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Dovetail slot (Read 2171 times)
plumloco
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Manassas ,VA, Virginia, USA
Dovetail slot
Jul 21st, 2011 at 7:49am
 
I Hvae a RB with a .375 front sight cut slightly unlevel. The bubble is just a bit to the left when the rifle is level. Is it possible to recut the same slot for a .450 base dovetail to level it out. And who would be able to do the job? (gunsmith?)
Thanks
out of Plum  loco
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Old-Win
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Re: Dovetail slot
Reply #1 - Jul 21st, 2011 at 10:13am
 
Before cutting a new dovetail slot and buying a new sight, there are several things you can do. First, how do you know that the dovetail slot is off in the barrel and the problem is not in the sight??  If you have a sight that has a vial held in with two little caps, take one off and reverse the vial.  Any change? Next, reverse the entire vial with tube.  Can you shim one end of the tube with a small piece of electrical tape that could raise that end of the tube? Next, you could pull the forearm off and check for a witness mark.  Does the one on the receiver match up with the one on the barrel? You can also check the barrel by looking at the extractor cut and seeing if the space is uniform top to bottom.
If none of this works, and it were mine, I wouldn't worry too much about whether the bubble is plumb with the receiver but to have it plumb with the rear sight. You can shim the rear sight so that everything is as it should be. Unless it is really cut wrong, you and the gun will never know the difference. Uniformity from shot to shot is the key. Bob
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plumloco
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Re: Dovetail slot
Reply #2 - Jul 21st, 2011 at 10:44am
 
Thanks Old-Win.  I will try some of the things you have mentioned.
The dovetail was cut with the barrel loose. Once the barrel was tighten
The sight was off. The extractor lines up. The guns shoots well when i shoot with out looking at the bubble. Again! I'll try the things suggest and see how they work. Thanks
Plumloco
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38_Cal
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Re: Dovetail slot
Reply #3 - Jul 21st, 2011 at 2:11pm
 
Other ways to check: level the rifle in a padded bench vise using a machinist's level.  Check the sight level.  Remove the front sight and check that the rifle is still square to the world.  Place a 5/16" square high speed steel lathe bit into the sight dovetail and then the machinist's level onto the lathe bit.  Or, lay a similar lathe bit across a flat section on the action top and sight from a few feet away at both lathe bits.  If the dovetail is off even a couple of degrees, you'll see it!  If the dovetail checks out then you've got a problem with the sight or the level in it.

David
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David Kaiser
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plumloco
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Re: Dovetail slot
Reply #4 - Jul 22nd, 2011 at 12:09pm
 
Thanks .38cal. The slot was checked after the barrel was tightend. The slot is not level. I don't have access to any of the tools you have mentioned. That's why I was looking for a gunsmith to do the job. I'm going to try some of the Old-Win things this weekend. If one works? I will post the results. Thanks for the help.
Plumloco
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Old-Win
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Re: Dovetail slot
Reply #5 - Jul 22nd, 2011 at 5:17pm
 
If you decide you are going to try and recut the dovetail, take a reading on the depth of the current cut. Some smiths will cut it .100" and some around .090" deep.  If it's a shallow cut, you will probably be OK trying to clean it up with a new .450" dovetail as you can go a little deeper.  Take a reading on the depth of the male part on your new sight and make sure you have enough for clearance or you might have to file a flat on top of your barrel to get it to slide on.
Double check the clearance around your extractor as it sounds like the barrel may have been over tightened unless it wasn't indexed properly. You could back it off a degree or two and it may make a big difference and the extractor could still clear.
Another thing that I would try first would be to get a safe triangular file and take a little metal off the inside of the dovetail and then you could shim the underside of the sight to raise one side up.  Bob
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Mike_Hunter
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Re: Dovetail slot
Reply #6 - Jul 23rd, 2011 at 8:34am
 
Lots of good advice, definately check indexing as Old Win sugested, you might be able to tweek it some and all your problems will go away. Simplest solution is often the best.

Recutting should be left to a smith who knows what he is doing; if it wer in my shop,I would square up the frame in the mill, then check the DT cut with a .0005  Test Indicator, might just need running the cutter thru at the correct angle to remove 3-4 thous from one side of the DT.

Worst case, on extreme repairs, I've had good luck by silver soldering a DT blank in place, then remachining the DT cut... very hard to see if done correctly.

V/R

Mike

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Chuckster
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Re: Dovetail slot
Reply #7 - Jul 24th, 2011 at 10:12pm
 
Mike,
Good solution. Are you comfortable silver soldering (silver brazing) parts on a barrel or do you do something to protect the bore from scaling? Have done it both ways and don't see much difference if you don't overheat, but concerned.
Chuck
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Mike_Hunter
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Re: Dovetail slot
Reply #8 - Jul 25th, 2011 at 12:04pm
 
Chuck

I actually dislike heating barrels at all, but it all depends on use and intent.

I've repaired extra dovetails/cuts in barrels by making a tight fitting plug then using a product called Black Max (by permatex) it's a super super glue. I've also done "shrink fit" repairs,  where I will make a plug slightly larger than the cut .0005-.002 and by heating one part, and chilling the plug, you can put the plug into the hole/cut and when they hit room temp, an extremely tight joint and very hard to detect.


For repairing a sight dovetail that will have a sight installed and not removed, using a soft solder will suffice, I've even used very soft plumbers solder.

For sights that will be moved or removed (changed) often... softer solders may not hold up, the only option would be silver brazing or TIG welding.

A brass/AL rod in the bore with some heat stop  will protect the bore, but my biggest concern would be warpage, by heating only one small section of the barrel.

Keep in mind... these are repairs to an already boogered barrel. For the perfectionist I would recommend having a new barrel made correctly or dont buy barrels with problems.

V/r

Mike

Mike Hunter
WWW.HunterRestorations.com
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Chuckster
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Re: Dovetail slot
Reply #9 - Jul 25th, 2011 at 10:40pm
 
Mike,
Thank you. Good answer and very good information. My only question is the soft solder joint. A sweat soldered joint can be very stout and would do that for myself, but you are probably right. A silver soldered joint is better for other people.
Chuck
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