I had the tang hole welded up to start over.

What I do now is set up my drill press with the gun on a drilling spike, drill the tang bolt hole, and while the gun is still in position I countersink at exactly the same angle as I drilled the hole, no more problems.

Of course the picture is after I turned the gun over to finish drilling the trigger plate but my tang bolt /countersink method is the same.

[Mike Brooks]

90 degrees will be the optimum angle for drilling but being a newbie my first tang hole didn't go as planned.

I countersunk the hole after the fact by hand, every time I tightened the tang bolt my barrel moved up about .010. Repeated attempts to correct the countersink problem only made it worse to the point that I had the tang hole welded up to start over.

What I do now is set up my drill press with the gun on a drilling spike, drill the tang bolt hole, and while the gun is still in position I countersink at exactly the same angle as I drilled the hole, no more problems.

Of course the picture is after I turned the gun over to finish drilling the trigger plate but my tang bolt /countersink method is the same.

That's how I do it. I'm not smart enough to use support, I just hold my tongue right and run the press with my right hand and hold the gun at the correct angle with my left... I live a little closer to the edge than most.

[Eric Krewson]

Those are bags of lead shot, they hold the gun very securely.

[Blacktail]

Thanks boys. I braced it with sandbags tonight and drilled the tang and clearance hole, then ran the countersink. The tang bolt head is off kilter by perhaps 1/16" but I reckon I can fix that with some careful countersinking and maybe taking the diameter of the bolt head down a touch.

[Curt Larsen]

I got tired of the drill press spike method and now just use one of Tom Snyder's tools for aligning pins.  I got him to make me a 3/32" for pins of that size the correct tap drill size for my tang bolts.  I drill pilot holes for my chosen tang and trigger plate locations and use a hand drill for the rest.  There are no problems with not having an assistant to hold the barrel or using a block.  It's just a one man operation.
Curt

[Mark Elliott]

I hate to admit this, but I drill the hole just like Mike; horrors!    As to the countersink,  I do that by hand (80 degree countersink in electric hand drill) making little adjustments as I go until I have it right.   Now that I have a good countersink bit for my brace,  I will probably use that.  It is just as easy;  Only a little bit slower for more adjustments. 

[JCKelly]

Drill press? Electric hand drill?

I find that for countersinking a hole a hand brack works just fine. One can control how much metal is being removed & adjust as one goes.

Power tools.

They move a lot of metal, and do it just the way they want.