I recently asked the owner of a local gun shop about tapping a firearm for scope mounts. He refused, in no uncertain terms, to drill and tap any firearm. He said it is impossible to know how hard the metal is. He has been in the business for a very long time and thus I was puzzled by his response. Is that procedure really that complicated? I understand that it would all have to be aligned properly in a non-marring vice, but to a gunsmith, I wouldn't think this would be rocket science.
drilling and tapping for scope
- Thread starter AL45
- Start date
Gunplummer
New member
Take it somewhere else, the guy obviously has no experience with scope bases or does not have the machinery to do it.
You did not mention what rifle you wanted drilled and tapped, the smith did qualify his answer by saying there is no way to determine how hard the receiver was. A better answer would have been "No I do not because? I have had a few bad experiences, or no one wants to pay for the labor/time/equipment.
Long before the Internet gun manufacturers were crating problems for someone planning to drill and tap a receiver. Before the Internet there were smiths that never considered the hardness of the receiver. Most had shop skills, they made tools for tapping hard receivers.
Then there was Roy Dunlap, when writing about his preference when selecting a receiver he but the M1917 Remington at the top of the list because it did not have an oval hole in top of the rear receiver ring. His second choice was the M1917 Winchester because it had the oval hole in the top of the rear receiver ring. And third was the Eddystone, he claimed he never knew what he was getting into when he started on an Eddystone. Drilling and tapping did not slow him down because he had shop skills.
F. Guffey
g.willikers
New member
Better to be refused than have your gun messed up.
At least the guy was honest with you.
Beware of anyone who will tackle anything, whether they know how or not.
At least the guy was honest with you.
Beware of anyone who will tackle anything, whether they know how or not.
Your dealer made a good call, be thankful !!
By the way, that Smith that I took it too, is now CEO of a firearms manufacture. .....
Be Safe !!!
It surely can be complicated and give your dealer/smith, credit for knowing his limitations. There are Smiths who are that, in name only and then there are real Craftsman. I can tell you from personal experience that I have encountered both. Years ago, I took a rifle that had been previously drilled and tapped by a "so-called" smith, to a real Smith. Just by holding and looking at the rifle, the new Smith, just shook his head and told me to come back in a week. He actually took on a bad job and made it shine. .....
By the way, that Smith that I took it too, is now CEO of a firearms manufacture. .....
Be Safe !!!
Easy to do.
Mandrel that fits the receiver and holds it center on a mill.
Dial off each end of the mandrel to find the center.
Touch off on the top of the drill.
Drill down to desired depth (avoid going all the way through).
Tap using a tapping center held in the spindle.
Finishing tap.
Bill client.
Mandrel that fits the receiver and holds it center on a mill.
Dial off each end of the mandrel to find the center.
Touch off on the top of the drill.
Drill down to desired depth (avoid going all the way through).
Tap using a tapping center held in the spindle.
Finishing tap.
Bill client.
I have seen it done on a milling machine, but I always used a jig. Hardness can be a problem (Model 1903's and 1903A3's are a b****) but carbide drills and taps were made to take care of that problem. If necessary, the receiver can be spot annealed.
Going all the way through is no problem on the rear ring or if into the receiver behind the barrel; it is only a problem when you could drill into the chamber, not a real good idea, as in you buy the customer a new barrel or a new rifle.
At one time, drilling and tapping was a big part of any gunsmith's business, but for roughly 65 years most rifles have been drilled at the factory and some gunsmiths have never been called on to do that work and don't know how to begin.
Jim
Going all the way through is no problem on the rear ring or if into the receiver behind the barrel; it is only a problem when you could drill into the chamber, not a real good idea, as in you buy the customer a new barrel or a new rifle.
At one time, drilling and tapping was a big part of any gunsmith's business, but for roughly 65 years most rifles have been drilled at the factory and some gunsmiths have never been called on to do that work and don't know how to begin.
Jim
Dixie Gunsmithing
Moderator Emeritus
You can do them on a drill press in a jig, or even using a vise with a two-stage table mounted under it. This makes it similar to a mill.
I always found the edge using a wiggler, then moved the quill over to center by adding 1/2 the wigglers button thickness to 1/2 the receiver thickness. The receiver must be mounted plumb and level in the vise. I then spot drill the holes, (a minor spot), using a carbide center drill, then finish with the required tap drill. Last, I have a spring loaded tap guide for the mill or drill press quill, which allows you to go straight with the threads, and not break a tap as easily.
Jim is correct, in that one that is through hardened, can be spot annealed, without harming the receiver. Also, breaking the surface of a receiver that is case hardened, is easily done by spot drilling with a center drill. Here, you're getting a starter hole that the bit will easily follow, in softer metal.
I always found the edge using a wiggler, then moved the quill over to center by adding 1/2 the wigglers button thickness to 1/2 the receiver thickness. The receiver must be mounted plumb and level in the vise. I then spot drill the holes, (a minor spot), using a carbide center drill, then finish with the required tap drill. Last, I have a spring loaded tap guide for the mill or drill press quill, which allows you to go straight with the threads, and not break a tap as easily.
Jim is correct, in that one that is through hardened, can be spot annealed, without harming the receiver. Also, breaking the surface of a receiver that is case hardened, is easily done by spot drilling with a center drill. Here, you're getting a starter hole that the bit will easily follow, in softer metal.
Folks who like to use a mill claim that it is more accurate than a jig; I am not sure how. All I know is that I never had any complaints and when I put the scope on I never had any trouble zeroing it.
But a lot of guys wouldn't pay the freight and I heard a lot of stuff like, "My cousin Pete owns a garage and he has a drill press and he will do it for nothing so why should I pay...." Sometimes I saw "Pete's" work, usually when the guy came back in wanting to know if I could plug up the crooked holes and start over. Sometimes I could, but the cost was a lot more than it would have been just to do the D&T job right.
Jim
But a lot of guys wouldn't pay the freight and I heard a lot of stuff like, "My cousin Pete owns a garage and he has a drill press and he will do it for nothing so why should I pay...." Sometimes I saw "Pete's" work, usually when the guy came back in wanting to know if I could plug up the crooked holes and start over. Sometimes I could, but the cost was a lot more than it would have been just to do the D&T job right.
Jim
Dixie Gunsmithing
Moderator Emeritus
Jim, those Forster jigs are pretty accurate, and in reality, one can use a hand drill with them. If I had a minimum amount of tooling, that is what I would want for scope mounting.
For those reading, the jig can be found here:
http://www.forsterproducts.com/store.asp?pid=24833
For those reading, the jig can be found here:
http://www.forsterproducts.com/store.asp?pid=24833
Gunplummer
New member
Not my favorite way, but I have clamped a piece of flat stock on a drill press table and used that for a backing of my small vise. I then use a long stroke dial indicator to set the vise before clamping. I am also a fan of bluing and marking. Even with a mill, something can go wrong, and the scribe marks make it obvious.
"...said it is impossible to know how hard the metal is..." Isn't exactly true, but some rifles are known for being very hard. Mini-14's for one. They'll eat carbide drills.
However, refusing to do any firearm is more of a lack of skills or equipment indicator. Not all gun shop owners are smithy's. Some of 'em just shouldn't be too.
However, refusing to do any firearm is more of a lack of skills or equipment indicator. Not all gun shop owners are smithy's. Some of 'em just shouldn't be too.
Dixie Gunsmithing
Moderator Emeritus
Funny he would say that, when we're all taught how to do it, and the factories do also. A revolver is a little different, but it has been done.
My first guess was that he thought it might weaken the top strap, but when he says 'any', well, I don't know why.
