Gunsmithing question: creating a new dovetail

[Aggiecubpilot]

After seeing Pete44ru's neat looking button magazine rifle I'd like to try to do the same. The only problem is my Rossi is an Interarms which has the front sight on the barrel band. So my conversion would require two dovetails, one for front sight post and one for a magazine hanger. Can this be done with files or am I going to have to hire a machinist and a mill? Pete if you could would you please chime in on how you did yours?

Thanks everybody

[Nate Kiowa Jones]

Sure, I've done more by hand than with the mill. I can do one dovetail by hand faster than I can set up the mill. Just lay it out where you want it, use a dremel and cutoff wheel to ruff it. Then use either dovetails files available from Brownells or take a small triangle file and grind one side smooth or safe. Use the file to finish trying for fit as you go.

[Pete44ru]

Gladly.

The hardest part is determining exactly where the centelline of the new dovetail slot will go, since you're generally going to work outwards in both directions from there until you have a 3/8" width (or whatever) female dovetail.

What should be done, is to make a square/level notch first, then expand the lower inside edges outward until a 45-degree female dovetail is achieved.

I apply a single layer of yellow masking tape to the barrel, and make my marks with a pencil, so I can so my mistakes.

Once the C/L is located, make a mark to either side of the centerline, equal to just UNDER half the measurement of the NARROW part of the male dovetail, of ther sight ot tenon that will be installed in the female dovetail. That will define to top of the open dovetail, once you're done, with an allowance for fitting.

Clamp the barrel, marks UP, in a vise, plummed so that the dovetail will be level across the barrel's width.

Make two vertical cuts into the barrel, one at each of the outer marks, to a depth just shy of the depth of the male dovetail you have, from the narrowest part down to the widest. Follow up with as many secondary cuts as you can between the first two, to remove the bulk of the "meat". (I use a hacksaw)

Now, clean up the area so that you end up with a square, LEVEL (side-to-side, AND front-to-back) recess in the barrel, that's almost as deep as the male dovetail of your sight, etc.

I then strart to cut into each sidewall, a little at a time, with a small triangular file held with one of the flats on the bottom of your recess.
Take care to keep from cutting into the floor of the recess with the bottom/flat of the file, while filing out the sidewalls to the 45-degree angle needed for the dovetail.
STOP, when the bottom/wide part of your filing starts to encroach upon the first two top marking you made earlier, and try the male dovetail for fit.

Now the fun starts - file a very little bit, try, file, try, etc - until the male dovetail starts to enter the recess. I would advise agains beating it in, since a good/tight fit can be achieved with some thought and careful filing/stoning.

Here's some pics to help explain:







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[pdawg.shooter]

Guess I have never seen a 45º dovetail. All I have ever cut have been 60º.

[Pete44ru]

Whatever...................

I've never actually measured one - I just fit them.

.

[rbertalotto]

Three sided file would be 60-60-60 = 180..........All dovetails I've ever seen are 60 degree.

I'm not sure I've ever seen a 45-45-90 file?

Nice work on the DT in any regard...............

[AJMD429]

Just remember the RULES:

• Go SLOWLY, and never start a complicated part when in a hurry or tired
  
  Measure two or three times, and visualize things before cutting
  
  Try to have FUN in the process - it's a HOBBY, not a job...

[kimwcook]

Thanks, Pete. That was very clearly explained and shown.

[Borregos]

Thanks, Pete. That was very clearly explained and shown.

+1

[Pete44ru]

Thgankks for the kind words - IMHO, it's about a half six-pack job.

.

[KCSO]

Hey thats MY bench! I was going to refer him to this, thanks.

[hightime]

I'm reading too. Thanks.

Owen