fixing mis-drilled holes
- Thread starter w_houle
- Start date
madcratebuilder
New member
This is really the best fix, any thing else is a band aid.
The best fix is to find an expert with a heliarc welder who can fill up the holes and use a heat sink (wet cloths) to keep the heat from affecting the barrel. Then redrill, using a jig or a milling machine. With a bit of luck if you are installing sights or a sight base, the work will be covered and you won't even have to reblue the barrel.
When I was working as a gunsmith, we got that problem about once a month, as people who didn't want to pay for a proper drill and tap job used a hand drill or tried to have it done at a local garage.
P.S. JB weld won't hack it.
Jim
When I was working as a gunsmith, we got that problem about once a month, as people who didn't want to pay for a proper drill and tap job used a hand drill or tried to have it done at a local garage.
P.S. JB weld won't hack it.
Jim
grymster2007
New member
Yup; TIG weld them up, then re-drill in proper location. Tapping, then plugging with a screw would likely work also. I'd avoid JB Weld.
Maybe someone can enlighten me, but what is it with JB Weld? I have used it and it is just another glue with metal in it, like a half dozen others. It is absolutely NO substitute for welding in any situation requiring any strength.
But for some reason, folks attribute to it some kind of magic. I remember one poster who had a barrel crack and was advised to use JB weld to hold in 40 or 50 k psi!
Those epoxies and "welds" are fine in their places but they are not hardened steel. They will drill and tap, but the threads won't hold under any significant strain.
Jim
But for some reason, folks attribute to it some kind of magic. I remember one poster who had a barrel crack and was advised to use JB weld to hold in 40 or 50 k psi!
Those epoxies and "welds" are fine in their places but they are not hardened steel. They will drill and tap, but the threads won't hold under any significant strain.
Jim
grymster2007
New member
Bingo, Jim. I tried it a couple times as a young pup, but found no good use for it. I like metal.... real metal.
I agree the JB idea is not good.When it doesn't work,it makes life harder for your tig meister.
I would also agree with a toolmaker grade tig expert being one good option.
I will offer another option.The end result you want is a base screwed on the gun,and the hole in the base does not line up.It may be easier to move the hole in the base to suit the hole in the receiver.
There are a number of ways to do this,from blank gunsmith bases to milling the base to accept an insert to welding the hole in the base.
Myself,I think I would avoid more trauma to the rifle if you have a good tapped hole.Is it possible this was done on a mill with the old reverse backlash,or .100 error,or a slipped dial? Maybe the hole is centered on the action,in line,(y axis) but an error occured in the x-axis?.
You can try 2 or 3 times on bases,till something works,without doing anything more to the rifle.
I would also agree with a toolmaker grade tig expert being one good option.
I will offer another option.The end result you want is a base screwed on the gun,and the hole in the base does not line up.It may be easier to move the hole in the base to suit the hole in the receiver.
There are a number of ways to do this,from blank gunsmith bases to milling the base to accept an insert to welding the hole in the base.
Myself,I think I would avoid more trauma to the rifle if you have a good tapped hole.Is it possible this was done on a mill with the old reverse backlash,or .100 error,or a slipped dial? Maybe the hole is centered on the action,in line,(y axis) but an error occured in the x-axis?.
You can try 2 or 3 times on bases,till something works,without doing anything more to the rifle.
grymster2007
New member
If'n ya can stand knowing that the hole is off location.
madcratebuilder
New member
I wouldn't hesitate TIG'ing a hole in the receiver, but I would be very careful about TIG welding a hole in the barrel. No matter how well you control the heat you well effect the grain structure of the steel.
There are several alternatives, including working over the base. If only one hole has been drilled, you can simply move the base so the old hole is covered and re-drill. This gets trickier if all the holes have been drilled crooked because the rifle barrel/receiver will look like swiss cheese if the base is removed.
Another possibility is using a different base with different hole spacing. Just inserting a screw and redrilling will usually work if you are using a milling machine or a very stiff jig and if the screw is soft and the drill is stiff. Otherwise, the drill will try to follow the edge of the screw, with bad results.
If this is a personal project, anything goes that works. But a professional gunsmith has a problem. If someone else did the work, he needs to have a talk with the customer and discuss options. If he goofed, the best thing is to fess up and offer to repair or even replace the gun.
I remember a Winchester Model 71 (.348 Win.) that came in for sighting in. I happened to notice what looked like the edge of a hole peeking out from under the side mount. I asked the customer to wait while I pulled off the mount. There must have been at least 15 holes in that receiver! The "gunsmith" who put it on couldn't get it sighted in, so he moved the mount, still couldn't get it sighted, and so on. The customer finally took it back and brought it to us to sight in.
The last I saw of the customer, he was going out the door, red-faced and steaming, headed for the other shop. I never heard of that gunsmith being murdered, so I guess it didn't get that far, but it does illustrate what not to do and not to panic and start doing irreversible things.
Jim
Another possibility is using a different base with different hole spacing. Just inserting a screw and redrilling will usually work if you are using a milling machine or a very stiff jig and if the screw is soft and the drill is stiff. Otherwise, the drill will try to follow the edge of the screw, with bad results.
If this is a personal project, anything goes that works. But a professional gunsmith has a problem. If someone else did the work, he needs to have a talk with the customer and discuss options. If he goofed, the best thing is to fess up and offer to repair or even replace the gun.
I remember a Winchester Model 71 (.348 Win.) that came in for sighting in. I happened to notice what looked like the edge of a hole peeking out from under the side mount. I asked the customer to wait while I pulled off the mount. There must have been at least 15 holes in that receiver! The "gunsmith" who put it on couldn't get it sighted in, so he moved the mount, still couldn't get it sighted, and so on. The customer finally took it back and brought it to us to sight in.
The last I saw of the customer, he was going out the door, red-faced and steaming, headed for the other shop. I never heard of that gunsmith being murdered, so I guess it didn't get that far, but it does illustrate what not to do and not to panic and start doing irreversible things.
Jim
longrifles Inc
New member
Tig the holes.
A MIG will do it as well. When at Nesika we'd have an occasional woops during barrel engraving (using a 4axis CNC) by having a bad offset and it'd result in a carbide center drill committing suicide.
A quick zap and sizzle and five minutes with a file and a belt sander saved the day. Never saw any difference on paper either.
Cheers and good luck.
Last note. If you intend to blue it, then you will see the spot because of the difference in material from the filler rod/wire. Just be aware.
A MIG will do it as well. When at Nesika we'd have an occasional woops during barrel engraving (using a 4axis CNC) by having a bad offset and it'd result in a carbide center drill committing suicide.
A quick zap and sizzle and five minutes with a file and a belt sander saved the day. Never saw any difference on paper either.
Cheers and good luck.
Last note. If you intend to blue it, then you will see the spot because of the difference in material from the filler rod/wire. Just be aware.
madcratebuilder
New member
Apparently I'm overly concerned about the heat issue. I can't say I have ever did any welding on a barrel and you folks have much more experience that I do. I guess I won't hesitate to fix any boo-boo's I do.
Hole repair
I owned my own highly precision Engineering and Manufacturing business for 25 years so I feel I know of what I speak. Do not even think of JB Weld do not weld in any way. Either modify the mount or Drill a larger hole and plug it. Then drill the hole inside the plug where it belongs. Just friendly advise. Dan
I owned my own highly precision Engineering and Manufacturing business for 25 years so I feel I know of what I speak. Do not even think of JB Weld do not weld in any way. Either modify the mount or Drill a larger hole and plug it. Then drill the hole inside the plug where it belongs. Just friendly advise. Dan
The one and only time in my whole experience in the shop that I ever had an extra hole in the wrong place(due,of course,to "concurrent engineering")
All I did was put in a plug screw,get out the letter stamps,and stamp OIL next to the hole.No problem.
I recall a friend adapted a Ruger 1/4 rib to another single shot and had to move some holes a bit.He bored thru the base on the new location with an end mill large enough to clean the off location hole,then counterbored the hole.He made a shouldered bushing to press in the new hole,complete with a hole and counterbore for the screw.It looks fine and works well.
I have seen some pretty amazing welding done in the bizz of moldmaking.
The word "microwelding" comes to mind.There is an outfit in Wisconsin saved my heinie once,but I don't know their name.
All I did was put in a plug screw,get out the letter stamps,and stamp OIL next to the hole.No problem.
I recall a friend adapted a Ruger 1/4 rib to another single shot and had to move some holes a bit.He bored thru the base on the new location with an end mill large enough to clean the off location hole,then counterbored the hole.He made a shouldered bushing to press in the new hole,complete with a hole and counterbore for the screw.It looks fine and works well.
I have seen some pretty amazing welding done in the bizz of moldmaking.
The word "microwelding" comes to mind.There is an outfit in Wisconsin saved my heinie once,but I don't know their name.