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Extractor Cut in Barrel Shank?

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  • Extractor Cut in Barrel Shank?

    This is a little hard to describe in words, so bear with me. I have a Little Machine Shop Model 3990 Mini-mill. I have a barrel for a Model 03 A3 Springfield that is threaded, but short chambered and needs the groove for the extractor cut. The ideal situation would be to mount the barrel vertically breech end up in the mill vise and simply cut the groove by moving the table side to side, deepening with each pass per usual procedure. Unfortunately this would involve having a large hole in the mill table and vise to accomodate the rest of the barrel from chamber to muzzle. My mill has no such feature. The only way I see to cut the groove using my mill is to mount the barrel horizontally in the vise and make a series of horizontal cuts until the extractor groove is roughed out. This would be followed by filing to final dimensions. Anybody have any other ideas how to accomplish this?

  • #2
    Would a keyseat cutter work, I'm not a gunsmith and cannot picture
    exactly what the setup looks like.
    Larry

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    • #3
      Sounds like the perfect job for a slitting saw.

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      • #4
        Some of the mini mills have a column that tilts to one side. You might be able to move the mill to the end of the bench, and mount the barrel on a fixture that hold it at 45 degrees with the muzzle hanging over the edge of the table. Then tilt the column to match. That would allow you to lock the X,Y and Z axis and use the spindle fine feed to cut the extractor groove with a small end mill.

        Dan
        At the end of the project, there is a profound difference between spare parts and left over parts.

        Location: SF East Bay.

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        • #5
          Woodruf key cutter will do fine. Torque the barrel up, then mark your cut to match the raceway. Then cut.

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          • #6
            Thanks for the replies! I was thinking about a T-slot cutter, but that won't do deep enough cuts. Looks like a woodruff/keyway cutter is the answer.
            Last edited by Fritz1255; 04-18-2020, 08:06 PM.

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            • #7
              Originally posted by Fritz1255 View Post
              Thanks for the replies! Looks like a T-slot cutter would be the ideal tool. Anybody have experience with using these for jobs other than cutting T-slots?
              They are "Woodruff Key Cutters" (as already pointed out) and they are used for all sorts of things other than
              cutting tee-slots...

              Keith
              __________________________
              Just one project too many--that's what finally got him...

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              • #8
                Why not a reinforced cut off type disc in a dremel type tool or die grinder? The cut does not need to be pretty since it is not really visible and I think it could be done in less time than it takes to set your machine up to do the cut. Honestly, a file would do the job well and be quick as well.

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                • #9
                  I had a similar issue on making an extractor cut on my rebarreled #3 Ruger. I mounted the barrel horizontally in the mill, and used a 1/8" wide key cutter. Although most would like an aesthetically pleasing cut, as long as the extractor can get in there, and do it's job, the looks are not really that important. Measuring, and getting the cut to align perfectly with the extractor, on the final barrel torque up, was my biggest worry.

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                  • #10
                    > Model 03 A3 Springfield

                    It's probably too late to help, but search "US Rifles & Machine Guns Colvin Viall" and you'll get hits on paper books or downloadable .PDFs of the instruction manual and blueprint set the Arsenal put sent out to subcontractors building the Springfield. They had Colvin write it, and he also published it in pieces in "American Machinist."

                    It has pictures and details of each forging, each fixture, each setup, each cutter, speeds, feeds, and coolants, and heat treats. All hand-operated machinery, most without power feeds. The most sophisticated machines were the ones making the stocks; I'm pretty sure an '03 stock was the most expensive part of the whole rifle.

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                    • #11
                      Can you do it in the lathe? end mill in the chuck/ collet and set up the barrel on top of the compound at the desired angle. It's a very light cut so a super rigid set-up should not needed.
                      I used to do a lot of light milling on my lathe, back in the days before other machines.

                      Joe B

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                      • #12
                        Strange how perfectly good posts ( and a potentially informative discussion) disappear into the either. OP fellow "Fritz" posts a question, looking for advise ... gets several answers/ suggestions and then disappears. No response, thank you or "go jump" ... funny? Did he get his problem solved? or did the virus get him?

                        Joe B

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                        • #13
                          Original 03A3 barrels came with the extractor cut made, front sight base installed, and a witness mark on the left side of the barrel adjacent to the receiver. The receivers had a witness mark as well. The barrels were short chambered, and the smith had two jobs, cut the barrel shoulder to bring the witness marks into time, then chamber to fit. The bolt to barrel clearance "usually" had adequate clearance, but should be checked. Unlike a Model 70 Winchester, the 03A3 extractor cut is flat, so a woodruff cutter works well.

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