I am looking for any info on cutting rotary dovetails. They were found on the Remington 12 series and were cut into the barrels to hold the mag tubes. Any schematics or chicken scratches you may have. Thanks again,

Adam

They are cut with a single tool.
The dovetail cutter is centered on the bbl and is plunge cut straight down into the bbl to the depth of the dovetail.
That straight down cut forms a straight sided cut in the bbl as if an end mill was used.

Then the cutter is moved side to side (towards the breech & towards the muzzle) just enought to then cut the dovetail portion of the cut.

The cutter is then moved back to it's original center and withdrawn from the work. That leaves the rotary dovetail cut in the bbl.
The mag tube ring is made with a matching dovetail and size and mearly twists 90 degrees into the cut.
Fit is by interference fit,,not by any taper machined into the dovetail engagement surfaces of either part.

You might inquire at Winchester forums. Some of the older model Win lever guns (1873) had a dovetail that retained a magazine tube retaining ring.

There are several differnent diameters of the rotarty dovetails. Winchester used at least two, Reminton had another.

What I have done is grind a matching 60 degree tool, to go into my boring head. Slot the barrel in the proper postion and depth and min width with say a 1/4" endmill. Then using the above form tool and the boring head, center it in where you want the dovetail, drop the cutter to the bottom of the slot and slowly open the diameter of the boring head about .005" and hand rotate the spindle, cutting the inside taper fo the rotarty dovetail. Adjust and repeat.

Yes it is slow work, but you can work the cutter out in small steps to about .003" under your new ring, and final fit the ring to the dovetail.

What Winchester did was use a profiler, to cut each side of the dovetail with a smaller cutter.

As always there is more than one way to skin a rabbit.

J Wisner