Redrill crooked scope mount holes

[bchannell]

I had some, so called, "gunsmith" (moron in this case) drill my MKII for scope mounting using the base Ruger supplies for Weaver mounts. He drilled the screw holes QUITE crooked, but the base is straight on the gun. I'll probably use it as is for a while, but it irks me that he screwed such a simple job up. Can the holes be redrilled from the current #6-40 to a larger size and clean up the mis-alignment? What size do you recommend?

What really burns me is, I drilled a couple of Ruger standard model guns for scope mounts and did fine, but this gun is no longer made and I didn't want to take a chance, so I went the professional route. What a mistake, next time I'm going out and buy the drill press and vise I've wanted for a long time and do my own work. I could have even taken it to work and used ours there, I just wanted it done right.

 

[DGW1949]

Sorry for your mis-fortune. I been in that situation myself. And like you, decided long ago that I could do a better job on most things, than most of the so-called "gunsmiths" that I've seen over the years. Providing of course, that I have access to the equipment it requires....which most back-room "gunsmiths" aint got themselves.

Far as your questions, here's my take on things....

The diameter of the straight hole required to do away with the crooked hole is going to depend on how crooked the first holes are.
Having said that though, there's quite a bit of difference in a #6 and a #8, which the next (US) size up.....so that's the one I'd try first.
Fas as thread-pitch goes, gun screws are typicly much "finer" than commonly available fine-thread machine screws, like ya get down at the hardware store....so the tap you use is going to depend on whatever screw-pitch you have available to you. And don't be surprized if you end-up with a choice of screws which are either too short or too long...which means you'll need to shorten a long one.....More fun, heh?

The type of repair you are wanting to do is best done on a Bridgeport...and with either a very short bit, or a boring mill. Reason is...(as a rule) when you're working with something that small, a longish bit mounted in a drill press is going to try real-hard to follow the old hole.
Be aware also, that by going to a larger mounting screw, that you'll probably have to redrill the holes in the mount itself...and also the counter-sink....Because the larger screws aint likely to fit into an area sized for the smaller screws.

I don't know if Helicoils are available in 6-40 or not. But if they are, that might be another option.

Or....being's how the mount is sitting straight, you can always just use it as-is.
Reason I'm saying that is....it's always harder to fix a bad job, than it was to do the job...and if you aint got the right stuff to fix it, there's always the chance that it could get worse.

That's all I know about that.

DGW

 

[Enigma]

One option is to have the holes welded up by a competent gunsmith or welder, and then redrilled. Alan Harton has been recommended for welding up screw holes before, and I'll wager that he could also drill and tap the holes straight, and in the right locations.

 

[Pinecone]

bchannell, What DGW1949 says carries a lot of "wisdom"! Since the base "is" in line with the bore, I would see how it "shoots first" before doing anything else. As a gunsmith for many years, I have spent a lot of time fixing other peoples screw-up's than if I had gotten the job first to begin with! Even though retired from the business, I still do a lot of work for friends and relatives and am in fact right now re-doing a single shot .22 for a cousin for his grandson that was literally "butchered" by a previous owner. For my money, the Forster Sight Jig has been one of the best tools in my shop for the many years I have had it. It puts the bore in line with the sights or scope mount for drilling and tapping and the jig bushings prevent drill bit "walking" or canted tapping! It pays to "check" out a gunsmith before giving him your work to do. Simply ask for references of his work and what equipment he has to do the job your interested in having him do. If he hedges at all, you know your in the "wrong" place already! Local gun shows are a good place to get "scuttlebutt" on area gunsmiths good or bad. The best way to usually correct off center holes is the "weld-up" route and get them drilled and tapped properly by a bonified "professional".........................Dick :wink:

 

[bchannell]

Well, for now it's ok to shoot and I've not decided what I'll do. How do I contact Alan Harton?

Thanks for all the advice, it's always a wealth of knowledge. I actually have heard of this 'smith for quite a while, but never needed his services, as I usually do it myself, but every once in a while, you want to have something done by a pro and not have to stress over doing it yourself. My mistake. I aksed a couple of friends and they had heard some good things about his work, and I honestly thought is was such a simple job it would be one of his easier tasks. I mean, really, if you can't get this right, then how on earth would you do complicated work? But, lesson learned. I've already got the boring mills at work, so if I could just get the holes welded up, I think I could make the required repair, but as I said, I haven't decided to do anything yet.

More than anything else, I look at guns differently than most and can't stand to see some butcher work on them. I usually do most of my own work on them because I'm so particular. Wanna hear the real kicker? Wayne Novak's shop is less than two miles from my house, and he does work that will amaze even the best gunsmith, but I figured he was too busy for this type of work, and I'd have to wait for weeks to get it done!!!

 

[Enigma]

Well, for now it's ok to shoot and I've not decided what I'll do. How do I contact Alan Harton?

[email protected]

 

[corelokt]

I invest in a Forster scope and sight jig just to prevent this. Between that and my little mill, straight holes happen in the right places.

truedblued.com

 

[RoninPA]

You can get everything you need to do your own scope mounting (jigs, taps, screws, etc.) from Brownells. I'll also vouch for the Forster jig. Best money I spent for mounting scopes. Same with the jig for marking and drilling the holes for sling swivels.

 

[caryc]

If you don't have a jig to drill straight holes with, a set of center drills is cheap and will drill a nice pilot hole without any "drill bit walking".