The Firing Line Forums

Go Back   The Firing Line Forums > The Skunkworks > The Smithy

Reply
 
Thread Tools Search this Thread
Old March 12, 2012, 02:19 PM   #1
meatgrinder42
Senior Member
 
Join Date: July 1, 2011
Location: Good Ol' Wisconsin
Posts: 327
Drilling and tapping for a scope

I have a sporterized 1891 Argentine with a great bore I use for deer hunting. I want to be able to mount a scope on it without using a LER. I'm not a stranger to drilling and tapping from doing automotive work so that doesn't concern me. What I'm wondering is were exactly do you place the holes on the receiver?
__________________
When I die better bury me deep, two .45s layin' at my feet,
An M16 across my chest, tell Chesty Puller I did my best
meatgrinder42 is offline  
Old March 12, 2012, 04:21 PM   #2
mapsjanhere
Senior Member
 
Join Date: August 6, 2009
Location: Albuquerque
Posts: 2,832
Where they are needed . Buy the correct mounts for your receiver, find the centerline, position the mounts, center punch through the holes in the mount.
__________________
I used to love being able to hit hard at 1000 yards. As I get older I find hitting a mini ram at 200 yards with the 22 oddly more satisfying.
mapsjanhere is offline  
Old March 13, 2012, 10:02 AM   #3
PetahW
Senior Member
 
Join Date: September 19, 2008
Posts: 4,678
[were exactly do you place the holes on the receiver?]

Everybody, except Bubba, uses a drilling jig of some kind, like the Forster or B-Square, to ensure the holes are plumb/square with the receiver's bottom flat AND in the correct location(s).

.
PetahW is offline  
Old March 13, 2012, 01:47 PM   #4
James K
Member In Memoriam
 
Join Date: March 17, 1999
Posts: 24,383
The way some folks describe it as being so simple (no jig, no milling machine, no drill press, just scribe a line and have at it with the handy 1/4 inch hand drill), I wonder why so many people mess up.

I have drilled and tapped a lot of receivers and I wouldn't try it without a jig (though there are exceptions, like a side mount).

Jim
James K is offline  
Old March 14, 2012, 01:53 AM   #5
edward5759
Senior Member
 
Join Date: September 15, 2009
Location: Phoenix, AZ. 30 miles from water, two feet from Hell.
Posts: 355
1891 Argentine should be a flat bottom receiver.
Use your calipers as accurate jaws to hold your mount on the top of the receiver to get center position after you remove the loading hump.
This link should help. I use this method on Mexican, Argentine, Spanish, Turkish, and others.

http://www272.pair.com/stevewag/turk/turkscope.html
__________________
Failure is part of success!

This year will go down in history. For the first time, a civilized nation has full gun registration. Our streets will be safer, our police more efficient, and the world will follow our lead into the future!" -Adolf Hitler,1935"
edward5759 is offline  
Old March 14, 2012, 09:57 AM   #6
meatgrinder42
Senior Member
 
Join Date: July 1, 2011
Location: Good Ol' Wisconsin
Posts: 327
I have never seen a drilling jig for an 1891 Argentine Mauser... I've seen them for the K98/large ring. Also I've seen the cost for said drilling jigs... And not being a gunsmith it's hard to justify buying a hundred dollar jig for one receiver, one time...

I wouldn't be tackling this ordeal with a 18v Milwaukee or anything like that. I have access to a drill press I would use if I knew exact hole placement for the mounts.
__________________
When I die better bury me deep, two .45s layin' at my feet,
An M16 across my chest, tell Chesty Puller I did my best
meatgrinder42 is offline  
Old March 14, 2012, 02:31 PM   #7
James K
Member In Memoriam
 
Join Date: March 17, 1999
Posts: 24,383
If you can't use a jig, then you can try this.

Get some clamps.

Clamp the receiver solidly to the bench or in a vise. Use a machinists level on the bottom of the receiver to make sure it is level.

Clamp the mount base to the front receiver ring. Check to see if one hole, if drilled too deep, will go into the chamber. If so, make note of that.

Put the machinist's level crossways on the top of the mount. Move the mount base until it is perfectly level. Center punch through one of the base holes, lightly. Double check everything, including using a long straight edge in place of the level. Triple check. Twice.

Then center punch the other base hole. Double check. If all looks good, including by eyeball (it is surprising how accurate a trained eyeball can be), center punch normally and drill ONE hole in the drill press. MAKE SURE you don't drill too deep and drill into the chamber.

Screw down the front base with one screw and mount the scope with just the front base. Set the rear base in place and try the scope. (You are checking for mismatched bases before going any further.) Double check, etc.

If all is OK, remove the scope and the front base, and drill the other front base hole. Double check. Again. If all is OK, repeat the process with the rear base.

Make sure the bolt works; if not, you might have drilled into the bolt lug area behind the chamber and the screw is blocking the bolt from turning, or a rear base screw might be keeping the bolt from going into place. If so, remove the offending screw and shorten it until the bolt clears it. (Do not grind off the locking lug to clear the screw, as I heard of one fellow doing.)

Lotsa luck!

Jim
James K is offline  
Old March 14, 2012, 02:33 PM   #8
mapsjanhere
Senior Member
 
Join Date: August 6, 2009
Location: Albuquerque
Posts: 2,832
Do not grind off the locking lug to clear the screw, as I heard of one fellow doing

Thanks, you just made my day.
__________________
I used to love being able to hit hard at 1000 yards. As I get older I find hitting a mini ram at 200 yards with the 22 oddly more satisfying.
mapsjanhere is offline  
Old March 15, 2012, 08:10 AM   #9
meatgrinder42
Senior Member
 
Join Date: July 1, 2011
Location: Good Ol' Wisconsin
Posts: 327
Thanks James!

Quote:
Do not grind off the locking lug to clear the screw, as I heard of one fellow doing
Made hot coffee come out my nose... thanks...
__________________
When I die better bury me deep, two .45s layin' at my feet,
An M16 across my chest, tell Chesty Puller I did my best
meatgrinder42 is offline  
Old March 15, 2012, 06:27 PM   #10
Fleet
Senior Member
 
Join Date: December 1, 2011
Posts: 108
To amplify what James K said...as most people aren't familiar with a machinist's level, the thickness of a piece of paper will throw the bubble completely off the scale. See this: http://www.starrett.com/metrology/me...hinists-levels
The cheapest route here is to take it to a gunsmith, and yeah, it may cost a few bucks for him to do it. But his cost to do it will be much cheaper than his cost to fix what you screwed up by not having the proper tools. This assumes that it IS repairable.
Fleet is offline  
Old March 15, 2012, 06:56 PM   #11
James K
Member In Memoriam
 
Join Date: March 17, 1999
Posts: 24,383
I usually recommend a gunsmith but some folks just insist they want to do it themselves, without spending money on a jig. The method I described will work.

If the idea of grinding the lug to clear the screw results in coffee in the nose, how about the "gunsmith" who didn't know about short chambered barrels, so he ground the back off the locking lugs. When questioned, he didn't understand what he did wrong, as the headspace checked OK with the gauges. Of course the back of the cartridge case would have gotten a bit cold, sticking out in the air like that, but what the heck. (Fortunately, someone else checked the rifle before the customer fired it.)

Jim
James K is offline  
Old March 16, 2012, 08:22 AM   #12
meatgrinder42
Senior Member
 
Join Date: July 1, 2011
Location: Good Ol' Wisconsin
Posts: 327
I am familiar with the machinist's level and own one (use it for checking heads and engine block decks).

I have been considering a gunsmith but I enjoy doing this kind of stuff. I'm the same way about my cars... I don't let anyone else touch them... The thought of another man/woman with their hands all over my Z28's engine makes me shake.

James K: That one didn't make the coffee go... but it did make the head shake.
__________________
When I die better bury me deep, two .45s layin' at my feet,
An M16 across my chest, tell Chesty Puller I did my best
meatgrinder42 is offline  
Old March 16, 2012, 07:36 PM   #13
Harry Bonar
Senior Member
 
Join Date: December 5, 2004
Location: In the Vincent, Ohio general area.
Posts: 1,804
drill&tap

Sir;
The best base for the Mauser is the Redfield one piece base for the military mauser - you don't need to recontour the rear ring that way.
Harry B.
Harry Bonar is offline  
Old March 17, 2012, 07:34 AM   #14
Goatwhiskers
Senior Member
 
Join Date: April 8, 2009
Location: Batchelor, La.
Posts: 579
To add to James K's procedure, I would highly recommend using a one piece base, further reduces the chance of error. I know some people don't like 'em but accuracy is paramount. Goat
Goatwhiskers is offline  
Old March 18, 2012, 09:04 AM   #15
HankC1
Senior Member
 
Join Date: April 4, 2005
Location: Ohio
Posts: 531
Some folks use hot glue to help holding the base for drilling. I used super glue and then cleaned it. Hot glue maybe a better way to go and easier to clean. Bore sight before drilling. Once drilled, no return!
HankC1 is offline  
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -5. The time now is 08:34 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
This site and contents, including all posts, Copyright © 1998-2021 S.W.A.T. Magazine
Copyright Complaints: Please direct DMCA Takedown Notices to the registered agent: thefiringline.com
Page generated in 0.06583 seconds with 10 queries