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Boring a stock bolt hole

8K views 16 replies 9 participants last post by  DK PHILLIPS In Memoriam 
#1 ·
Anyone know how they bore the hole in a gun stock to accept the bolt which threads into the reciever and get it true. Do you know anyone who does this
 
#2 ·
Inlet the receiver. Mark the bottom of the receiver where the hole for the screw is with inletting black, and press the receiver straight into the stock. Mark the center of the hole that shows up in the black inside the stock inletting.
Set up stock with receiver under a drill press, with the barrel level and straight. Remover barreled receiver, center marked, levelled stock under the bit, and drill the hole.

Same with the rear tang screw, except it may be at an angle.

Most modern rifles with wood stocks use a pillar inset in the hole to stop the screw from compressing the wood.
 
#3 ·
If you mean the thru-bolt that runs from the buttplate you need a drill press and a long bit. Drill a shallow hole in the butt end.
Put a piece of wood in the drill vice and with the drill bore a hole in it. Now if you put a pin in the wood block and put the
butt over it the drill has to come out right (if you have lived a clean life).
 
#4 ·
Gary, you need access to whats called a "gun drill", a horizontal bed which clamps the stock and has a half-round drill bit which can then be passed through the stock while having a shot of air injected into the hole to cool the bit and blow the chips out at the same time. These can be found in shops which do a lot of wood turning on lathes, spindle making, wood spools, etc., on a commercial level. Find a shop which caters to the woodworking trades and hobbyists, and they might be able to turn you on to one. Failing that, maybe you can find a mom & pop stock maker who would have the necessary equipment and would be willing so to do. I have access to a gun drill, but most of his bits are too small for your purpose.
 
#13 · (Edited)
As a retired machinist, I agree. A "Gun drill" is a cutter with two different angles ground on the tip so it supports itself as it advances. The shaft of the drill is a crimped tube to give it some rigidity and to allow coolant flow. You can silver solder a drill bit to an extension. I do that to make drills to install liners. This will save you from ordering the wrong drill.
 
#7 · (Edited)
There is a version used in the production of textile spindles which goes by the same name; I've used it numerous times to do woodworking projects. In Wikipedia's definition they make reference to the manufacture of woodwind instruments as a use for a "gundrill". No need to put a finer point on it as long as Gary gets the help he needs.
 
#8 ·
If its the long bolt as in shotguns and SMLEs, that's a whole other problem. If you have to ask I wouldn't try it as you'll need experience to rig up a jig, measure, mark, set it up and drill without wrecking the stock. You are much better off buying one or if you have a buttstock billet you want to use, have a stockmaker make it up at whatever level of finish or semi-finish you want.

Try
http://www.gunstocksinc.com/index.html
http://www.rifle-stocks.com/
 
#9 ·
Long wood drills are used for fencepost boring, are 12" to 18" and come in sizes from 1/4 to 11/2".
I wrote a comment on this yesterday in the Martini forum, maybe worth checking, disregard the follow up comment. I guess he doesn't realise we were talking about the same thing, just leaving out technical confusion.
 
#11 ·
heres what i observed on:
Iver Johnsons....they bored the holes from both side AND meet apex. in the pistol grip area where a larger chamber hole is present.

first if you look inside you will see the "inter section" of both drill holes a larger chamber ....
the difference of missed intersections is shaved off allowing the threaded rod to meet the holes passing up to the reciever.......

it is very difficult to drill straight through...know this factually....i have done more than a few of these..
my stocking friend hundereds....
the drill bits will follow the grain, or travel off course into the softer grains or sap wood....but you can get half way both ways meeting in the unknown middle....the meeting point is enlarged and rode will pass through correctly at the action if you measured center down back to rear....centered rear to intersection point...

this works every time.....not messing up blanks....or coming out way off center trying to go all the way in one direction!
hope this helps <><dk
 
#12 ·
Whatever you do, don't tell my stock boring jig that, I'd hate it to start doing weird things and not want to finish the job from one end.
That aside, it's how fast you spin the drill and how often you relieve it that allows deep hole drilling.
The only time I turn the butt is to do the counterbore.
 
#14 ·
if a bed-ing job came in done wrong ? What?...get it all the old out start over. ."building on over old work all guessing. Problems cost a lot more than just re do it! i like klengunther 3 point bed-ing, with slight 4-5 pound pressure tipping at for arm?
measured by scale lifting up on barrel to get a dollar bill slinging through at about 3#. 4#..
test at range then add or take away the upward pressures.
just my thoughts on it..im no expert only bed-ed 50# or little less.. only one defeated me 22 250!
later found it was a custom bullet of large dia?<>< Dan
 
#15 ·
on Iver Johnson's i discovered how they drilled the "bolt through hole" in two steps!
FIRST they drilled from the end touching steel, as far as the pistol grip area..
then at the rear they drill toward the other hole...
in the very middle its " hogged, wallowed out" so the through bolt lines up!
if you try with a press the bit still follows the easiest softest grain route ....?
my gun smith fought this idea till i had him work over two 410;s for grand kids stocking them fancy!
fancer the wood the more "stressing unstable problems fitting finishing!<><>Dan
-------o------- looks like this in middle of stock!
 
#16 ·
I've seen industrial set ups that do this, like a two headed lathe with a sliding carriage between the two heads.

In the small shop what you describe is very hard to do, long twist drills wander to a surprising degree, especially if the wood is nicely figured. A long step drill helps a lot if you have one. I've read about re-grinding twist drills to a multi-angle point, but I didn't have a lot of luck when I tried that. Set up for drilling each hole is also very difficult to get precise - between set up errors and the drill wandering you can be more than 1/8" off when the holes meet.

With pistol grips (like for a metric FAL, which is the kind of thing I do far more than buttstocks) it ends up being easier to spend the money on a sub-land step drill since they don't wander as badly in end grain wood and the holes are typically stepped anyway. Hard to find in buttstock lengths, but I bet something could be cobbled together like some of the older posts in this thread describe.

Fuller makes steeply tapered twist drills for wood screw holes, I wonder what the biggest one is? One of those on an extension could do pretty good, with such a pointy end they don't seem to wander like regular twist drills. Problem with them is you can't resharpen, the edge of the twist flutes does most of the cutting. Might work ok for custom makers though, could get several stocks out of the setup before the bit was too dull.
 
#17 ·
"between set up errors and the drill wandering you can be more than 1/8" off when the holes meet." well written and what i taught a skilled gun smith with the proper tools very difficult to track..
AAA walnut during fittings being stressed relieved...
will blow out chunks, or crack releasing the twisted grains!
old growth walnut trees.> grown in mineral rich soil..
the grains are so heavily mineral enriched ..
NEVER written in any book, nor ever said that ive heard..
this was possible
."A MAGNET WILL PICK UP grain wood DUST LIKE METAL!" !
ive done it, he showed me!
 
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